Target Mode Ohai

Signed-off-by: Lamont Granquist <lamont@scriptkiddie.org>

63 files changed, 704 insertions, 483 deletions

diff --git a/.expeditor/run_linux_tests.sh b/.expeditor/run_linux_tests.sh
index 7df19364..ee1a9627 100755
--- a/.expeditor/run_linux_tests.sh
+++ b/.expeditor/run_linux_tests.sh
@@ -9,6 +9,9 @@ export LANG=C.UTF-8 LANGUAGE=C.UTF-8
 
 echo "--- bundle install"
 
+# we need the ruby 2.7 version of bundler, the 2.5/2.6 versions cannot pull our Gemfile correctly
+gem update --system
+gem install bundler
 bundle config --local path vendor/bundle
 bundle install --jobs=7 --retry=3
 
diff --git a/.expeditor/verify.pipeline.yml b/.expeditor/verify.pipeline.yml
index 91660d55..87e55fba 100644
--- a/.expeditor/verify.pipeline.yml
+++ b/.expeditor/verify.pipeline.yml
@@ -26,14 +26,6 @@ steps:
       docker:
         image: ruby:2.7-buster
 
-- label: run-specs-ruby-2.5
-  command:
-    - .expeditor/run_linux_tests.sh rspec
-  expeditor:
-    executor:
-      docker:
-        image: ruby:2.5-buster
-
 - label: run-specs-ruby-2.6
   command:
     - .expeditor/run_linux_tests.sh rspec
@@ -52,6 +44,9 @@ steps:
 
 - label: run-specs-windows
   command:
+    # we need the ruby 2.7 version of bundler, the 2.5/2.6 versions cannot pull our Gemfile correctly
+    - gem update --system
+    - gem install bundler
     - bundle config --local path vendor/bundle
     - bundle install --jobs=7 --retry=3 --without=profile
     - bundle exec rake spec
diff --git a/Gemfile b/Gemfile
index 229e58b0..84cb998b 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,6 +2,10 @@ source "https://rubygems.org"
 
 gemspec
 
+# pull these gems from master of chef/chef so that we're testing against what we will release
+gem "chef-config", git: "https://github.com/chef/chef", glob: "chef-config/chef-config.gemspec"
+gem "chef-utils", git: "https://github.com/chef/chef", glob: "chef-utils/chef-utils.gemspec"
+
 # NOTE: do not submit PRs to add pry as a dep, add to your Gemfile.local
 group :development do
   gem "chefstyle", git: "https://github.com/chef/chefstyle.git", branch: "master"
diff --git a/lib/ohai/application.rb b/lib/ohai/application.rb
index 49b7d5e9..64472245 100644
--- a/lib/ohai/application.rb
+++ b/lib/ohai/application.rb
@@ -56,6 +56,15 @@ class Ohai::Application
     description: "Set the log file location, defaults to STDOUT - recommended for daemonizing",
     proc: nil
 
+  option :target,
+    short: "-t TARGET",
+    long: "--target TARGET",
+    description: "Target Ohai against a remote system or device",
+    proc: lambda { |target|
+      Ohai::Log.warn "-- EXPERIMENTAL -- Target mode activated -- EXPERIMENTAL --"
+      target
+    }
+
   option :help,
     short: "-h",
     long: "--help",
@@ -93,9 +102,39 @@ class Ohai::Application
 
     load_workstation_config
 
+    merge_configs
+
+    if config[:target]
+      Ohai::Config.target_mode.host = config[:target]
+      if URI.parse(Ohai::Config.target_mode.host).scheme
+        train_config = Train.unpack_target_from_uri(Ohai::Config.target_mode.host)
+        Ohai::Config.target_mode = train_config
+      end
+      Ohai::Config.target_mode.enabled = true
+      Ohai::Config.node_name = Ohai::Config.target_mode.host unless Ohai::Config.node_name
+    end
+
     Ohai::Log.init(Ohai.config[:log_location])
   end
 
+  # @api private
+  def config_file_defaults
+    Ohai::Config.save(true)
+  end
+
+  # @api private
+  def config_file_settings
+    Ohai::Config.save(false)
+  end
+
+  # See lib/chef/knife.rb in the chef/chef github repo
+  #
+  # @api private
+  def merge_configs
+    config.replace(config_file_defaults.merge(default_config).merge(config_file_settings).merge(config))
+    Ohai::Config.merge!(config) # make them both the same
+  end
+
   # Passes config and attributes arguments to Ohai::System then prints the results.
   # Called by the run method after config / logging have been initialized
   #
diff --git a/lib/ohai/dsl/plugin.rb b/lib/ohai/dsl/plugin.rb
index 165ecd39..7e72c41f 100644
--- a/lib/ohai/dsl/plugin.rb
+++ b/lib/ohai/dsl/plugin.rb
@@ -22,6 +22,7 @@ require_relative "../mixin/os"
 require_relative "../mixin/shell_out"
 require_relative "../mixin/seconds_to_human"
 require_relative "../mixin/which"
+require_relative "../mixin/train_helpers"
 require_relative "../hints"
 
 module Ohai
@@ -86,10 +87,12 @@ module Ohai
       include Ohai::Mixin::ShellOut
       include Ohai::Mixin::SecondsToHuman
       include Ohai::Mixin::Which
+      include Ohai::Mixin::TrainHelpers
 
       attr_reader :data
       attr_reader :failed
       attr_reader :logger
+      attr_accessor :transport_connection
 
       def initialize(data, logger)
         @data = data
@@ -98,6 +101,10 @@ module Ohai
         @failed = false
       end
 
+      def target_mode?
+        !!@transport_connection
+      end
+
       def run
         @has_run = true
 
diff --git a/lib/ohai/dsl/plugin/versionvii.rb b/lib/ohai/dsl/plugin/versionvii.rb
index 2c54c688..7e41be24 100644
--- a/lib/ohai/dsl/plugin/versionvii.rb
+++ b/lib/ohai/dsl/plugin/versionvii.rb
@@ -46,7 +46,8 @@ module Ohai
           :version7
         end
 
-        # the source of the plugin on disk. This is an array since a plugin may exist for multiple platforms and this would include each of those platform specific file paths
+        # The source of the plugin on disk. This is an array since a plugin may exist for multiple
+        # oses and this would include each of those os specific file paths
         #
         # @return [Array]
         def self.sources
@@ -61,7 +62,7 @@ module Ohai
           @depends_attrs ||= []
         end
 
-        # A block per platform for actually performing data collection constructed
+        # A block per os for actually performing data collection constructed
         # by the collect_data method
         #
         # @return [Mash]
@@ -101,15 +102,16 @@ module Ohai
           !!@optional
         end
 
-        # define data collection methodology per platform
+        # define data collection methodology per os
         #
-        # @param platform [Symbol] the platform to collect data for
-        # @param other_platforms [Array] additional platforms to collect data for
-        # @param block [block] the actual code to collect data for the specified platforms
-        def self.collect_data(platform = :default, *other_platforms, &block)
-          [platform, other_platforms].flatten.each do |plat|
-            Ohai::Log.warn("collect_data already defined on platform '#{plat}' for #{self}, last plugin seen will be used") if data_collector.key?(plat)
-            data_collector[plat] = block
+        # @param os [Array<Symbol>] the list of oses to collect data for
+        # @param block [block] the actual code to collect data for the specified os
+        #
+        def self.collect_data(*os_list, &block)
+          os_list = [ :default ] if os_list.empty?
+          os_list.flatten.each do |os|
+            Ohai::Log.warn("collect_data already defined on os '#{os}' for #{self}, last plugin seen will be used") if data_collector.key?(os)
+            data_collector[os] = block
           end
         end
 
@@ -120,12 +122,22 @@ module Ohai
 
         def run_plugin
           collector = self.class.data_collector
-          platform = collect_os
-
-          if collector.key?(platform)
-            instance_eval(&collector[platform])
-          elsif collector.key?(:default)
+          os = collect_os
+
+          # :default - means any remote or local unix or windows host
+          # :target  - means any remote API which is not unix/windows or otherwise rubyable (cisco switches, IPMI console, HTTP API, etc)
+          #
+          # Do not be confused by the fact that collectors tagged :target do not run against e.g. target-mode ubuntu boxes, that is not
+          # what :target is intended for.  Also, do not be confused by the fact that collectors tagged :default do not run by default against
+          # pure-target mode targets like switches.  That is all intended behavior, the names are problematic.  The :default nomenclature was
+          # invented 10 years before target mode and we are stuck with it.
+          #
+          if collector.key?(os)
+            instance_eval(&collector[os])
+          elsif collector.key?(:default) && !nonruby_target?
             instance_eval(&collector[:default])
+          elsif collector.key?(:target) && nonruby_target?
+            instance_eval(&collector[:target])
           else
             logger.trace("Plugin #{name}: No data to collect. Skipping...")
           end
diff --git a/lib/ohai/mixin/chef_utils_wiring.rb b/lib/ohai/mixin/chef_utils_wiring.rb
index 3ca61c25..468a6977 100644
--- a/lib/ohai/mixin/chef_utils_wiring.rb
+++ b/lib/ohai/mixin/chef_utils_wiring.rb
@@ -16,6 +16,7 @@
 #
 
 require_relative "../config"
+require "singleton" unless defined?(Singleton)
 
 module Ohai
   module Mixin
@@ -32,7 +33,18 @@ module Ohai
       end
 
       def __transport_connection
-        #        Chef.run_context&.transport_connection
+        transport_connection
+      end
+
+      # beause of target mode we cache the PATH to avoid massive amounts of `echo $PATH` remote queries
+      #
+      def __env_path
+        PathCache.instance.path_cache ||= super
+      end
+
+      class PathCache
+        include Singleton
+        attr_accessor :path_cache
       end
     end
   end
diff --git a/lib/ohai/mixin/os.rb b/lib/ohai/mixin/os.rb
index e4e82785..2a2f36ec 100644
--- a/lib/ohai/mixin/os.rb
+++ b/lib/ohai/mixin/os.rb
@@ -27,6 +27,71 @@ module Ohai
       #
       # @return [String] the OS
       def collect_os
+        if target_mode?
+          collect_os_target
+        else
+          collect_os_local
+        end
+      end
+
+      # This should exactly preserve the semantics of collect_os_local below, which is authoritative
+      # for the API and must adhere to pre-existing ohai semantics and not follow inspec's notion of
+      # os/family/hierarchy.
+      #
+      # Right or wrong the ohai `os` variable has matched the ruby `host_os` definition for the past
+      # 10+ years, preceding inspec/train's definitions and this is the documented correct API of
+      # these methods.  Mismatches between the ruby notion and the train version will be fixed as
+      # bugfixes in these methods and may not be considered semver violating even though they make
+      # break downstream consumers.  Please ensure that both methods produce the same results if
+      # you are on a platform which supports running ruby (train is considered authoritative for
+      # any "OS" which cannot run ruby -- server consoles, REST APIs, etc...)
+      #
+      # @api private
+      def collect_os_target
+        case
+        when transport_connection.os.aix?
+          "aix"
+        when transport_connection.os.darwin?
+          "darwin"
+        when transport_connection.os.linux?
+          "linux"
+        when transport_connection.os.family == "freebsd"
+          "freebsd"
+        when transport_connection.os.family == "openbsd"
+          "openbsd"
+        when transport_connection.os.family == "netbsd"
+          "netbsd"
+        when transport_connection.os.family == "dragonflybsd"
+          "dragonflybsd"
+        when transport_connection.os.solaris?
+          "solaris2"
+        when transport_connection.os.windows?
+          "windows"
+
+          #
+          # The purpose of the next two lines is that anything which runs Unix is presumed to be able to run ruby, and
+          # if it was not caught above, we MUST translate whatever train uses as the 'os' into the proper ruby host_os
+          # string.  If it is not unix and not caught above we assume it is something like a REST API which cannot run
+          # ruby.  If these assumptions are incorrect then it is a bug, which should be submitted to fix it, and the
+          # values should not be relied upon until that bug is fixed.  The train os is NEVER considered authoritataive
+          # for any target which can run ruby.
+          #
+        when transport_connection.os.unix?
+          raise "Target mode unsupported on this Unix-like host, please update the collect_os_target case statement with the correct ruby host_os value."
+        else
+          # now we have something like an IPMI console that isn't Unix-like or Windows, presumably cannot run ruby, and
+          # so we just trust the train O/S information.
+          transport_connection.os
+        end
+      end
+
+      # @api private
+      def nonruby_target?
+        transport_connection && !transport_connection.os.unix? && !transport_connection.os.windows
+      end
+
+      # @api private
+      def collect_os_local
         case ::RbConfig::CONFIG["host_os"]
         when /aix(.+)$/
           "aix"
@@ -56,7 +121,7 @@ module Ohai
         end
       end
 
-      module_function :collect_os
+      extend self
     end
   end
 end
diff --git a/lib/ohai/mixin/train_helpers.rb b/lib/ohai/mixin/train_helpers.rb
new file mode 100644
index 00000000..92951388
--- /dev/null
+++ b/lib/ohai/mixin/train_helpers.rb
@@ -0,0 +1,35 @@
+#
+# Copyright:: Copyright (c) Chef Software Inc.
+# License:: Apache License, Version 2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+require "chef-utils/dsl/train_helpers" unless defined?(ChefUtils::DSL::TrainHelpers)
+require_relative "chef_utils_wiring" unless defined?(Ohai::Mixin::ChefUtilsWiring)
+
+module Ohai
+  module Mixin
+    module TrainHelpers
+      include ChefUtils::DSL::TrainHelpers
+      include ChefUtilsWiring
+
+      # anything added to this file temporarily should be pushed back up
+      # into ChefUtils::DSL::TrainHelpers
+
+      # XXX: this needs better support directly in train
+      def dir_glob(path)
+        shell_out!("ls -d #{path}").stdout.split
+      end
+    end
+  end
+end
diff --git a/lib/ohai/plugins/azure.rb b/lib/ohai/plugins/azure.rb
index 31cbaeed..99eae86c 100644
--- a/lib/ohai/plugins/azure.rb
+++ b/lib/ohai/plugins/azure.rb
@@ -47,7 +47,7 @@ Ohai.plugin(:Azure) do
   # check for either the waagent or the unknown-245 DHCP option that Azure uses
   # http://blog.mszcool.com/index.php/2015/04/detecting-if-a-virtual-machine-runs-in-microsoft-azure-linux-windows-to-protect-your-software-when-distributed-via-the-azure-marketplace/
   def has_waagent?
-    if File.exist?("/usr/sbin/waagent") || Dir.exist?('C:\WindowsAzure')
+    if file_exist?("/usr/sbin/waagent") || dir_exist?('C:\WindowsAzure')
       logger.trace("Plugin Azure: Found waagent used by Azure.")
       true
     end
@@ -55,8 +55,8 @@ Ohai.plugin(:Azure) do
 
   def has_dhcp_option_245?
     has_245 = false
-    if File.exist?("/var/lib/dhcp/dhclient.eth0.leases")
-      File.open("/var/lib/dhcp/dhclient.eth0.leases").each do |line|
+    if file_exist?("/var/lib/dhcp/dhclient.eth0.leases")
+      file_open("/var/lib/dhcp/dhclient.eth0.leases").each do |line|
         if /unknown-245/.match?(line)
           logger.trace("Plugin Azure: Found unknown-245 DHCP option used by Azure.")
           has_245 = true
diff --git a/lib/ohai/plugins/bsd/virtualization.rb b/lib/ohai/plugins/bsd/virtualization.rb
index f1f03ea2..445d1e75 100644
--- a/lib/ohai/plugins/bsd/virtualization.rb
+++ b/lib/ohai/plugins/bsd/virtualization.rb
@@ -66,7 +66,7 @@ Ohai.plugin(:Virtualization) do
     end
 
     # Detect bhyve by presence of /dev/vmm
-    if File.exist?("/dev/vmm")
+    if file_exist?("/dev/vmm")
       virtualization[:system] = "bhyve"
       virtualization[:role] = "host"
       virtualization[:systems][:bhyve] = "host"
diff --git a/lib/ohai/plugins/chef.rb b/lib/ohai/plugins/chef.rb
index e89a9a1f..fc588ea3 100644
--- a/lib/ohai/plugins/chef.rb
+++ b/lib/ohai/plugins/chef.rb
@@ -19,7 +19,7 @@
 Ohai.plugin(:Chef) do
   provides "chef_packages/chef"
 
-  collect_data do
+  collect_data(:default, :target) do
     begin
       require "chef/version"
     rescue Gem::LoadError
diff --git a/lib/ohai/plugins/cpu.rb b/lib/ohai/plugins/cpu.rb
index d223405d..fd410dd2 100644
--- a/lib/ohai/plugins/cpu.rb
+++ b/lib/ohai/plugins/cpu.rb
@@ -30,7 +30,7 @@ Ohai.plugin(:CPU) do
   def parse_bsd_dmesg(&block)
     cpuinfo = Mash.new
     cpuinfo["flags"] = []
-    File.open("/var/run/dmesg.boot").each do |line|
+    file_open("/var/run/dmesg.boot").each do |line|
       case line
       when /CPU:\s+(.+) \(([\d.]+).+\)/
         cpuinfo["model_name"] = $1
@@ -53,7 +53,7 @@ Ohai.plugin(:CPU) do
     cpu_number = 0
     current_cpu = nil
 
-    File.open("/proc/cpuinfo").each do |line|
+    file_open("/proc/cpuinfo").each do |line|
       case line
       when /processor\s+:\s(.+)/
         cpuinfo[$1] = Mash.new
@@ -212,7 +212,7 @@ Ohai.plugin(:CPU) do
     # to scrape from dmesg.boot is the cpu feature list.
     # cpu0: FPU,V86,DE,PSE,TSC,MSR,MCE,CX8,SEP,MTRR,PGE,MCA,CMOV,PAT,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,TM,SBF,EST,TM2
 
-    File.open("/var/run/dmesg.boot").each do |line|
+    file_open("/var/run/dmesg.boot").each do |line|
       case line
       when /cpu\d+:\s+([A-Z]+$|[A-Z]+,.*$)/
         cpuinfo["flags"] = $1.downcase.split(",")
@@ -235,7 +235,7 @@ Ohai.plugin(:CPU) do
     # available instruction set
     # cpu0 at mainbus0 apid 0: Intel 686-class, 2134MHz, id 0x6f6
 
-    File.open("/var/run/dmesg.boot").each do |line|
+    file_open("/var/run/dmesg.boot").each do |line|
       case line
       when /cpu[\d\w\s]+:\s([\w\s\-]+),\s+(\w+),/
         cpuinfo[:model_name] = $1
diff --git a/lib/ohai/plugins/darwin/virtualization.rb b/lib/ohai/plugins/darwin/virtualization.rb
index 59732118..c14d0857 100644
--- a/lib/ohai/plugins/darwin/virtualization.rb
+++ b/lib/ohai/plugins/darwin/virtualization.rb
@@ -35,7 +35,7 @@ Ohai.plugin(:Virtualization) do
   end
 
   def fusion_exists?
-    ::File.exist?("/Applications/VMware\ Fusion.app/")
+    file_exist?("/Applications/VMware\ Fusion.app/")
   end
 
   def docker_exists?
diff --git a/lib/ohai/plugins/ec2.rb b/lib/ohai/plugins/ec2.rb
index 8d4fdb63..073ff780 100644
--- a/lib/ohai/plugins/ec2.rb
+++ b/lib/ohai/plugins/ec2.rb
@@ -97,8 +97,8 @@ Ohai.plugin(:EC2) do
   # @param path[String] abs path to the file
   # @return [String] contents of the file if it exists
   def file_val_if_exists(path)
-    if ::File.exist?(path)
-      ::File.read(path)
+    if file_exist?(path)
+      file_read(path)
     end
   end
 
diff --git a/lib/ohai/plugins/filesystem.rb b/lib/ohai/plugins/filesystem.rb
index 00aaaf62..4d8c7ce1 100644
--- a/lib/ohai/plugins/filesystem.rb
+++ b/lib/ohai/plugins/filesystem.rb
@@ -29,7 +29,7 @@ Ohai.plugin(:Filesystem) do
   def find_device(name)
     %w{/dev /dev/mapper}.each do |dir|
       path = File.join(dir, name)
-      return path if File.exist?(path)
+      return path if file_exist?(path)
     end
     name
   end
@@ -371,11 +371,11 @@ Ohai.plugin(:Filesystem) do
     end
 
     # Grab any missing mount information from /proc/mounts
-    if File.exist?("/proc/mounts")
+    if file_exist?("/proc/mounts")
       mounts = ""
       # Due to https://tickets.opscode.com/browse/OHAI-196
       # we have to non-block read dev files. Ew.
-      f = File.open("/proc/mounts")
+      f = file_open("/proc/mounts")
       loop do
         data = f.read_nonblock(4096)
         mounts << data
diff --git a/lib/ohai/plugins/gce.rb b/lib/ohai/plugins/gce.rb
index db336dfe..cd0bd63c 100644
--- a/lib/ohai/plugins/gce.rb
+++ b/lib/ohai/plugins/gce.rb
@@ -40,8 +40,8 @@ Ohai.plugin(:GCE) do
   # @param path[String] abs path to the file
   # @return [String] contents of the file if it exists
   def file_val_if_exists(path)
-    if ::File.exist?(path)
-      ::File.read(path)
+    if file_exist?(path)
+      file_read(path)
     end
   end
 
diff --git a/lib/ohai/plugins/init_package.rb b/lib/ohai/plugins/init_package.rb
index 6d83275a..20a8f512 100644
--- a/lib/ohai/plugins/init_package.rb
+++ b/lib/ohai/plugins/init_package.rb
@@ -20,6 +20,6 @@ Ohai.plugin(:InitPackage) do
   provides "init_package"
 
   collect_data(:linux) do
-    init_package File.exist?("/proc/1/comm") ? File.open("/proc/1/comm").gets.chomp : "init"
+    init_package file_exist?("/proc/1/comm") ? file_open("/proc/1/comm").gets.chomp : "init"
   end
 end
diff --git a/lib/ohai/plugins/joyent.rb b/lib/ohai/plugins/joyent.rb
index 118ea907..8df1774c 100644
--- a/lib/ohai/plugins/joyent.rb
+++ b/lib/ohai/plugins/joyent.rb
@@ -25,7 +25,7 @@ Ohai.plugin(:Joyent) do
   depends "os", "platform", "virtualization"
 
   def collect_product_file
-    data = ::File.read("/etc/product") rescue nil
+    data = file_read("/etc/product") rescue nil
     if data
       data.strip.split("\n")
     else
@@ -34,7 +34,7 @@ Ohai.plugin(:Joyent) do
   end
 
   def collect_pkgsrc
-    data = ::File.read("/opt/local/etc/pkg_install.conf") rescue nil
+    data = file_read("/opt/local/etc/pkg_install.conf") rescue nil
     if data
       /PKG_PATH=(.*)/.match(data)[1] rescue nil
     end
diff --git a/lib/ohai/plugins/kernel.rb b/lib/ohai/plugins/kernel.rb
index 6fdfc1fd..19936364 100644
--- a/lib/ohai/plugins/kernel.rb
+++ b/lib/ohai/plugins/kernel.rb
@@ -156,6 +156,10 @@ Ohai.plugin(:Kernel) do
     ].include?(name)
   end
 
+  collect_data(:target) do
+    # intentionally left blank
+  end
+
   collect_data(:default) do
     kernel init_kernel
   end
@@ -204,8 +208,8 @@ Ohai.plugin(:Kernel) do
       if line =~ /([a-zA-Z0-9\_]+)\s+(\d+)\s+(\d+)/
         modules[$1] = { size: $2, refcount: $3 }
         # Making sure to get the module version that has been loaded
-        if File.exist?("/sys/module/#{$1}/version")
-          version = File.read("/sys/module/#{$1}/version").chomp.strip
+        if file_exist?("/sys/module/#{$1}/version")
+          version = file_read("/sys/module/#{$1}/version").chomp.strip
           modules[$1]["version"] = version unless version.empty?
         end
       end
@@ -230,7 +234,7 @@ Ohai.plugin(:Kernel) do
     so = shell_out("uname -s")
     kernel[:os] = so.stdout.split($/)[0]
 
-    so = File.open("/etc/release", &:gets)
+    so = file_open("/etc/release", &:gets)
     md = /(?<update>\d.*\d)/.match(so)
     kernel[:update] = md[:update] if md
 
diff --git a/lib/ohai/plugins/linux/block_device.rb b/lib/ohai/plugins/linux/block_device.rb
index c211ebac..419021ad 100644
--- a/lib/ohai/plugins/linux/block_device.rb
+++ b/lib/ohai/plugins/linux/block_device.rb
@@ -20,24 +20,24 @@ Ohai.plugin(:BlockDevice) do
   provides "block_device"
 
   collect_data(:linux) do
-    if File.exist?("/sys/block")
+    if file_exist?("/sys/block")
       block = Mash.new
-      Dir["/sys/block/*"].each do |block_device_dir|
+      dir_glob("/sys/block/*").each do |block_device_dir|
         dir = File.basename(block_device_dir)
         block[dir] = Mash.new
         %w{size removable}.each do |check|
-          if File.exist?("/sys/block/#{dir}/#{check}")
-            File.open("/sys/block/#{dir}/#{check}") { |f| block[dir][check] = f.read_nonblock(1024).strip }
+          if file_exist?("/sys/block/#{dir}/#{check}")
+            file_open("/sys/block/#{dir}/#{check}") { |f| block[dir][check] = f.read_nonblock(1024).strip }
           end
         end
         %w{model rev state timeout vendor queue_depth}.each do |check|
-          if File.exist?("/sys/block/#{dir}/device/#{check}")
-            File.open("/sys/block/#{dir}/device/#{check}") { |f| block[dir][check] = f.read_nonblock(1024).strip }
+          if file_exist?("/sys/block/#{dir}/device/#{check}")
+            file_open("/sys/block/#{dir}/device/#{check}") { |f| block[dir][check] = f.read_nonblock(1024).strip }
           end
         end
         %w{rotational physical_block_size logical_block_size}.each do |check|
-          if File.exist?("/sys/block/#{dir}/queue/#{check}")
-            File.open("/sys/block/#{dir}/queue/#{check}") { |f| block[dir][check] = f.read_nonblock(1024).strip }
+          if file_exist?("/sys/block/#{dir}/queue/#{check}")
+            file_open("/sys/block/#{dir}/queue/#{check}") { |f| block[dir][check] = f.read_nonblock(1024).strip }
           end
         end
       end
diff --git a/lib/ohai/plugins/linux/interrupts.rb b/lib/ohai/plugins/linux/interrupts.rb
index 74769019..cd5f4272 100644
--- a/lib/ohai/plugins/linux/interrupts.rb
+++ b/lib/ohai/plugins/linux/interrupts.rb
@@ -25,7 +25,7 @@ Ohai.plugin(:Interrupts) do
   # format: comma-separate list of 32bit bitmask in hex
   # each bit is a CPU, right to left ordering (i.e. CPU0 is rightmost)
   def parse_smp_affinity(path, cpus)
-    masks = File.read(path).strip
+    masks = file_read(path).strip
     bit_masks = []
     masks.split(",").each do |mask|
       bit_masks << mask.rjust(8, "0").to_i(16).to_s(2)
@@ -47,7 +47,7 @@ Ohai.plugin(:Interrupts) do
       parse_smp_affinity("/proc/irq/default_smp_affinity", cpus)
 
     interrupts[:irq] = Mash.new
-    File.open("/proc/interrupts").each do |line|
+    file_open("/proc/interrupts").each do |line|
       # Documentation: https://www.kernel.org/doc/Documentation/filesystems/proc.txt
       # format is "{irqn}: {CPUn...} [type] [vector] [device]"
       irqn, fields = line.split(":", 2)
@@ -70,7 +70,7 @@ Ohai.plugin(:Interrupts) do
         interrupts[:irq][irqn][:vector],
         interrupts[:irq][irqn][:device] =
           fields[cpus].split
-        if File.exist?("/proc/irq/#{irqn}/smp_affinity")
+        if file_exist?("/proc/irq/#{irqn}/smp_affinity")
           interrupts[:irq][irqn][:smp_affinity_by_cpu] =
             parse_smp_affinity("/proc/irq/#{irqn}/smp_affinity", cpus)
         end
diff --git a/lib/ohai/plugins/linux/lsb.rb b/lib/ohai/plugins/linux/lsb.rb
index f96de959..382d1534 100644
--- a/lib/ohai/plugins/linux/lsb.rb
+++ b/lib/ohai/plugins/linux/lsb.rb
@@ -22,7 +22,7 @@ Ohai.plugin(:LSB) do
   collect_data(:linux) do
     lsb Mash.new
 
-    if File.exist?("/usr/bin/lsb_release")
+    if file_exist?("/usr/bin/lsb_release")
       # From package redhat-lsb on Fedora/Redhat, lsb-release on Debian/Ubuntu
       shell_out("lsb_release -a").stdout.lines do |line|
         case line
@@ -38,9 +38,9 @@ Ohai.plugin(:LSB) do
           lsb[:id] = line
         end
       end
-    elsif File.exist?("/etc/lsb-release")
+    elsif file_exist?("/etc/lsb-release")
       # Old, non-standard Debian support
-      File.open("/etc/lsb-release").each do |line|
+      file_open("/etc/lsb-release").each do |line|
         case line
         when /^DISTRIB_ID=["']?(.+?)["']?$/
           lsb[:id] = $1
diff --git a/lib/ohai/plugins/linux/machineid.rb b/lib/ohai/plugins/linux/machineid.rb
index 565bfde1..c87a15f0 100644
--- a/lib/ohai/plugins/linux/machineid.rb
+++ b/lib/ohai/plugins/linux/machineid.rb
@@ -20,10 +20,10 @@ Ohai.plugin(:Machineid) do
   provides "machine_id"
 
   collect_data(:linux) do
-    if ::File.exist?("/etc/machine-id")
-      mid = ::File.read("/etc/machine-id").chomp
-    elsif ::File.exist?("/var/lib/dbus/machine-id")
-      mid = ::File.read("/var/lib/dbus/machine-id").chomp
+    if file_exist?("/etc/machine-id")
+      mid = file_read("/etc/machine-id").chomp
+    elsif file_exist?("/var/lib/dbus/machine-id")
+      mid = file_read("/var/lib/dbus/machine-id").chomp
     else
       mid = nil
     end
diff --git a/lib/ohai/plugins/linux/mdadm.rb b/lib/ohai/plugins/linux/mdadm.rb
index 925817dc..b33b4b0d 100644
--- a/lib/ohai/plugins/linux/mdadm.rb
+++ b/lib/ohai/plugins/linux/mdadm.rb
@@ -53,9 +53,9 @@ Ohai.plugin(:Mdadm) do
 
   collect_data(:linux) do
     # gather a list of all raid arrays
-    if File.exist?("/proc/mdstat")
+    if file_exist?("/proc/mdstat")
       devices = {}
-      File.open("/proc/mdstat").each do |line|
+      file_open("/proc/mdstat").each do |line|
         if line =~ /(md[0-9]+)/
           device = Regexp.last_match[1]
           pieces = line.split(/\s+/)
diff --git a/lib/ohai/plugins/linux/memory.rb b/lib/ohai/plugins/linux/memory.rb
index 048516be..328cb49f 100644
--- a/lib/ohai/plugins/linux/memory.rb
+++ b/lib/ohai/plugins/linux/memory.rb
@@ -25,7 +25,7 @@ Ohai.plugin(:Memory) do
     memory[:hugepages] = Mash.new
     memory[:directmap] = Mash.new
 
-    File.open("/proc/meminfo").each do |line|
+    file_open("/proc/meminfo").each do |line|
       case line
       when /^MemTotal:\s+(\d+) (.+)$/
         memory[:total] = "#{$1}#{$2}"
diff --git a/lib/ohai/plugins/linux/network.rb b/lib/ohai/plugins/linux/network.rb
index 80796d0c..03fbffa4 100644
--- a/lib/ohai/plugins/linux/network.rb
+++ b/lib/ohai/plugins/linux/network.rb
@@ -35,7 +35,7 @@ Ohai.plugin(:Network) do
   end
 
   def ipv6_enabled?
-    File.exist? "/proc/net/if_inet6"
+    file_exist? "/proc/net/if_inet6"
   end
 
   def ethtool_binary_path
@@ -43,11 +43,11 @@ Ohai.plugin(:Network) do
   end
 
   def is_openvz?
-    @openvz ||= ::File.directory?("/proc/vz")
+    @openvz ||= file_directory?("/proc/vz")
   end
 
   def is_openvz_host?
-    is_openvz? && ::File.directory?("/proc/bc")
+    is_openvz? && file_directory?("/proc/bc")
   end
 
   def extract_neighbors(family, iface, neigh_attr)
diff --git a/lib/ohai/plugins/linux/platform.rb b/lib/ohai/plugins/linux/platform.rb
index de3b53ec..31c4d75c 100644
--- a/lib/ohai/plugins/linux/platform.rb
+++ b/lib/ohai/plugins/linux/platform.rb
@@ -43,9 +43,9 @@ Ohai.plugin(:Platform) do
   # @returns [Hash] the file parsed into a Hash or nil
   #
   def read_os_release_info(file)
-    return nil unless File.exist?(file)
+    return nil unless file_exist?(file)
 
-    File.read(file).split.inject({}) do |map, line|
+    file_read(file).split.inject({}) do |map, line|
       key, value = line.split("=")
       map[key] = value.gsub(/\A"|"\Z/, "") if value
       map
@@ -64,7 +64,7 @@ Ohai.plugin(:Platform) do
       begin
         os_release_info = read_os_release_info("/etc/os-release")
         cisco_release_info = os_release_info["CISCO_RELEASE_INFO"] if os_release_info
-        if cisco_release_info && File.exist?(cisco_release_info)
+        if cisco_release_info && file_exist?(cisco_release_info)
           os_release_info.merge!(read_os_release_info(cisco_release_info))
         end
         os_release_info
@@ -77,7 +77,7 @@ Ohai.plugin(:Platform) do
   # @returns [Boolean] if we are Cisco according to /etc/os-release
   #
   def os_release_file_is_cisco?
-    File.exist?("/etc/os-release") && os_release_info["CISCO_RELEASE_INFO"]
+    file_exist?("/etc/os-release") && os_release_info["CISCO_RELEASE_INFO"]
   end
 
   #
@@ -88,7 +88,7 @@ Ohai.plugin(:Platform) do
   # @returns [String] bigip Linux version from /etc/f5-release
   #
   def bigip_version
-    release_contents = File.read("/etc/f5-release")
+    release_contents = file_read("/etc/f5-release")
     release_contents.match(/BIG-IP release (\S*)/)[1] # http://rubular.com/r/O8nlrBVqSb
   rescue NoMethodError, Errno::ENOENT, Errno::EACCES # rescue regex failure, file missing, or permission denied
     logger.warn("Detected F5 Big-IP, but /etc/f5-release could not be parsed to determine platform_version")
@@ -178,18 +178,18 @@ Ohai.plugin(:Platform) do
   # @deprecated
   def legacy_platform_detection
     # platform [ and platform_version ? ] should be lower case to avoid dealing with RedHat/Redhat/redhat matching
-    if File.exist?("/etc/oracle-release")
-      contents = File.read("/etc/oracle-release").chomp
+    if file_exist?("/etc/oracle-release")
+      contents = file_read("/etc/oracle-release").chomp
       platform "oracle"
       platform_version get_redhatish_version(contents)
-    elsif File.exist?("/etc/enterprise-release")
-      contents = File.read("/etc/enterprise-release").chomp
+    elsif file_exist?("/etc/enterprise-release")
+      contents = file_read("/etc/enterprise-release").chomp
       platform "oracle"
       platform_version get_redhatish_version(contents)
-    elsif File.exist?("/etc/f5-release")
+    elsif file_exist?("/etc/f5-release")
       platform "bigip"
       platform_version bigip_version
-    elsif File.exist?("/etc/debian_version")
+    elsif file_exist?("/etc/debian_version")
       # Ubuntu and Debian both have /etc/debian_version
       # Ubuntu should always have a working lsb, debian does not by default
       if /Ubuntu/i.match?(lsb[:id])
@@ -197,25 +197,25 @@ Ohai.plugin(:Platform) do
         platform_version lsb[:release]
       else
         platform "debian"
-        platform_version File.read("/etc/debian_version").chomp
+        platform_version file_read("/etc/debian_version").chomp
       end
-    elsif File.exist?("/etc/parallels-release")
-      contents = File.read("/etc/parallels-release").chomp
+    elsif file_exist?("/etc/parallels-release")
+      contents = file_read("/etc/parallels-release").chomp
       platform get_redhatish_platform(contents)
       platform_version contents.match(/(\d\.\d\.\d)/)[0]
-    elsif File.exist?("/etc/Eos-release")
+    elsif file_exist?("/etc/Eos-release")
       platform "arista_eos"
-      platform_version File.read("/etc/Eos-release").strip.split[-1]
-    elsif File.exist?("/etc/redhat-release")
-      contents = File.read("/etc/redhat-release").chomp
+      platform_version file_read("/etc/Eos-release").strip.split[-1]
+    elsif file_exist?("/etc/redhat-release")
+      contents = file_read("/etc/redhat-release").chomp
       platform get_redhatish_platform(contents)
       platform_version get_redhatish_version(contents)
-    elsif File.exist?("/etc/system-release")
-      contents = File.read("/etc/system-release").chomp
+    elsif file_exist?("/etc/system-release")
+      contents = file_read("/etc/system-release").chomp
       platform get_redhatish_platform(contents)
       platform_version get_redhatish_version(contents)
-    elsif File.exist?("/etc/SuSE-release")
-      suse_release = File.read("/etc/SuSE-release")
+    elsif file_exist?("/etc/SuSE-release")
+      suse_release = file_read("/etc/SuSE-release")
       suse_version = suse_release.scan(/VERSION = (\d+)\nPATCHLEVEL = (\d+)/).flatten.join(".")
       suse_version = suse_release[/VERSION = ([\d\.]{2,})/, 1] if suse_version == ""
       platform_version suse_version
@@ -243,16 +243,16 @@ Ohai.plugin(:Platform) do
       end
 
       platform_version os_release_info["VERSION"]
-    elsif File.exist?("/etc/slackware-version")
+    elsif file_exist?("/etc/slackware-version")
       platform "slackware"
-      platform_version File.read("/etc/slackware-version").scan(/(\d+|\.+)/).join
-    elsif File.exist?("/etc/exherbo-release")
+      platform_version file_read("/etc/slackware-version").scan(/(\d+|\.+)/).join
+    elsif file_exist?("/etc/exherbo-release")
       platform "exherbo"
       # no way to determine platform_version in a rolling release distribution
       # kernel release will be used - ex. 3.13
       platform_version shell_out("/bin/uname -r").stdout.strip
-    elsif File.exist?("/usr/lib/os-release")
-      contents = File.read("/usr/lib/os-release")
+    elsif file_exist?("/usr/lib/os-release")
+      contents = file_read("/usr/lib/os-release")
       if /clear-linux-os/.match?(contents) # Clear Linux https://clearlinux.org/
         platform "clearlinux"
         platform_version contents[/VERSION_ID=(\d+)/, 1]
@@ -285,14 +285,14 @@ Ohai.plugin(:Platform) do
   def determine_os_version
     # centos only includes the major version in os-release for some reason
     if os_release_info["ID"] == "centos"
-      get_redhatish_version(File.read("/etc/redhat-release").chomp)
+      get_redhatish_version(file_read("/etc/redhat-release").chomp)
     else
       os_release_info["VERSION_ID"] || shell_out("/bin/uname -r").stdout.strip
     end
   end
 
   collect_data(:linux) do
-    if ::File.exist?("/etc/os-release")
+    if file_exist?("/etc/os-release")
       logger.trace("Plugin platform: Using /etc/os-release for platform detection")
 
       # fixup os-release names to ohai platform names
diff --git a/lib/ohai/plugins/linux/virtualization.rb b/lib/ohai/plugins/linux/virtualization.rb
index 0b48f625..c9e69303 100644
--- a/lib/ohai/plugins/linux/virtualization.rb
+++ b/lib/ohai/plugins/linux/virtualization.rb
@@ -51,15 +51,15 @@ Ohai.plugin(:Virtualization) do
     # - may be able to determine if under paravirt from /dev/xen/evtchn (See OHAI-253)
     # - Additional edge cases likely should not change the above assumptions
     #   but rather be additive - btm
-    if File.exist?("/proc/xen")
+    if file_exist?("/proc/xen")
       virtualization[:system] = "xen"
       # Assume guest
       virtualization[:role] = "guest"
       virtualization[:systems][:xen] = "guest"
 
       # This file should exist on most Xen systems, normally empty for guests
-      if File.exist?("/proc/xen/capabilities")
-        if /control_d/i.match?(File.read("/proc/xen/capabilities"))
+      if file_exist?("/proc/xen/capabilities")
+        if /control_d/i.match?(file_read("/proc/xen/capabilities"))
           logger.trace("Plugin Virtualization: /proc/xen/capabilities contains control_d. Detecting as Xen host")
           virtualization[:role] = "host"
           virtualization[:systems][:xen] = "host"
@@ -68,8 +68,8 @@ Ohai.plugin(:Virtualization) do
     end
 
     # Detect Virtualbox from kernel module
-    if File.exist?("/proc/modules")
-      modules = File.read("/proc/modules")
+    if file_exist?("/proc/modules")
+      modules = file_read("/proc/modules")
       if /^vboxdrv/.match?(modules)
         logger.trace("Plugin Virtualization: /proc/modules contains vboxdrv. Detecting as vbox host")
         virtualization[:system] = "vbox"
@@ -92,8 +92,8 @@ Ohai.plugin(:Virtualization) do
     end
 
     # Detect paravirt KVM/QEMU from cpuinfo, report as KVM
-    if File.exist?("/proc/cpuinfo")
-      if /QEMU Virtual CPU|Common KVM processor|Common 32-bit KVM processor/.match?(File.read("/proc/cpuinfo"))
+    if file_exist?("/proc/cpuinfo")
+      if /QEMU Virtual CPU|Common KVM processor|Common 32-bit KVM processor/.match?(file_read("/proc/cpuinfo"))
         logger.trace("Plugin Virtualization: /proc/cpuinfo lists a KVM paravirt CPU string. Detecting as kvm guest")
         virtualization[:system] = "kvm"
         virtualization[:role] = "guest"
@@ -103,9 +103,9 @@ Ohai.plugin(:Virtualization) do
 
     # Detect KVM systems via /sys
     # guests will have the hypervisor cpu feature that hosts don't have
-    if File.exist?("/sys/devices/virtual/misc/kvm")
+    if file_exist?("/sys/devices/virtual/misc/kvm")
       virtualization[:system] = "kvm"
-      if /hypervisor/.match?(File.read("/proc/cpuinfo"))
+      if /hypervisor/.match?(file_read("/proc/cpuinfo"))
         logger.trace("Plugin Virtualization: /sys/devices/virtual/misc/kvm present and /proc/cpuinfo lists the hypervisor feature. Detecting as kvm guest")
         virtualization[:role] = "guest"
         virtualization[:systems][:kvm] = "guest"
@@ -129,12 +129,12 @@ Ohai.plugin(:Virtualization) do
 
     # Detect OpenVZ / Virtuozzo.
     # http://wiki.openvz.org/BC_proc_entries
-    if File.exist?("/proc/bc/0")
+    if file_exist?("/proc/bc/0")
       logger.trace("Plugin Virtualization: /proc/bc/0 exists. Detecting as openvz host")
       virtualization[:system] = "openvz"
       virtualization[:role] = "host"
       virtualization[:systems][:openvz] = "host"
-    elsif File.exist?("/proc/vz")
+    elsif file_exist?("/proc/vz")
       logger.trace("Plugin Virtualization: /proc/vz exists. Detecting as openvz guest")
       virtualization[:system] = "openvz"
       virtualization[:role] = "guest"
@@ -142,9 +142,9 @@ Ohai.plugin(:Virtualization) do
     end
 
     # Detect Hyper-V guest and the hostname of the host
-    if File.exist?("/var/lib/hyperv/.kvp_pool_3")
+    if file_exist?("/var/lib/hyperv/.kvp_pool_3")
       logger.trace("Plugin Virtualization: /var/lib/hyperv/.kvp_pool_3 contains string indicating Hyper-V guest")
-      data = File.read("/var/lib/hyperv/.kvp_pool_3")
+      data = file_read("/var/lib/hyperv/.kvp_pool_3")
       hyperv_host = data[/\HostName(.*?)HostingSystemEditionId/, 1].scan(/[[:print:]]/).join.downcase
       virtualization[:system] = "hyperv"
       virtualization[:role] = "guest"
@@ -153,8 +153,8 @@ Ohai.plugin(:Virtualization) do
     end
 
     # Detect Linux-VServer
-    if File.exist?("/proc/self/status")
-      proc_self_status = File.read("/proc/self/status")
+    if file_exist?("/proc/self/status")
+      proc_self_status = file_read("/proc/self/status")
       vxid = proc_self_status.match(/^(s_context|VxID):\s*(\d+)$/)
       if vxid && vxid[2]
         virtualization[:system] = "linux-vserver"
@@ -188,8 +188,8 @@ Ohai.plugin(:Virtualization) do
     #
     # Full notes, https://tickets.opscode.com/browse/OHAI-551
     # Kernel docs, https://www.kernel.org/doc/Documentation/cgroups
-    if File.exist?("/proc/self/cgroup")
-      cgroup_content = File.read("/proc/self/cgroup")
+    if file_exist?("/proc/self/cgroup")
+      cgroup_content = file_read("/proc/self/cgroup")
       # These two REs catch many different examples. Here's a specific one
       # from when it is docker and there is no subsystem name.
       # https://rubular.com/r/dV13hiU9KxmiWB
@@ -199,17 +199,17 @@ Ohai.plugin(:Virtualization) do
         virtualization[:system] = $1
         virtualization[:role] = "guest"
         virtualization[:systems][$1.to_sym] = "guest"
-      elsif /container=lxc/.match?(File.read("/proc/1/environ"))
+      elsif /container=lxc/.match?(file_read("/proc/1/environ"))
         logger.trace("Plugin Virtualization: /proc/1/environ indicates lxc container. Detecting as lxc guest")
         virtualization[:system] = "lxc"
         virtualization[:role] = "guest"
         virtualization[:systems][:lxc] = "guest"
-      elsif /container=systemd-nspawn/.match?(File.read("/proc/1/environ"))
+      elsif /container=systemd-nspawn/.match?(file_read("/proc/1/environ"))
         logger.trace("Plugin Virtualization: /proc/1/environ indicates nspawn container. Detecting as nspawn guest")
         virtualization[:system] = "nspawn"
         virtualization[:role] = "guest"
         virtualization[:systems][:nspawn] = "guest"
-      elsif lxc_version_exists? && File.read("/proc/self/cgroup") =~ %r{\d:[^:]+:/$}
+      elsif lxc_version_exists? && file_read("/proc/self/cgroup") =~ %r{\d:[^:]+:/$}
         # lxc-version shouldn't be installed by default
         # Even so, it is likely we are on an LXC capable host that is not being used as such
         # So we're cautious here to not overwrite other existing values (OHAI-573)
@@ -224,7 +224,7 @@ Ohai.plugin(:Virtualization) do
         # If so, we may need to look further for a differentiator (OHAI-573)
         virtualization[:systems][:lxc] = "host"
       end
-    elsif File.exist?("/.dockerenv") || File.exist?("/.dockerinit")
+    elsif file_exist?("/.dockerenv") || file_exist?("/.dockerinit")
       logger.trace("Plugin Virtualization: .dockerenv or .dockerinit exist. Detecting as docker guest")
       virtualization[:system] = "docker"
       virtualization[:role] = "guest"
@@ -233,7 +233,7 @@ Ohai.plugin(:Virtualization) do
 
     # Detect LXD
     # See https://github.com/lxc/lxd/blob/master/doc/dev-lxd.md
-    if File.exist?("/dev/lxd/sock")
+    if file_exist?("/dev/lxd/sock")
       logger.trace("Plugin Virtualization: /dev/lxd/sock exists. Detecting as lxd guest")
       virtualization[:system] = "lxd"
       virtualization[:role] = "guest"
@@ -248,7 +248,7 @@ Ohai.plugin(:Virtualization) do
       # Snap based installations utilize '/var/snap/lxd/common/lxd/'
       #   - includes all future releases starting with 2.21, and will be the only source of 3.1+ feature releases post-bionic
       ["/var/lib/lxd/devlxd", "/var/snap/lxd/common/lxd/devlxd"].each do |devlxd|
-        if File.exist?(devlxd)
+        if file_exist?(devlxd)
           logger.trace("Plugin Virtualization: #{devlxd} exists. Detecting as lxd host")
           virtualization[:system] = "lxd"
           virtualization[:role] = "host"
diff --git a/lib/ohai/plugins/ohai_time.rb b/lib/ohai/plugins/ohai_time.rb
index 5d0a8592..11069660 100644
--- a/lib/ohai/plugins/ohai_time.rb
+++ b/lib/ohai/plugins/ohai_time.rb
@@ -19,7 +19,7 @@
 Ohai.plugin(:OhaiTime) do
   provides "ohai_time"
 
-  collect_data do
+  collect_data(:default, :target) do
     ohai_time Time.now.to_f
   end
 end
diff --git a/lib/ohai/plugins/os.rb b/lib/ohai/plugins/os.rb
index 565e71a8..9159fa70 100644
--- a/lib/ohai/plugins/os.rb
+++ b/lib/ohai/plugins/os.rb
@@ -37,6 +37,10 @@ Ohai.plugin(:OS) do
     os_version shell_out("sysctl -n kern.osreldate").stdout.split($/)[0]
   end
 
+  collect_data(:target) do
+    os collect_os
+  end
+
   collect_data do
     os collect_os
     os_version kernel[:release]
diff --git a/lib/ohai/plugins/scaleway.rb b/lib/ohai/plugins/scaleway.rb
index 006be6e6..efee560c 100644
--- a/lib/ohai/plugins/scaleway.rb
+++ b/lib/ohai/plugins/scaleway.rb
@@ -26,7 +26,7 @@ Ohai.plugin(:Scaleway) do
   # looks for `scaleway` keyword in kernel command line
   # @return [Boolean] do we have the keyword or not?
   def has_scaleway_cmdline?
-    if ::File.exist?("/proc/cmdline") && /scaleway/.match?(::File.read("/proc/cmdline"))
+    if file_exist?("/proc/cmdline") && /scaleway/.match?(file_read("/proc/cmdline"))
       logger.trace("Plugin Scaleway: has_scaleway_cmdline? == true")
       return true
     end
diff --git a/lib/ohai/plugins/shells.rb b/lib/ohai/plugins/shells.rb
index 1e575150..06d20e6a 100644
--- a/lib/ohai/plugins/shells.rb
+++ b/lib/ohai/plugins/shells.rb
@@ -20,9 +20,9 @@ Ohai.plugin(:Shells) do
   provides "shells"
 
   collect_data do
-    if ::File.exist?("/etc/shells")
+    if file_exist?("/etc/shells")
       shells []
-      ::File.readlines("/etc/shells").each do |line|
+      file_open("/etc/shells").readlines.each do |line|
         # remove carriage returns and skip over comments / empty lines
         shells << line.chomp if line[0] == "/"
       end
diff --git a/lib/ohai/plugins/solaris2/platform.rb b/lib/ohai/plugins/solaris2/platform.rb
index 92aac72f..4de5050f 100644
--- a/lib/ohai/plugins/solaris2/platform.rb
+++ b/lib/ohai/plugins/solaris2/platform.rb
@@ -20,7 +20,7 @@ Ohai.plugin(:Platform) do
   provides "platform", "platform_version", "platform_build", "platform_family"
 
   collect_data(:solaris2) do
-    if File.exist?("/sbin/uname")
+    if file_exist?("/sbin/uname")
       uname_exec = "/sbin/uname"
     else
       uname_exec = "uname"
@@ -35,7 +35,7 @@ Ohai.plugin(:Platform) do
       end
     end
 
-    File.open("/etc/release") do |file|
+    file_open("/etc/release") do |file|
       while ( line = file.gets )
         case line
         when /^.*(SmartOS).*$/
diff --git a/lib/ohai/plugins/solaris2/virtualization.rb b/lib/ohai/plugins/solaris2/virtualization.rb
index 4d7d22ef..8912a091 100644
--- a/lib/ohai/plugins/solaris2/virtualization.rb
+++ b/lib/ohai/plugins/solaris2/virtualization.rb
@@ -34,7 +34,7 @@ Ohai.plugin(:Virtualization) do
 
     # Detect paravirt KVM/QEMU from cpuinfo, report as KVM
     psrinfo_path = Ohai.abs_path( "/usr/sbin/psrinfo" )
-    if File.exist?(psrinfo_path)
+    if file_exist?(psrinfo_path)
       so = shell_out("#{psrinfo_path} -pv")
       if /QEMU Virtual CPU|Common KVM processor|Common 32-bit KVM processor/.match?(so.stdout)
         virtualization[:system] = "kvm"
diff --git a/lib/ohai/plugins/ssh_host_key.rb b/lib/ohai/plugins/ssh_host_key.rb
index 07aae83d..0d31f95c 100644
--- a/lib/ohai/plugins/ssh_host_key.rb
+++ b/lib/ohai/plugins/ssh_host_key.rb
@@ -38,9 +38,9 @@ Ohai.plugin(:SSHHostKey) do
   collect_data do
     keys[:ssh] = Mash.new
 
-    sshd_config = if File.exist?("/etc/ssh/sshd_config")
+    sshd_config = if file_exist?("/etc/ssh/sshd_config")
                     "/etc/ssh/sshd_config"
-                  elsif File.exist?("/etc/sshd_config")
+                  elsif file_exist?("/etc/sshd_config")
                     # Darwin
                     "/etc/sshd_config"
                   else
@@ -49,11 +49,11 @@ Ohai.plugin(:SSHHostKey) do
                   end
 
     if sshd_config
-      File.open(sshd_config) do |conf|
+      file_open(sshd_config) do |conf|
         conf.each_line do |line|
           if /^hostkey\s/i.match?(line)
             pub_file = "#{line.split[1]}.pub"
-            content = IO.read(pub_file).split
+            content = file_read(pub_file).split
             key_type, key_subtype = extract_keytype?(content)
             keys[:ssh]["host_#{key_type}_public"] = content[1] unless key_type.nil?
             keys[:ssh]["host_#{key_type}_type"] = key_subtype unless key_subtype.nil?
@@ -62,22 +62,22 @@ Ohai.plugin(:SSHHostKey) do
       end
     end
 
-    if keys[:ssh][:host_dsa_public].nil? && File.exist?("/etc/ssh/ssh_host_dsa_key.pub")
-      keys[:ssh][:host_dsa_public] = IO.read("/etc/ssh/ssh_host_dsa_key.pub").split[1]
+    if keys[:ssh][:host_dsa_public].nil? && file_exist?("/etc/ssh/ssh_host_dsa_key.pub")
+      keys[:ssh][:host_dsa_public] = file_read("/etc/ssh/ssh_host_dsa_key.pub").split[1]
     end
 
-    if keys[:ssh][:host_rsa_public].nil? && File.exist?("/etc/ssh/ssh_host_rsa_key.pub")
-      keys[:ssh][:host_rsa_public] = IO.read("/etc/ssh/ssh_host_rsa_key.pub").split[1]
+    if keys[:ssh][:host_rsa_public].nil? && file_exist?("/etc/ssh/ssh_host_rsa_key.pub")
+      keys[:ssh][:host_rsa_public] = file_read("/etc/ssh/ssh_host_rsa_key.pub").split[1]
     end
 
-    if keys[:ssh][:host_ecdsa_public].nil? && File.exist?("/etc/ssh/ssh_host_ecdsa_key.pub")
-      content = IO.read("/etc/ssh/ssh_host_ecdsa_key.pub")
+    if keys[:ssh][:host_ecdsa_public].nil? && file_exist?("/etc/ssh/ssh_host_ecdsa_key.pub")
+      content = file_read("/etc/ssh/ssh_host_ecdsa_key.pub")
       keys[:ssh][:host_ecdsa_public] = content.split[1]
       keys[:ssh][:host_ecdsa_type] = content.split[0]
     end
 
-    if keys[:ssh][:host_ed25519_public].nil? && File.exist?("/etc/ssh/ssh_host_ed25519_key.pub")
-      keys[:ssh][:host_ed25519_public] = IO.read("/etc/ssh/ssh_host_ed25519_key.pub").split[1]
+    if keys[:ssh][:host_ed25519_public].nil? && file_exist?("/etc/ssh/ssh_host_ed25519_key.pub")
+      keys[:ssh][:host_ed25519_public] = file_read("/etc/ssh/ssh_host_ed25519_key.pub").split[1]
     end
   end
 end
diff --git a/lib/ohai/plugins/train.rb b/lib/ohai/plugins/train.rb
new file mode 100644
index 00000000..cd0c89bd
--- /dev/null
+++ b/lib/ohai/plugins/train.rb
@@ -0,0 +1,35 @@
+#
+# Copyright:: Copyright (c) Chef Software Inc.
+# License:: Apache License, Version 2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+Ohai.plugin(:Train) do
+  provides "train"
+
+  collect_data do
+    if transport_connection
+      train Mash.new
+      train["family_hierarchy"] = transport_connection.platform.family_hierarchy
+      train["family"] = transport_connection.platform.family
+      train["platform"] = transport_connection.platform.platform
+      train["backend"] = transport_connection.backend_type
+      if transport_connection.respond_to?(:uri)
+        train["scheme"] = URI.parse(transport_connection.uri).scheme
+        train["uri"] = transport_connection.uri
+      else
+      end
+    end
+  end
+end
diff --git a/lib/ohai/plugins/uptime.rb b/lib/ohai/plugins/uptime.rb
index b1f48076..fc24d676 100644
--- a/lib/ohai/plugins/uptime.rb
+++ b/lib/ohai/plugins/uptime.rb
@@ -54,7 +54,7 @@ Ohai.plugin(:Uptime) do
   end
 
   collect_data(:linux) do
-    uptime, idletime = File.open("/proc/uptime").gets.split(" ")
+    uptime, idletime = file_open("/proc/uptime").gets.split(" ")
     uptime_seconds uptime.to_i
     uptime seconds_to_human(uptime.to_i)
     idletime_seconds idletime.to_i
diff --git a/lib/ohai/plugins/vmware.rb b/lib/ohai/plugins/vmware.rb
index 5e2e0b02..edcae742 100644
--- a/lib/ohai/plugins/vmware.rb
+++ b/lib/ohai/plugins/vmware.rb
@@ -41,7 +41,7 @@ Ohai.plugin(:VMware) do
   end
 
   def get_vm_attributes(vmtools_path)
-    if !File.exist?(vmtools_path)
+    if !file_exist?(vmtools_path)
       logger.trace("Plugin VMware: #{vmtools_path} not found")
     else
       vmware Mash.new
diff --git a/lib/ohai/runner.rb b/lib/ohai/runner.rb
index 820495ad..72808d2e 100644
--- a/lib/ohai/runner.rb
+++ b/lib/ohai/runner.rb
@@ -24,6 +24,9 @@ module Ohai
   class Runner
 
     attr_reader :failed_plugins, :logger
+
+    attr_accessor :transport_connection
+
     # safe_run: set to true if this runner will run plugins in
     # safe-mode. default false.
     def initialize(controller, safe_run = false)
@@ -93,6 +96,7 @@ module Ohai
         end
 
         if dependency_providers.empty?
+          next_plugin.transport_connection = transport_connection
           @safe_run ? next_plugin.safe_run : next_plugin.run
           if next_plugin.failed
             @failed_plugins << next_plugin.name
diff --git a/lib/ohai/system.rb b/lib/ohai/system.rb
index ee196414..e78e6bb4 100644
--- a/lib/ohai/system.rb
+++ b/lib/ohai/system.rb
@@ -29,7 +29,9 @@ require_relative "mixin/constant_helper"
 require_relative "provides_map"
 require_relative "hints"
 require_relative "config"
+require_relative "train_transport"
 require "ffi_yajl" unless defined?(FFI_Yajl)
+require "cgi" unless defined?(CGI)
 
 module Ohai
   # The class used by Ohai::Application and Chef to actually collect data
@@ -40,6 +42,7 @@ module Ohai
     attr_reader :config
     attr_reader :provides_map
     attr_reader :logger
+    attr_writer :transport_connection
 
     # the cli flag is used to determine if we're being constructed by
     # something like chef-client (which doesn't set this flag) and
@@ -67,7 +70,6 @@ module Ohai
       configure_logging if @cli
 
       @loader = Ohai::Loader.new(self)
-      @runner = Ohai::Runner.new(self, true)
 
       Ohai::Hints.refresh_hints
 
@@ -75,6 +77,13 @@ module Ohai
       recursive_remove_constants(Ohai::NamedPlugin)
     end
 
+    def runner
+      @runner ||=
+        Ohai::Runner.new(self, true).tap do |runner|
+          runner.transport_connection = transport_connection unless transport_connection.nil?
+        end
+    end
+
     def [](key)
       @data[key]
     end
@@ -102,6 +111,13 @@ module Ohai
       @loader.load_all
     end
 
+    # get backend parameters for target mode
+    #
+    # @return [Train::Transport]
+    def transport_connection
+      @transport_connection ||= Ohai::TrainTransport.new(logger).build_transport&.connection
+    end
+
     # run all plugins or those that match the attribute filter is provided
     #
     # @param safe [Boolean]
@@ -111,13 +127,14 @@ module Ohai
     def run_plugins(safe = false, attribute_filter = nil)
       begin
         @provides_map.all_plugins(attribute_filter).each do |plugin|
-          @runner.run_plugin(plugin)
+          runner.run_plugin(plugin)
         end
+        transport_connection.close unless transport_connection.nil?
       rescue Ohai::Exceptions::AttributeNotFound, Ohai::Exceptions::DependencyCycle => e
         logger.error("Encountered error while running plugins: #{e.inspect}")
         raise
       end
-      critical_failed = Ohai::Config.ohai[:critical_plugins] & @runner.failed_plugins
+      critical_failed = Ohai::Config.ohai[:critical_plugins] & runner.failed_plugins
       unless critical_failed.empty?
         msg = "The following Ohai plugins marked as critical failed: #{critical_failed}"
         if @cli
@@ -139,7 +156,7 @@ module Ohai
     def run_additional_plugins(plugin_path)
       @loader.load_additional(plugin_path).each do |plugin|
         logger.trace "Running plugin #{plugin}"
-        @runner.run_plugin(plugin)
+        runner.run_plugin(plugin)
       end
 
       freeze_strings!
@@ -225,5 +242,16 @@ module Ohai
       end
       visitor.call(@data)
     end
+
+    # Extract additional backend parameters from Target Mode URL.
+    #
+    # @api private
+    # @return [Hash]
+    def backend_parameters
+      uri = URI.parse(config[:target])
+      return {} unless uri.query
+
+      CGI.parse(uri.query).map { |k, v| [k.to_sym, v.first] }.to_h
+    end
   end
 end
diff --git a/lib/ohai/train_transport.rb b/lib/ohai/train_transport.rb
new file mode 100644
index 00000000..366132ac
--- /dev/null
+++ b/lib/ohai/train_transport.rb
@@ -0,0 +1,28 @@
+# Author:: Bryan McLellan <btm@loftninjas.org>
+# Copyright:: Copyright (c) Chef Software Inc.
+# License:: Apache License, Version 2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+require "chef-config/mixin/train_transport" unless defined?(ChefConfig::Mixin::TrainTransport)
+
+module Ohai
+  class TrainTransport
+    include ChefConfig::Mixin::TrainTransport
+
+    def config
+      Ohai::Config
+    end
+  end
+end
diff --git a/ohai.gemspec b/ohai.gemspec
index ce98cb76..95fc2ff8 100644
--- a/ohai.gemspec
+++ b/ohai.gemspec
@@ -11,7 +11,7 @@ Gem::Specification.new do |s|
   s.email = "adam@chef.io"
   s.homepage = "https://github.com/chef/ohai/"
 
-  s.required_ruby_version = ">= 2.5"
+  s.required_ruby_version = ">= 2.6"
 
   s.add_dependency "chef-config", ">= 12.8", "< 17"
   s.add_dependency "chef-utils", ">= 16.0", "< 17"
@@ -24,6 +24,7 @@ Gem::Specification.new do |s|
   s.add_dependency "mixlib-shellout", ">= 2.0", "< 4.0"
   s.add_dependency "plist", "~> 3.1"
   s.add_dependency "wmi-lite", "~> 1.0"
+  s.add_dependency "train-core"
   # Note for ohai developers: If chef-config causes you grief, try:
   #     bundle install --with development
   # this should work as long as chef is a development dependency in Gemfile.
diff --git a/spec/functional/plugins/linux/interrupts_spec.rb b/spec/functional/plugins/linux/interrupts_spec.rb
index 22306cb7..64863586 100644
--- a/spec/functional/plugins/linux/interrupts_spec.rb
+++ b/spec/functional/plugins/linux/interrupts_spec.rb
@@ -26,7 +26,7 @@ describe Ohai::System, "Linux interrupts plugin" do
   end
 
   it "parses smp_affinity (partial mask, all)" do
-    allow(::File).to receive(:read).with("/affinity").and_return("f")
+    allow(plugin).to receive(:file_read).with("/affinity").and_return("f")
     expect(plugin.parse_smp_affinity("/affinity", 2)).to eq({
                                                               0 => true,
                                                               1 => true,
@@ -34,7 +34,7 @@ describe Ohai::System, "Linux interrupts plugin" do
   end
 
   it "parses smp_affinity (partial mask, one)" do
-    allow(::File).to receive(:read).with("/affinity").and_return("e")
+    allow(plugin).to receive(:file_read).with("/affinity").and_return("e")
     expect(plugin.parse_smp_affinity("/affinity", 2)).to eq({
                                                               0 => false,
                                                               1 => true,
@@ -42,7 +42,7 @@ describe Ohai::System, "Linux interrupts plugin" do
   end
 
   it "parses smp_affinity (full mask, all)" do
-    allow(::File).to receive(:read).with("/affinity").and_return("ff")
+    allow(plugin).to receive(:file_read).with("/affinity").and_return("ff")
     expect(plugin.parse_smp_affinity("/affinity", 2)).to eq({
                                                               0 => true,
                                                               1 => true,
@@ -50,7 +50,7 @@ describe Ohai::System, "Linux interrupts plugin" do
   end
 
   it "parses smp_affinity (full mask, one)" do
-    allow(::File).to receive(:read).with("/affinity").and_return("fe")
+    allow(plugin).to receive(:file_read).with("/affinity").and_return("fe")
     expect(plugin.parse_smp_affinity("/affinity", 2)).to eq({
                                                               0 => false,
                                                               1 => true,
@@ -62,7 +62,7 @@ describe Ohai::System, "Linux interrupts plugin" do
     (0..47).each do |i|
       cpus[i] = true
     end
-    allow(::File).to receive(:read).with("/affinity")
+    allow(plugin).to receive(:file_read).with("/affinity")
       .and_return("ffff,ffffffff")
     expect(plugin.parse_smp_affinity("/affinity", 48)).to eq(cpus)
   end
@@ -74,7 +74,7 @@ describe Ohai::System, "Linux interrupts plugin" do
     end
     cpus[12] = false
     cpus[32] = false
-    allow(::File).to receive(:read).with("/affinity")
+    allow(plugin).to receive(:file_read).with("/affinity")
       .and_return("fffe,ffffefff")
     expect(plugin.parse_smp_affinity("/affinity", 48)).to eq(cpus)
   end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 5f7cadfb..70320232 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -22,10 +22,6 @@ end
 
 include Ohai::Mixin::ConstantHelper
 
-if Ohai::Mixin::OS.collect_os == /mswin|mingw32|windows/
-  ENV["PATH"] = ""
-end
-
 def get_plugin(plugin, ohai = Ohai::System.new, path = PLUGIN_PATH)
   loader = Ohai::Loader.new(ohai)
   loader.load_plugin(File.join(path, "#{plugin}.rb"))
diff --git a/spec/unit/dsl/plugin_spec.rb b/spec/unit/dsl/plugin_spec.rb
index 5c73a4a4..d6d4956c 100644
--- a/spec/unit/dsl/plugin_spec.rb
+++ b/spec/unit/dsl/plugin_spec.rb
@@ -521,7 +521,7 @@ describe Ohai::DSL::Plugin::VersionVII do
 
     it "fails a platform has already been defined in the same plugin" do
       Ohai.plugin(:Test) { collect_data {} }
-      expect(Ohai::Log).to receive(:warn).with(/collect_data already defined on platform/).twice
+      expect(Ohai::Log).to receive(:warn).with(/collect_data already defined on os/).twice
       Ohai.plugin(:Test) do
         collect_data {}
         collect_data {}
@@ -530,7 +530,7 @@ describe Ohai::DSL::Plugin::VersionVII do
 
     it "fails if a platform has already been defined in another plugin file" do
       Ohai.plugin(:Test) { collect_data {} }
-      expect(Ohai::Log).to receive(:warn).with(/collect_data already defined on platform/)
+      expect(Ohai::Log).to receive(:warn).with(/collect_data already defined on os/)
       Ohai.plugin(:Test) do
         collect_data {}
       end
diff --git a/spec/unit/loader_spec.rb b/spec/unit/loader_spec.rb
index 9275b5e6..d7915bd3 100644
--- a/spec/unit/loader_spec.rb
+++ b/spec/unit/loader_spec.rb
@@ -130,7 +130,7 @@ describe Ohai::Loader do
 
       describe "when the plugin defines collect_data on the same platform more than once" do
         it "shoud log an illegal plugin definition warning" do
-          expect(Ohai::Log).to receive(:warn).with(/collect_data already defined on platform/)
+          expect(Ohai::Log).to receive(:warn).with(/collect_data already defined on os/)
           loader.load_plugin(path_to("illegal_def.rb"))
         end
 
diff --git a/spec/unit/mixin/shell_out_spec.rb b/spec/unit/mixin/shell_out_spec.rb
index 35873e04..76e2e178 100644
--- a/spec/unit/mixin/shell_out_spec.rb
+++ b/spec/unit/mixin/shell_out_spec.rb
@@ -28,8 +28,11 @@ describe Ohai::Mixin::ShellOut, "shell_out" do
   let(:timeout) { 30 }
 
   let(:options) do
+    path_var = windows? ? "Path" : "PATH"
+
     # this just replicates the behavior of default_paths in chef-utils
-    default_paths = [ Gem.bindir, RbConfig::CONFIG["bindir"] ].compact.uniq
+    split_path = instance.send(:__env_path).split(File::PATH_SEPARATOR)
+    default_paths = [ RbConfig::CONFIG["bindir"], Gem.bindir, split_path ].flatten.compact.uniq
 
     if windows?
       default_paths = default_paths.join(";")
@@ -37,8 +40,6 @@ describe Ohai::Mixin::ShellOut, "shell_out" do
       default_paths = ( default_paths + [ "/usr/local/sbin", "/usr/local/bin", "/usr/sbin", "/usr/bin", "/sbin", "/bin" ] ).compact.uniq.join(":")
     end
 
-    path_var = windows? ? "Path" : "PATH"
-
     default_locale = ChefConfig::Config.guess_internal_locale
     {
       timeout: timeout,
@@ -55,6 +56,9 @@ describe Ohai::Mixin::ShellOut, "shell_out" do
 
   class DummyPlugin
     include Ohai::Mixin::ShellOut
+    def transport_connection
+      nil
+    end
   end
 
   let(:instance) { DummyPlugin.new }
@@ -73,64 +77,33 @@ describe Ohai::Mixin::ShellOut, "shell_out" do
 
   describe "when the command runs" do
     it "logs the command and exitstatus" do
-      expect(Mixlib::ShellOut)
-        .to receive(:new)
-        .with(cmd, options)
-        .and_return(shell_out)
-
-      expect(shell_out)
-        .to receive(:run_command)
-
-      expect(shell_out)
-        .to receive(:exitstatus)
-        .and_return(256)
-
+      expect(Mixlib::ShellOut).to receive(:new).with(cmd, options).and_return(shell_out)
+      expect(shell_out).to receive(:run_command)
+      expect(shell_out).to receive(:exitstatus).and_return(256)
       expect(logger).to receive(:trace)
         .with("Plugin OSSparkleDream: ran 'sparkle-dream --version' and returned 256")
-
       instance.shell_out(cmd)
     end
   end
 
   describe "when the command does not exist" do
     it "logs the command and error message" do
-      expect(Mixlib::ShellOut)
-        .to receive(:new)
-        .with(cmd, options)
-        .and_return(shell_out)
-
-      expect(shell_out)
-        .to receive(:run_command)
-        .and_raise(Errno::ENOENT, "sparkle-dream")
-
-      expect(logger)
-        .to receive(:trace)
+      expect(Mixlib::ShellOut).to receive(:new).with(cmd, options).and_return(shell_out)
+      expect(shell_out).to receive(:run_command).and_raise(Errno::ENOENT, "sparkle-dream")
+      expect(logger).to receive(:trace)
         .with("Plugin OSSparkleDream: ran 'sparkle-dream --version' and failed " \
               "#<Errno::ENOENT: No such file or directory - sparkle-dream>")
-
-      expect { instance.shell_out(cmd) }
-        .to raise_error(Ohai::Exceptions::Exec)
+      expect { instance.shell_out(cmd) }.to raise_error(Ohai::Exceptions::Exec)
     end
   end
 
   describe "when the command times out" do
     it "logs the command an timeout error message" do
-      expect(Mixlib::ShellOut)
-        .to receive(:new)
-        .with(cmd, options)
-        .and_return(shell_out)
-
-      expect(shell_out)
-        .to receive(:run_command)
-        .and_raise(Mixlib::ShellOut::CommandTimeout)
-
-      expect(logger)
-        .to receive(:trace)
-        .with("Plugin OSSparkleDream: ran 'sparkle-dream --version' and timed " \
-              "out after 30 seconds")
-
-      expect { instance.shell_out(cmd) }
-        .to raise_error(Ohai::Exceptions::Exec)
+      expect(Mixlib::ShellOut).to receive(:new).with(cmd, options).and_return(shell_out)
+      expect(shell_out).to receive(:run_command).and_raise(Mixlib::ShellOut::CommandTimeout)
+      expect(logger).to receive(:trace)
+        .with("Plugin OSSparkleDream: ran 'sparkle-dream --version' and timed out after 30 seconds")
+      expect { instance.shell_out(cmd) }.to raise_error(Ohai::Exceptions::Exec)
     end
   end
 
@@ -138,42 +111,21 @@ describe Ohai::Mixin::ShellOut, "shell_out" do
     let(:timeout) { 10 }
 
     it "runs the command with the provided timeout" do
-      expect(Mixlib::ShellOut)
-        .to receive(:new)
-        .with(cmd, options)
-        .and_return(shell_out)
-
-      expect(shell_out)
-        .to receive(:run_command)
-
-      expect(shell_out)
-        .to receive(:exitstatus)
-        .and_return(256)
-
+      expect(Mixlib::ShellOut).to receive(:new).with(cmd, options).and_return(shell_out)
+      expect(shell_out).to receive(:run_command)
+      expect(shell_out).to receive(:exitstatus).and_return(256)
       expect(logger).to receive(:trace)
         .with("Plugin OSSparkleDream: ran 'sparkle-dream --version' and returned 256")
-
       instance.shell_out(cmd, timeout: 10)
     end
 
     describe "when the command times out" do
       it "logs the command an timeout error message" do
-        expect(Mixlib::ShellOut)
-          .to receive(:new)
-          .with(cmd, options)
-          .and_return(shell_out)
-
-        expect(shell_out)
-          .to receive(:run_command)
-          .and_raise(Mixlib::ShellOut::CommandTimeout)
-
-        expect(logger)
-          .to receive(:trace)
-          .with("Plugin OSSparkleDream: ran 'sparkle-dream --version' and timed " \
-                "out after 10 seconds")
-
-        expect { instance.shell_out(cmd, timeout: 10) }
-          .to raise_error(Ohai::Exceptions::Exec)
+        expect(Mixlib::ShellOut).to receive(:new).with(cmd, options).and_return(shell_out)
+        expect(shell_out).to receive(:run_command).and_raise(Mixlib::ShellOut::CommandTimeout)
+        expect(logger).to receive(:trace)
+          .with("Plugin OSSparkleDream: ran 'sparkle-dream --version' and timed out after 10 seconds")
+        expect { instance.shell_out(cmd, timeout: 10) }.to raise_error(Ohai::Exceptions::Exec)
       end
     end
   end
diff --git a/spec/unit/mixin/which_spec.rb b/spec/unit/mixin/which_spec.rb
index d6236757..c1d4c661 100644
--- a/spec/unit/mixin/which_spec.rb
+++ b/spec/unit/mixin/which_spec.rb
@@ -20,19 +20,20 @@ require "spec_helper"
 
 class FileHelperMock
   include Ohai::Mixin::Which
+  def transport_connection
+    nil
+  end
 end
 
 describe "Ohai::Mixin::Which" do
   let(:file_helper) { FileHelperMock.new }
 
   before do
-    old_env = ENV
-    ENV["Path"] = ENV["PATH"] = "/usr/bin"
+    Ohai::Mixin::ChefUtilsWiring::PathCache.instance.path_cache = "/usr/bin"
     allow(file_helper).to receive(:name).and_return("Fakeclass")
     logger = instance_double("Mixlib::Log::Child", trace: nil, debug: nil, warn: nil)
     allow(file_helper).to receive(:logger).and_return(logger)
     allow(File).to receive(:executable?).and_return(false)
-    ENV = old_env
   end
 
   describe "which" do
diff --git a/spec/unit/plugins/azure_spec.rb b/spec/unit/plugins/azure_spec.rb
index 86e8ec86..1ddfe3d1 100644
--- a/spec/unit/plugins/azure_spec.rb
+++ b/spec/unit/plugins/azure_spec.rb
@@ -134,9 +134,9 @@ describe Ohai::System, "plugin azure" do
   describe "without azure hint file or agent or dhcp options" do
     before do
       allow(plugin).to receive(:hint?).with("azure").and_return(false)
-      allow(File).to receive(:exist?).with("/usr/sbin/waagent").and_return(false)
-      allow(Dir).to receive(:exist?).with('C:\WindowsAzure').and_return(false)
-      allow(File).to receive(:exist?).with("/var/lib/dhcp/dhclient.eth0.leases").and_return(true)
+      allow(plugin).to receive(:file_exist?).with("/usr/sbin/waagent").and_return(false)
+      allow(plugin).to receive(:dir_exist?).with('C:\WindowsAzure').and_return(false)
+      allow(plugin).to receive(:file_exist?).with("/var/lib/dhcp/dhclient.eth0.leases").and_return(true)
       @double_file = double("/var/lib/dhcp/dhclient.eth0.leases")
       allow(@double_file).to receive(:each)
         .and_yield("lease {")
@@ -158,7 +158,7 @@ describe Ohai::System, "plugin azure" do
         .and_yield("  rebind 2 2016/03/01 13:22:07;")
         .and_yield("  expire 2 2016/03/01 16:40:56;")
         .and_yield("}")
-      allow(File).to receive(:open).with("/var/lib/dhcp/dhclient.eth0.leases").and_return(@double_file)
+      allow(plugin).to receive(:file_open).with("/var/lib/dhcp/dhclient.eth0.leases").and_return(@double_file)
     end
 
     it_behaves_like "!azure"
@@ -168,9 +168,9 @@ describe Ohai::System, "plugin azure" do
     before do
       allow(plugin).to receive(:hint?).with("rackspace").and_return(true)
       allow(plugin).to receive(:hint?).with("azure").and_return(false)
-      allow(File).to receive(:exist?).with("/usr/sbin/waagent").and_return(false)
-      allow(Dir).to receive(:exist?).with('C:\WindowsAzure').and_return(false)
-      allow(File).to receive(:exist?).with("/var/lib/dhcp/dhclient.eth0.leases").and_return(false)
+      allow(plugin).to receive(:file_exist?).with("/usr/sbin/waagent").and_return(false)
+      allow(plugin).to receive(:dir_exist?).with('C:\WindowsAzure').and_return(false)
+      allow(plugin).to receive(:file_exist?).with("/var/lib/dhcp/dhclient.eth0.leases").and_return(false)
     end
 
     it_behaves_like "!azure"
@@ -179,8 +179,8 @@ describe Ohai::System, "plugin azure" do
   describe "without azure hint file but with agent on linux" do
     before do
       allow(plugin).to receive(:hint?).with("azure").and_return(false)
-      allow(File).to receive(:exist?).with("/usr/sbin/waagent").and_return(true)
-      allow(Dir).to receive(:exist?).with('C:\WindowsAzure').and_return(false)
+      allow(plugin).to receive(:file_exist?).with("/usr/sbin/waagent").and_return(true)
+      allow(plugin).to receive(:dir_exist?).with('C:\WindowsAzure').and_return(false)
     end
 
     it_behaves_like "azure"
@@ -189,8 +189,8 @@ describe Ohai::System, "plugin azure" do
   describe "without azure hint file but with agent on windows" do
     before do
       allow(plugin).to receive(:hint?).with("azure").and_return(false)
-      allow(File).to receive(:exist?).with("/usr/sbin/waagent").and_return(false)
-      allow(Dir).to receive(:exist?).with('C:\WindowsAzure').and_return(true)
+      allow(plugin).to receive(:file_exist?).with("/usr/sbin/waagent").and_return(false)
+      allow(plugin).to receive(:dir_exist?).with('C:\WindowsAzure').and_return(true)
     end
 
     it_behaves_like "azure"
@@ -199,9 +199,9 @@ describe Ohai::System, "plugin azure" do
   describe "without azure hint or agent but with dhcp option" do
     before do
       allow(plugin).to receive(:hint?).with("azure").and_return(false)
-      allow(File).to receive(:exist?).with("/usr/sbin/waagent").and_return(false)
-      allow(Dir).to receive(:exist?).with('C:\WindowsAzure').and_return(false)
-      allow(File).to receive(:exist?).with("/var/lib/dhcp/dhclient.eth0.leases").and_return(true)
+      allow(plugin).to receive(:file_exist?).with("/usr/sbin/waagent").and_return(false)
+      allow(plugin).to receive(:dir_exist?).with('C:\WindowsAzure').and_return(false)
+      allow(plugin).to receive(:file_exist?).with("/var/lib/dhcp/dhclient.eth0.leases").and_return(true)
       @double_file = double("/var/lib/dhcp/dhclient.eth0.leases")
       allow(@double_file).to receive(:each)
         .and_yield("lease {")
@@ -223,7 +223,7 @@ describe Ohai::System, "plugin azure" do
         .and_yield("  rebind 5 2152/03/10 09:03:39;")
         .and_yield("  expire 5 2152/03/10 09:03:39;")
         .and_yield("}")
-      allow(File).to receive(:open).with("/var/lib/dhcp/dhclient.eth0.leases").and_return(@double_file)
+      allow(plugin).to receive(:file_open).with("/var/lib/dhcp/dhclient.eth0.leases").and_return(@double_file)
     end
 
     it_behaves_like "azure"
diff --git a/spec/unit/plugins/ec2_spec.rb b/spec/unit/plugins/ec2_spec.rb
index d3e6e3d6..e1641b89 100644
--- a/spec/unit/plugins/ec2_spec.rb
+++ b/spec/unit/plugins/ec2_spec.rb
@@ -25,9 +25,9 @@ describe Ohai::System, "plugin ec2" do
 
   before do
     allow(plugin).to receive(:hint?).with("ec2").and_return(false)
-    allow(File).to receive(:exist?).with("/sys/hypervisor/uuid").and_return(false)
-    allow(File).to receive(:exist?).with("/sys/class/dmi/id/bios_vendor").and_return(false)
-    allow(File).to receive(:exist?).with("/sys/class/dmi/id/bios_version").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/sys/hypervisor/uuid").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/sys/class/dmi/id/bios_vendor").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/sys/class/dmi/id/bios_version").and_return(false)
   end
 
   shared_examples_for "!ec2" do
@@ -334,8 +334,8 @@ describe Ohai::System, "plugin ec2" do
 
   describe "with amazon dmi bios version data" do
     before do
-      allow(File).to receive(:exist?).with("/sys/class/dmi/id/bios_version").and_return(true)
-      allow(File).to receive(:read).with("/sys/class/dmi/id/bios_version").and_return("4.2.amazon\n")
+      allow(plugin).to receive(:file_exist?).with("/sys/class/dmi/id/bios_version").and_return(true)
+      allow(plugin).to receive(:file_read).with("/sys/class/dmi/id/bios_version").and_return("4.2.amazon\n")
     end
 
     it_behaves_like "ec2"
@@ -344,8 +344,8 @@ describe Ohai::System, "plugin ec2" do
 
   describe "with non-amazon dmi bios version data" do
     before do
-      allow(File).to receive(:exist?).with("/sys/class/dmi/id/bios_version").and_return(true)
-      allow(File).to receive(:read).with("/sys/class/dmi/id/bios_version").and_return("1.0\n")
+      allow(plugin).to receive(:file_exist?).with("/sys/class/dmi/id/bios_version").and_return(true)
+      allow(plugin).to receive(:file_read).with("/sys/class/dmi/id/bios_version").and_return("1.0\n")
     end
 
     it_behaves_like "!ec2"
@@ -354,8 +354,8 @@ describe Ohai::System, "plugin ec2" do
 
   describe "with amazon dmi bios vendor data" do
     before do
-      allow(File).to receive(:exist?).with("/sys/class/dmi/id/bios_vendor").and_return(true)
-      allow(File).to receive(:read).with("/sys/class/dmi/id/bios_vendor").and_return("Amazon EC2\n")
+      allow(plugin).to receive(:file_exist?).with("/sys/class/dmi/id/bios_vendor").and_return(true)
+      allow(plugin).to receive(:file_read).with("/sys/class/dmi/id/bios_vendor").and_return("Amazon EC2\n")
     end
 
     it_behaves_like "ec2"
@@ -364,8 +364,8 @@ describe Ohai::System, "plugin ec2" do
 
   describe "with non-amazon dmi bios vendor data" do
     before do
-      allow(File).to receive(:exist?).with("/sys/class/dmi/id/bios_vendor").and_return(true)
-      allow(File).to receive(:read).with("/sys/class/dmi/id/bios_vendor").and_return("Xen\n")
+      allow(plugin).to receive(:file_exist?).with("/sys/class/dmi/id/bios_vendor").and_return(true)
+      allow(plugin).to receive(:file_read).with("/sys/class/dmi/id/bios_vendor").and_return("Xen\n")
     end
 
     it_behaves_like "!ec2"
@@ -374,8 +374,8 @@ describe Ohai::System, "plugin ec2" do
 
   describe "with EC2 Xen UUID" do
     before do
-      allow(File).to receive(:exist?).with("/sys/hypervisor/uuid").and_return(true)
-      allow(File).to receive(:read).with("/sys/hypervisor/uuid").and_return("ec2a0561-e4d6-8e15-d9c8-2e0e03adcde8\n")
+      allow(plugin).to receive(:file_exist?).with("/sys/hypervisor/uuid").and_return(true)
+      allow(plugin).to receive(:file_read).with("/sys/hypervisor/uuid").and_return("ec2a0561-e4d6-8e15-d9c8-2e0e03adcde8\n")
     end
 
     it_behaves_like "ec2"
@@ -384,8 +384,8 @@ describe Ohai::System, "plugin ec2" do
 
   describe "with non-EC2 Xen UUID" do
     before do
-      allow(File).to receive(:exist?).with("/sys/hypervisor/uuid").and_return(true)
-      allow(File).to receive(:read).with("/sys/hypervisor/uuid").and_return("123a0561-e4d6-8e15-d9c8-2e0e03adcde8\n")
+      allow(plugin).to receive(:file_exist?).with("/sys/hypervisor/uuid").and_return(true)
+      allow(plugin).to receive(:file_read).with("/sys/hypervisor/uuid").and_return("123a0561-e4d6-8e15-d9c8-2e0e03adcde8\n")
     end
 
     it_behaves_like "!ec2"
diff --git a/spec/unit/plugins/joyent_spec.rb b/spec/unit/plugins/joyent_spec.rb
index 516cd90e..b62aae5f 100644
--- a/spec/unit/plugins/joyent_spec.rb
+++ b/spec/unit/plugins/joyent_spec.rb
@@ -74,8 +74,8 @@ describe Ohai::System, "plugin joyent" do
           VERIFIED_INSTALLATION=trusted
         EOS
 
-        allow(::File).to receive(:read).with("/etc/product").and_return(etc_product)
-        allow(::File).to receive(:read).with("/opt/local/etc/pkg_install.conf").and_return(pkg_install_conf)
+        allow(plugin).to receive(:file_read).with("/etc/product").and_return(etc_product)
+        allow(plugin).to receive(:file_read).with("/opt/local/etc/pkg_install.conf").and_return(pkg_install_conf)
         plugin.run
       end
 
diff --git a/spec/unit/plugins/linux/block_device_spec.rb b/spec/unit/plugins/linux/block_device_spec.rb
index 9a75c12f..ce273b92 100644
--- a/spec/unit/plugins/linux/block_device_spec.rb
+++ b/spec/unit/plugins/linux/block_device_spec.rb
@@ -46,7 +46,7 @@ describe Ohai::System, "Linux Block Device Plugin" do
     allow(@plugin).to receive(:collect_os).and_return(:linux)
 
     allow(File).to receive(:exist?).with("/sys/block").and_return(true)
-    allow(Dir).to receive(:[]).with("/sys/block/*") do
+    allow(@plugin).to receive(:dir_glob).with("/sys/block/*") do
       DISKS.collect { |disk, _files| "/sys/block/#{disk}" }
     end
 
diff --git a/spec/unit/plugins/linux/interrupts_spec.rb b/spec/unit/plugins/linux/interrupts_spec.rb
index abed19e0..4ff1dec3 100644
--- a/spec/unit/plugins/linux/interrupts_spec.rb
+++ b/spec/unit/plugins/linux/interrupts_spec.rb
@@ -549,12 +549,12 @@ describe Ohai::System, "Linux interrupts plugin" do
     plugin[:cpu] = {
       "total" => 4,
     }
-    allow(File).to receive(:exist?).and_return(false)
-    allow(File).to receive(:open).with("/proc/interrupts").and_return(@proc_interrupts)
-    allow(File).to receive(:exist?).with("/proc/irq/default_smp_affinity").and_return(true)
-    allow(File).to receive(:read).with("/proc/irq/default_smp_affinity").and_return("ff")
-    allow(File).to receive(:exist?).with("/proc/irq/1/smp_affinity").and_return(true)
-    allow(File).to receive(:read).with("/proc/irq/1/smp_affinity").and_return("ff")
+    allow(plugin).to receive(:file_exist?).and_return(false)
+    allow(plugin).to receive(:file_open).with("/proc/interrupts").and_return(@proc_interrupts)
+    allow(plugin).to receive(:file_exist?).with("/proc/irq/default_smp_affinity").and_return(true)
+    allow(plugin).to receive(:file_read).with("/proc/irq/default_smp_affinity").and_return("ff")
+    allow(plugin).to receive(:file_exist?).with("/proc/irq/1/smp_affinity").and_return(true)
+    allow(plugin).to receive(:file_read).with("/proc/irq/1/smp_affinity").and_return("ff")
     plugin.run
     expect(plugin[:interrupts]).to eq(interrupts)
   end
diff --git a/spec/unit/plugins/linux/kernel_spec.rb b/spec/unit/plugins/linux/kernel_spec.rb
index 2a1446b2..74ba6f43 100644
--- a/spec/unit/plugins/linux/kernel_spec.rb
+++ b/spec/unit/plugins/linux/kernel_spec.rb
@@ -56,8 +56,8 @@ describe Ohai::System, "Linux kernel plugin" do
     allow(@plugin).to receive(:shell_out).with("uname -o").and_return(mock_shell_out(0, "Linux", ""))
     allow(@plugin).to receive(:shell_out).with("env lsmod").and_return(mock_shell_out(0, @env_lsmod, ""))
     @version_module.each do |mod, vers|
-      allow(File).to receive(:exist?).with("/sys/module/#{mod}/version").and_return(true)
-      allow(File).to receive(:read).with("/sys/module/#{mod}/version").and_return(vers)
+      allow(@plugin).to receive(:file_exist?).with("/sys/module/#{mod}/version").and_return(true)
+      allow(@plugin).to receive(:file_read).with("/sys/module/#{mod}/version").and_return(vers)
     end
     expect(@plugin).to receive(:shell_out).with("env lsmod").at_least(:once)
     @plugin.run
diff --git a/spec/unit/plugins/linux/machineid_spec.rb b/spec/unit/plugins/linux/machineid_spec.rb
index e751def0..cb668ebf 100644
--- a/spec/unit/plugins/linux/machineid_spec.rb
+++ b/spec/unit/plugins/linux/machineid_spec.rb
@@ -28,8 +28,8 @@ describe Ohai::System, "Machine id plugin" do
   it "reads /etc/machine-id if available" do
     machine_id = "6f702523e2fc7499eb1dc68e5314dacf"
 
-    allow(::File).to receive(:exist?).with("/etc/machine-id").and_return(true)
-    allow(::File).to receive(:read).with("/etc/machine-id").and_return(machine_id)
+    allow(plugin).to receive(:file_exist?).with("/etc/machine-id").and_return(true)
+    allow(plugin).to receive(:file_read).with("/etc/machine-id").and_return(machine_id)
     plugin.run
     expect(plugin[:machine_id]).to eq(machine_id)
   end
@@ -37,9 +37,9 @@ describe Ohai::System, "Machine id plugin" do
   it "reads /var/lib/dbus/machine-id if available" do
     machine_id = "6f702523e2fc7499eb1dc68e5314dacf"
 
-    allow(::File).to receive(:exist?).with("/etc/machine-id").and_return(false)
-    allow(::File).to receive(:exist?).with("/var/lib/dbus/machine-id").and_return(true)
-    allow(::File).to receive(:read).with("/var/lib/dbus/machine-id").and_return(machine_id)
+    allow(plugin).to receive(:file_exist?).with("/etc/machine-id").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/var/lib/dbus/machine-id").and_return(true)
+    allow(plugin).to receive(:file_read).with("/var/lib/dbus/machine-id").and_return(machine_id)
     plugin.run
     expect(plugin[:machine_id]).to eq(machine_id)
   end
diff --git a/spec/unit/plugins/linux/platform_spec.rb b/spec/unit/plugins/linux/platform_spec.rb
index b482574a..520a5a26 100644
--- a/spec/unit/plugins/linux/platform_spec.rb
+++ b/spec/unit/plugins/linux/platform_spec.rb
@@ -25,13 +25,13 @@ describe Ohai::System, "Linux plugin platform" do
     let(:file_contents) { "COW=MOO\nDOG=\"BARK\"" }
 
     it "returns nil if the file does not exist" do
-      allow(File).to receive(:exist?).with("/etc/test-release").and_return(false)
+      allow(plugin).to receive(:file_exist?).with("/etc/test-release").and_return(false)
       expect(plugin.read_os_release_info("/etc/test-release")).to be nil
     end
 
     it "returns a hash of expected contents" do
-      allow(File).to receive(:exist?).with("/etc/test-release").and_return(true)
-      allow(File).to receive(:read).with("/etc/test-release").and_return(file_contents)
+      allow(plugin).to receive(:file_exist?).with("/etc/test-release").and_return(true)
+      allow(plugin).to receive(:file_read).with("/etc/test-release").and_return(file_contents)
       release_info = plugin.read_os_release_info("/etc/test-release")
 
       expect(release_info["COW"]).to eq("MOO")
@@ -44,7 +44,7 @@ describe Ohai::System, "Linux plugin platform" do
       let(:release_info) { { "ID" => "os_id" } }
 
       before do
-        allow(File).to receive(:exist?).with("/etc/os-release").and_return(true)
+        allow(plugin).to receive(:file_exist?).with("/etc/os-release").and_return(true)
         allow(plugin).to receive(:read_os_release_info).with("/etc/os-release").and_return(release_info)
       end
 
@@ -63,8 +63,8 @@ describe Ohai::System, "Linux plugin platform" do
       let(:cisco_release_info) { { "ID" => "cisco_id" } }
 
       before do
-        allow(File).to receive(:exist?).with("/etc/os-release").and_return(true)
-        allow(File).to receive(:exist?).with("/etc/cisco-release").and_return(true)
+        allow(plugin).to receive(:file_exist?).with("/etc/os-release").and_return(true)
+        allow(plugin).to receive(:file_exist?).with("/etc/cisco-release").and_return(true)
         allow(plugin).to receive(:read_os_release_info).with("/etc/os-release").and_return(release_info)
         allow(plugin).to receive(:read_os_release_info).with("/etc/cisco-release").and_return(cisco_release_info)
       end
@@ -160,10 +160,10 @@ describe Ohai::System, "Linux plugin platform" do
       end
 
       it "returns nexus_centos for centos os-release id" do
-        expect(File).to receive(:exist?).at_least(:once).with("/etc/shared/os-release").and_return(true)
-        expect(File).to receive(:exist?).at_least(:once).with("/etc/os-release").and_return(true)
-        expect(File).to receive(:read).with("/etc/os-release").and_return(os_release_content)
-        expect(File).to receive(:read).with("/etc/shared/os-release").and_return(cisco_release_content)
+        expect(plugin).to receive(:file_exist?).at_least(:once).with("/etc/shared/os-release").and_return(true)
+        expect(plugin).to receive(:file_exist?).at_least(:once).with("/etc/os-release").and_return(true)
+        expect(plugin).to receive(:file_read).with("/etc/os-release").and_return(os_release_content)
+        expect(plugin).to receive(:file_read).with("/etc/shared/os-release").and_return(cisco_release_content)
         expect(plugin.platform_id_remap("centos")).to eq("nexus_centos")
       end
     end
@@ -214,7 +214,7 @@ describe Ohai::System, "Linux plugin platform" do
   describe "on system with /etc/os-release" do
     before do
       allow(plugin).to receive(:collect_os).and_return(:linux)
-      allow(::File).to receive(:exist?).with("/etc/os-release").and_return(true)
+      allow(plugin).to receive(:file_exist?).with("/etc/os-release").and_return(true)
     end
 
     context "when os-release data is correct" do
@@ -230,7 +230,7 @@ describe Ohai::System, "Linux plugin platform" do
       end
 
       before do
-        expect(File).to receive(:read).with("/etc/os-release").and_return(os_data)
+        expect(plugin).to receive(:file_read).with("/etc/os-release").and_return(os_data)
       end
 
       it "sets platform, platform_family, and platform_version from os-release" do
@@ -252,7 +252,7 @@ describe Ohai::System, "Linux plugin platform" do
       end
 
       before do
-        expect(File).to receive(:read).with("/etc/os-release").and_return(os_data)
+        expect(plugin).to receive(:file_read).with("/etc/os-release").and_return(os_data)
       end
 
       it "sets platform_version using kernel version from uname" do
@@ -277,7 +277,7 @@ describe Ohai::System, "Linux plugin platform" do
       end
 
       before do
-        expect(File).to receive(:read).with("/etc/os-release").and_return(os_data)
+        expect(plugin).to receive(:file_read).with("/etc/os-release").and_return(os_data)
       end
 
       it "sets platform, platform_family, and platform_version from os-release" do
@@ -301,8 +301,8 @@ describe Ohai::System, "Linux plugin platform" do
       end
 
       before do
-        expect(File).to receive(:read).with("/etc/os-release").and_return(os_data)
-        expect(File).to receive(:read).with("/etc/redhat-release").and_return("CentOS Linux release 7.5.1804 (Core)")
+        expect(plugin).to receive(:file_read).with("/etc/os-release").and_return(os_data)
+        expect(plugin).to receive(:file_read).with("/etc/redhat-release").and_return("CentOS Linux release 7.5.1804 (Core)")
       end
 
       it "sets platform, platform_family, and platform_version from os-release" do
@@ -334,22 +334,22 @@ describe Ohai::System, "Linux plugin platform" do
     before do
       allow(plugin).to receive(:collect_os).and_return(:linux)
       plugin[:lsb] = Mash.new
-      allow(File).to receive(:exist?).with("/etc/debian_version").and_return(have_debian_version)
-      allow(File).to receive(:exist?).with("/etc/redhat-release").and_return(have_redhat_release)
-      allow(File).to receive(:exist?).with("/etc/exherbo-release").and_return(have_exherbo_release)
-      allow(File).to receive(:exist?).with("/etc/Eos-release").and_return(have_eos_release)
-      allow(File).to receive(:exist?).with("/etc/SuSE-release").and_return(have_suse_release)
-      allow(File).to receive(:exist?).with("/etc/system-release").and_return(have_system_release)
-      allow(File).to receive(:exist?).with("/etc/slackware-version").and_return(have_slackware_version)
-      allow(File).to receive(:exist?).with("/etc/enterprise-release").and_return(have_enterprise_release)
-      allow(File).to receive(:exist?).with("/etc/oracle-release").and_return(have_oracle_release)
-      allow(File).to receive(:exist?).with("/etc/parallels-release").and_return(have_parallels_release)
-      allow(File).to receive(:exist?).with("/etc/os-release").and_return(have_os_release)
-      allow(File).to receive(:exist?).with("/etc/f5-release").and_return(have_f5_release)
-      allow(File).to receive(:exist?).with("/usr/lib/os-release").and_return(have_usr_lib_os_release)
-      allow(File).to receive(:exist?).with("/etc/shared/os-release").and_return(have_cisco_release)
-
-      allow(File).to receive(:read).with("PLEASE STUB ALL File.read CALLS")
+      allow(plugin).to receive(:file_exist?).with("/etc/debian_version").and_return(have_debian_version)
+      allow(plugin).to receive(:file_exist?).with("/etc/redhat-release").and_return(have_redhat_release)
+      allow(plugin).to receive(:file_exist?).with("/etc/exherbo-release").and_return(have_exherbo_release)
+      allow(plugin).to receive(:file_exist?).with("/etc/Eos-release").and_return(have_eos_release)
+      allow(plugin).to receive(:file_exist?).with("/etc/SuSE-release").and_return(have_suse_release)
+      allow(plugin).to receive(:file_exist?).with("/etc/system-release").and_return(have_system_release)
+      allow(plugin).to receive(:file_exist?).with("/etc/slackware-version").and_return(have_slackware_version)
+      allow(plugin).to receive(:file_exist?).with("/etc/enterprise-release").and_return(have_enterprise_release)
+      allow(plugin).to receive(:file_exist?).with("/etc/oracle-release").and_return(have_oracle_release)
+      allow(plugin).to receive(:file_exist?).with("/etc/parallels-release").and_return(have_parallels_release)
+      allow(plugin).to receive(:file_exist?).with("/etc/os-release").and_return(have_os_release)
+      allow(plugin).to receive(:file_exist?).with("/etc/f5-release").and_return(have_f5_release)
+      allow(plugin).to receive(:file_exist?).with("/usr/lib/os-release").and_return(have_usr_lib_os_release)
+      allow(plugin).to receive(:file_exist?).with("/etc/shared/os-release").and_return(have_cisco_release)
+
+      allow(plugin).to receive(:file_read).with("PLEASE STUB ALL plugin.read CALLS")
     end
 
     describe "on lsb compliant distributions" do
@@ -423,13 +423,13 @@ describe Ohai::System, "Linux plugin platform" do
       end
 
       it "reads the version from /etc/debian_version" do
-        expect(File).to receive(:read).with("/etc/debian_version").and_return("9.5")
+        expect(plugin).to receive(:file_read).with("/etc/debian_version").and_return("9.5")
         plugin.run
         expect(plugin[:platform_version]).to eq("9.5")
       end
 
       it "correctlies strip any newlines" do
-        expect(File).to receive(:read).with("/etc/debian_version").and_return("9.5\n")
+        expect(plugin).to receive(:file_read).with("/etc/debian_version").and_return("9.5\n")
         plugin.run
         expect(plugin[:platform_version]).to eq("9.5")
       end
@@ -452,14 +452,14 @@ describe Ohai::System, "Linux plugin platform" do
       end
 
       it "sets platform and platform_family to slackware" do
-        expect(File).to receive(:read).with("/etc/slackware-version").and_return("Slackware 12.0.0")
+        expect(plugin).to receive(:file_read).with("/etc/slackware-version").and_return("Slackware 12.0.0")
         plugin.run
         expect(plugin[:platform]).to eq("slackware")
         expect(plugin[:platform_family]).to eq("slackware")
       end
 
       it "sets platform_version on slackware" do
-        expect(File).to receive(:read).with("/etc/slackware-version").and_return("Slackware 12.0.0")
+        expect(plugin).to receive(:file_read).with("/etc/slackware-version").and_return("Slackware 12.0.0")
         plugin.run
         expect(plugin[:platform_version]).to eq("12.0.0")
       end
@@ -476,7 +476,7 @@ describe Ohai::System, "Linux plugin platform" do
       end
 
       it "sets platform to arista_eos" do
-        expect(File).to receive(:read).with("/etc/Eos-release").and_return("Arista Networks EOS 4.21.1.1F")
+        expect(plugin).to receive(:file_read).with("/etc/Eos-release").and_return("Arista Networks EOS 4.21.1.1F")
         plugin.run
         expect(plugin[:platform]).to eq("arista_eos")
         expect(plugin[:platform_family]).to eq("fedora")
@@ -493,7 +493,7 @@ describe Ohai::System, "Linux plugin platform" do
       end
 
       it "sets platform to bigip" do
-        expect(File).to receive(:read).with("/etc/f5-release").and_return("BIG-IP release 13.0.0 (Final)")
+        expect(plugin).to receive(:file_read).with("/etc/f5-release").and_return("BIG-IP release 13.0.0 (Final)")
         plugin.run
         expect(plugin[:platform]).to eq("bigip")
         expect(plugin[:platform_family]).to eq("rhel")
@@ -553,20 +553,20 @@ describe Ohai::System, "Linux plugin platform" do
         end
 
         it "reads the platform as centos and version as 7.5" do
-          expect(File).to receive(:read).with("/etc/redhat-release").and_return("CentOS Linux release 7.5.1804 (Core)")
+          expect(plugin).to receive(:file_read).with("/etc/redhat-release").and_return("CentOS Linux release 7.5.1804 (Core)")
           plugin.run
           expect(plugin[:platform]).to eq("centos")
           expect(plugin[:platform_version]).to eq("7.5.1804")
         end
 
         it "reads platform of Red Hat with a space" do
-          expect(File).to receive(:read).with("/etc/redhat-release").and_return("Red Hat Enterprise Linux Server release 6.5 (Santiago)")
+          expect(plugin).to receive(:file_read).with("/etc/redhat-release").and_return("Red Hat Enterprise Linux Server release 6.5 (Santiago)")
           plugin.run
           expect(plugin[:platform]).to eq("redhat")
         end
 
         it "reads the platform as redhat without a space" do
-          expect(File).to receive(:read).with("/etc/redhat-release").and_return("RedHat release 5.3")
+          expect(plugin).to receive(:file_read).with("/etc/redhat-release").and_return("RedHat release 5.3")
           plugin.run
           expect(plugin[:platform]).to eq("redhat")
           expect(plugin[:platform_version]).to eq("5.3")
@@ -585,8 +585,8 @@ describe Ohai::System, "Linux plugin platform" do
         it "reads the platform as parallels and version as 6.0.5" do
           plugin[:lsb][:id] = "CloudLinuxServer"
           plugin[:lsb][:release] = "6.5"
-          allow(File).to receive(:read).with("/etc/redhat-release").and_return("CloudLinux Server release 6.5 (Pavel Popovich)")
-          expect(File).to receive(:read).with("/etc/parallels-release").and_return("Parallels Cloud Server 6.0.5 (20007)")
+          allow(plugin).to receive(:file_read).with("/etc/redhat-release").and_return("CloudLinux Server release 6.5 (Pavel Popovich)")
+          expect(plugin).to receive(:file_read).with("/etc/parallels-release").and_return("Parallels Cloud Server 6.0.5 (20007)")
           plugin.run
           expect(plugin[:platform]).to eq("parallels")
           expect(plugin[:platform_version]).to eq("6.0.5")
@@ -601,8 +601,8 @@ describe Ohai::System, "Linux plugin platform" do
         end
 
         it "reads the platform as parallels and version as 6.0.5" do
-          allow(File).to receive(:read).with("/etc/redhat-release").and_return("CloudLinux Server release 6.5 (Pavel Popovich)")
-          expect(File).to receive(:read).with("/etc/parallels-release").and_return("Parallels Cloud Server 6.0.5 (20007)")
+          allow(plugin).to receive(:file_read).with("/etc/redhat-release").and_return("CloudLinux Server release 6.5 (Pavel Popovich)")
+          expect(plugin).to receive(:file_read).with("/etc/parallels-release").and_return("Parallels Cloud Server 6.0.5 (20007)")
           plugin.run
           expect(plugin[:platform]).to eq("parallels")
           expect(plugin[:platform_version]).to eq("6.0.5")
@@ -624,8 +624,8 @@ describe Ohai::System, "Linux plugin platform" do
           it "reads the platform as oracle and version as 5.7" do
             plugin[:lsb][:id] = "EnterpriseEnterpriseServer"
             plugin[:lsb][:release] = "5.7"
-            allow(File).to receive(:read).with("/etc/redhat-release").and_return("Red Hat Enterprise Linux Server release 5.7 (Tikanga)")
-            expect(File).to receive(:read).with("/etc/enterprise-release").and_return("Enterprise Linux Enterprise Linux Server release 5.7 (Carthage)")
+            allow(plugin).to receive(:file_read).with("/etc/redhat-release").and_return("Red Hat Enterprise Linux Server release 5.7 (Tikanga)")
+            expect(plugin).to receive(:file_read).with("/etc/enterprise-release").and_return("Enterprise Linux Enterprise Linux Server release 5.7 (Carthage)")
             plugin.run
             expect(plugin[:platform]).to eq("oracle")
             expect(plugin[:platform_version]).to eq("5.7")
@@ -639,8 +639,8 @@ describe Ohai::System, "Linux plugin platform" do
           it "reads the platform as oracle and version as 6.1" do
             plugin[:lsb][:id] = "OracleServer"
             plugin[:lsb][:release] = "6.1"
-            allow(File).to receive(:read).with("/etc/redhat-release").and_return("Red Hat Enterprise Linux Server release 6.1 (Santiago)")
-            expect(File).to receive(:read).with("/etc/oracle-release").and_return("Oracle Linux Server release 6.1")
+            allow(plugin).to receive(:file_read).with("/etc/redhat-release").and_return("Red Hat Enterprise Linux Server release 6.1 (Santiago)")
+            expect(plugin).to receive(:file_read).with("/etc/oracle-release").and_return("Oracle Linux Server release 6.1")
             plugin.run
             expect(plugin[:platform]).to eq("oracle")
             expect(plugin[:platform_version]).to eq("6.1")
@@ -659,24 +659,24 @@ describe Ohai::System, "Linux plugin platform" do
           let(:have_enterprise_release) { true }
 
           it "reads the platform as oracle and version as 5" do
-            allow(File).to receive(:read).with("/etc/redhat-release").and_return("Enterprise Linux Enterprise Linux Server release 5 (Carthage)")
-            expect(File).to receive(:read).with("/etc/enterprise-release").and_return("Enterprise Linux Enterprise Linux Server release 5 (Carthage)")
+            allow(plugin).to receive(:file_read).with("/etc/redhat-release").and_return("Enterprise Linux Enterprise Linux Server release 5 (Carthage)")
+            expect(plugin).to receive(:file_read).with("/etc/enterprise-release").and_return("Enterprise Linux Enterprise Linux Server release 5 (Carthage)")
             plugin.run
             expect(plugin[:platform]).to eq("oracle")
             expect(plugin[:platform_version]).to eq("5")
           end
 
           it "reads the platform as oracle and version as 5.1" do
-            allow(File).to receive(:read).with("/etc/redhat-release").and_return("Enterprise Linux Enterprise Linux Server release 5.1 (Carthage)")
-            expect(File).to receive(:read).with("/etc/enterprise-release").and_return("Enterprise Linux Enterprise Linux Server release 5.1 (Carthage)")
+            allow(plugin).to receive(:file_read).with("/etc/redhat-release").and_return("Enterprise Linux Enterprise Linux Server release 5.1 (Carthage)")
+            expect(plugin).to receive(:file_read).with("/etc/enterprise-release").and_return("Enterprise Linux Enterprise Linux Server release 5.1 (Carthage)")
             plugin.run
             expect(plugin[:platform]).to eq("oracle")
             expect(plugin[:platform_version]).to eq("5.1")
           end
 
           it "reads the platform as oracle and version as 5.7" do
-            allow(File).to receive(:read).with("/etc/redhat-release").and_return("Red Hat Enterprise Linux Server release 5.7 (Tikanga)")
-            expect(File).to receive(:read).with("/etc/enterprise-release").and_return("Enterprise Linux Enterprise Linux Server release 5.7 (Carthage)")
+            allow(plugin).to receive(:file_read).with("/etc/redhat-release").and_return("Red Hat Enterprise Linux Server release 5.7 (Tikanga)")
+            expect(plugin).to receive(:file_read).with("/etc/enterprise-release").and_return("Enterprise Linux Enterprise Linux Server release 5.7 (Carthage)")
             plugin.run
             expect(plugin[:platform]).to eq("oracle")
             expect(plugin[:platform_version]).to eq("5.7")
@@ -689,16 +689,16 @@ describe Ohai::System, "Linux plugin platform" do
           let(:have_oracle_release) { true }
 
           it "reads the platform as oracle and version as 6.0" do
-            allow(File).to receive(:read).with("/etc/redhat-release").and_return("Red Hat Enterprise Linux Server release 6.0 (Santiago)")
-            expect(File).to receive(:read).with("/etc/oracle-release").and_return("Oracle Linux Server release 6.0")
+            allow(plugin).to receive(:file_read).with("/etc/redhat-release").and_return("Red Hat Enterprise Linux Server release 6.0 (Santiago)")
+            expect(plugin).to receive(:file_read).with("/etc/oracle-release").and_return("Oracle Linux Server release 6.0")
             plugin.run
             expect(plugin[:platform]).to eq("oracle")
             expect(plugin[:platform_version]).to eq("6.0")
           end
 
           it "reads the platform as oracle and version as 6.1" do
-            allow(File).to receive(:read).with("/etc/redhat-release").and_return("Red Hat Enterprise Linux Server release 6.1 (Santiago)")
-            expect(File).to receive(:read).with("/etc/oracle-release").and_return("Oracle Linux Server release 6.1")
+            allow(plugin).to receive(:file_read).with("/etc/redhat-release").and_return("Red Hat Enterprise Linux Server release 6.1 (Santiago)")
+            expect(plugin).to receive(:file_read).with("/etc/oracle-release").and_return("Oracle Linux Server release 6.1")
             plugin.run
             expect(plugin[:platform]).to eq("oracle")
             expect(plugin[:platform_version]).to eq("6.1")
@@ -719,7 +719,7 @@ describe Ohai::System, "Linux plugin platform" do
 
           it "reads the platform as opensuse on openSUSE" do
             plugin[:lsb][:release] = "12.1"
-            expect(File).to receive(:read).with("/etc/SuSE-release").and_return("openSUSE 12.1 (x86_64)\nVERSION = 12.1\nCODENAME = Asparagus\n")
+            expect(plugin).to receive(:file_read).with("/etc/SuSE-release").and_return("openSUSE 12.1 (x86_64)\nVERSION = 12.1\nCODENAME = Asparagus\n")
             plugin.run
             expect(plugin[:platform]).to eq("opensuse")
             expect(plugin[:platform_family]).to eq("suse")
@@ -736,14 +736,14 @@ describe Ohai::System, "Linux plugin platform" do
           end
 
           it "sets platform and platform_family to suse and bogus verion to 10.0" do
-            expect(File).to receive(:read).with("/etc/SuSE-release").at_least(:once).and_return("VERSION = 10.0")
+            expect(plugin).to receive(:file_read).with("/etc/SuSE-release").at_least(:once).and_return("VERSION = 10.0")
             plugin.run
             expect(plugin[:platform]).to eq("suse")
             expect(plugin[:platform_family]).to eq("suse")
           end
 
           it "reads the version as 11.2" do
-            expect(File).to receive(:read).with("/etc/SuSE-release").and_return("SUSE Linux Enterprise Server 11.2 (i586)\nVERSION = 11\nPATCHLEVEL = 2\n")
+            expect(plugin).to receive(:file_read).with("/etc/SuSE-release").and_return("SUSE Linux Enterprise Server 11.2 (i586)\nVERSION = 11\nPATCHLEVEL = 2\n")
             plugin.run
             expect(plugin[:platform]).to eq("suse")
             expect(plugin[:platform_version]).to eq("11.2")
@@ -751,7 +751,7 @@ describe Ohai::System, "Linux plugin platform" do
           end
 
           it "[OHAI-272] should read the version as 11.3" do
-            expect(File).to receive(:read).with("/etc/SuSE-release").once.and_return("openSUSE 11.3 (x86_64)\nVERSION = 11.3")
+            expect(plugin).to receive(:file_read).with("/etc/SuSE-release").once.and_return("openSUSE 11.3 (x86_64)\nVERSION = 11.3")
             plugin.run
             expect(plugin[:platform]).to eq("opensuse")
             expect(plugin[:platform_version]).to eq("11.3")
@@ -759,7 +759,7 @@ describe Ohai::System, "Linux plugin platform" do
           end
 
           it "[OHAI-272] should read the version as 11.4" do
-            expect(File).to receive(:read).with("/etc/SuSE-release").once.and_return("openSUSE 11.4 (i586)\nVERSION = 11.4\nCODENAME = Celadon")
+            expect(plugin).to receive(:file_read).with("/etc/SuSE-release").once.and_return("openSUSE 11.4 (i586)\nVERSION = 11.4\nCODENAME = Celadon")
             plugin.run
             expect(plugin[:platform]).to eq("opensuse")
             expect(plugin[:platform_version]).to eq("11.4")
@@ -767,14 +767,14 @@ describe Ohai::System, "Linux plugin platform" do
           end
 
           it "reads the platform as opensuse on openSUSE" do
-            expect(File).to receive(:read).with("/etc/SuSE-release").and_return("openSUSE 12.2 (x86_64)\nVERSION = 12.2\nCODENAME = Mantis\n")
+            expect(plugin).to receive(:file_read).with("/etc/SuSE-release").and_return("openSUSE 12.2 (x86_64)\nVERSION = 12.2\nCODENAME = Mantis\n")
             plugin.run
             expect(plugin[:platform]).to eq("opensuse")
             expect(plugin[:platform_family]).to eq("suse")
           end
 
           it "reads the platform as opensuseleap on openSUSE Leap" do
-            expect(File).to receive(:read).with("/etc/SuSE-release").and_return("openSUSE 42.1 (x86_64)\nVERSION = 42.1\nCODENAME = Malachite\n")
+            expect(plugin).to receive(:file_read).with("/etc/SuSE-release").and_return("openSUSE 42.1 (x86_64)\nVERSION = 42.1\nCODENAME = Malachite\n")
             plugin.run
             expect(plugin[:platform]).to eq("opensuseleap")
             expect(plugin[:platform_family]).to eq("suse")
@@ -797,7 +797,7 @@ describe Ohai::System, "Linux plugin platform" do
       end
 
       before do
-        expect(File).to receive(:read).with("/usr/lib/os-release").and_return(usr_lib_os_release_content)
+        expect(plugin).to receive(:file_read).with("/usr/lib/os-release").and_return(usr_lib_os_release_content)
       end
 
       it "sets platform to clearlinux and platform_family to clearlinux" do
diff --git a/spec/unit/plugins/linux/virtualization_spec.rb b/spec/unit/plugins/linux/virtualization_spec.rb
index 3234a09b..eeb12176 100644
--- a/spec/unit/plugins/linux/virtualization_spec.rb
+++ b/spec/unit/plugins/linux/virtualization_spec.rb
@@ -24,23 +24,23 @@ describe Ohai::System, "Linux virtualization platform" do
   before do
     allow(plugin).to receive(:collect_os).and_return(:linux)
 
-    # default to all requested Files not existing
-    allow(File).to receive(:exist?).with("/proc/xen").and_return(false)
-    allow(File).to receive(:exist?).with("/proc/xen/capabilities").and_return(false)
-    allow(File).to receive(:exist?).with("/proc/modules").and_return(false)
-    allow(File).to receive(:exist?).with("/proc/cpuinfo").and_return(false)
-    allow(File).to receive(:exist?).with("/var/lib/hyperv/.kvp_pool_3").and_return(false)
-    allow(File).to receive(:exist?).with("/proc/self/status").and_return(false)
-    allow(File).to receive(:exist?).with("/proc/bc/0").and_return(false)
-    allow(File).to receive(:exist?).with("/proc/vz").and_return(false)
-    allow(File).to receive(:exist?).with("/proc/self/cgroup").and_return(false)
-    allow(File).to receive(:exist?).with("/.dockerenv").and_return(false)
-    allow(File).to receive(:exist?).with("/.dockerinit").and_return(false)
-    allow(File).to receive(:exist?).with("/sys/devices/virtual/misc/kvm").and_return(false)
-    allow(File).to receive(:exist?).with("/dev/lxd/sock").and_return(false)
-    allow(File).to receive(:exist?).with("/var/lib/lxd/devlxd").and_return(false)
-    allow(File).to receive(:exist?).with("/var/snap/lxd/common/lxd/devlxd").and_return(false)
-    allow(File).to receive(:exist?).with("/proc/1/environ").and_return(false)
+    # default to all requested plugins not existing
+    allow(plugin).to receive(:file_exist?).with("/proc/xen").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/proc/xen/capabilities").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/proc/modules").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/proc/cpuinfo").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/var/lib/hyperv/.kvp_pool_3").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/proc/self/status").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/proc/bc/0").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/proc/vz").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/proc/self/cgroup").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/.dockerenv").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/.dockerinit").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/sys/devices/virtual/misc/kvm").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/dev/lxd/sock").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/var/lib/lxd/devlxd").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/var/snap/lxd/common/lxd/devlxd").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/proc/1/environ").and_return(false)
 
     # default the which wrappers to nil
     allow(plugin).to receive(:which).with("lxc-version").and_return(nil)
@@ -51,8 +51,8 @@ describe Ohai::System, "Linux virtualization platform" do
 
   describe "when we are checking for xen" do
     it "sets xen guest if /proc/xen exists but /proc/xen/capabilities does not" do
-      expect(File).to receive(:exist?).with("/proc/xen").and_return(true)
-      expect(File).to receive(:exist?).with("/proc/xen/capabilities").and_return(false)
+      expect(plugin).to receive(:file_exist?).with("/proc/xen").and_return(true)
+      expect(plugin).to receive(:file_exist?).with("/proc/xen/capabilities").and_return(false)
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("xen")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -60,9 +60,9 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "sets xen host if /proc/xen/capabilities contains control_d " do
-      expect(File).to receive(:exist?).with("/proc/xen").and_return(true)
-      expect(File).to receive(:exist?).with("/proc/xen/capabilities").and_return(true)
-      allow(File).to receive(:read).with("/proc/xen/capabilities").and_return("control_d")
+      expect(plugin).to receive(:file_exist?).with("/proc/xen").and_return(true)
+      expect(plugin).to receive(:file_exist?).with("/proc/xen/capabilities").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/xen/capabilities").and_return("control_d")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("xen")
       expect(plugin[:virtualization][:role]).to eq("host")
@@ -70,9 +70,9 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "sets xen guest if /proc/xen/capabilities exists but is empty" do
-      expect(File).to receive(:exist?).with("/proc/xen").and_return(true)
-      expect(File).to receive(:exist?).with("/proc/xen/capabilities").and_return(true)
-      allow(File).to receive(:read).with("/proc/xen/capabilities").and_return("")
+      expect(plugin).to receive(:file_exist?).with("/proc/xen").and_return(true)
+      expect(plugin).to receive(:file_exist?).with("/proc/xen/capabilities").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/xen/capabilities").and_return("")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("xen")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -80,7 +80,7 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "does not set virtualization if xen isn't there" do
-      expect(File).to receive(:exist?).at_least(:once).and_return(false)
+      expect(plugin).to receive(:file_exist?).at_least(:once).and_return(false)
       plugin.run
       expect(plugin[:virtualization]).to eq({ "systems" => {} })
     end
@@ -108,8 +108,8 @@ describe Ohai::System, "Linux virtualization platform" do
 
   describe "when we are checking for kvm" do
     it "sets kvm guest if /sys/devices/virtual/misc/kvm exists & hypervisor cpu feature is present" do
-      allow(File).to receive(:exist?).with("/sys/devices/virtual/misc/kvm").and_return(true)
-      allow(File).to receive(:read).with("/proc/cpuinfo").and_return("fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx rdtscp lm constant_tsc arch_perfmon rep_good nopl pni vmx ssse3 cx16 sse4_1 sse4_2 x2apic popcnt hypervisor lahf_lm vnmi ept tsc_adjust")
+      allow(plugin).to receive(:file_exist?).with("/sys/devices/virtual/misc/kvm").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/cpuinfo").and_return("fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx rdtscp lm constant_tsc arch_perfmon rep_good nopl pni vmx ssse3 cx16 sse4_1 sse4_2 x2apic popcnt hypervisor lahf_lm vnmi ept tsc_adjust")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("kvm")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -117,8 +117,8 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "sets kvm host if /sys/devices/virtual/misc/kvm exists & hypervisor cpu feature is not present" do
-      allow(File).to receive(:exist?).with("/sys/devices/virtual/misc/kvm").and_return(true)
-      allow(File).to receive(:read).with("/proc/cpuinfo").and_return("fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida dtherm tpr_shadow vnmi flexpriority ept vpid")
+      allow(plugin).to receive(:file_exist?).with("/sys/devices/virtual/misc/kvm").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/cpuinfo").and_return("fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida dtherm tpr_shadow vnmi flexpriority ept vpid")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("kvm")
       expect(plugin[:virtualization][:role]).to eq("host")
@@ -126,8 +126,8 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "sets kvm guest if /proc/cpuinfo contains QEMU Virtual CPU" do
-      expect(File).to receive(:exist?).with("/proc/cpuinfo").and_return(true)
-      allow(File).to receive(:read).with("/proc/cpuinfo").and_return("QEMU Virtual CPU")
+      expect(plugin).to receive(:file_exist?).with("/proc/cpuinfo").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/cpuinfo").and_return("QEMU Virtual CPU")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("kvm")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -135,8 +135,8 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "sets kvm guest if /proc/cpuinfo contains Common KVM processor" do
-      expect(File).to receive(:exist?).with("/proc/cpuinfo").and_return(true)
-      allow(File).to receive(:read).with("/proc/cpuinfo").and_return("Common KVM processor")
+      expect(plugin).to receive(:file_exist?).with("/proc/cpuinfo").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/cpuinfo").and_return("Common KVM processor")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("kvm")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -144,8 +144,8 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "sets kvm guest if /proc/cpuinfo contains Common 32-bit KVM processor" do
-      expect(File).to receive(:exist?).with("/proc/cpuinfo").and_return(true)
-      allow(File).to receive(:read).with("/proc/cpuinfo").and_return("Common 32-bit KVM processor")
+      expect(plugin).to receive(:file_exist?).with("/proc/cpuinfo").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/cpuinfo").and_return("Common 32-bit KVM processor")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("kvm")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -153,7 +153,7 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "does not set virtualization if kvm isn't there" do
-      expect(File).to receive(:exist?).at_least(:once).and_return(false)
+      expect(plugin).to receive(:file_exist?).at_least(:once).and_return(false)
       plugin.run
       expect(plugin[:virtualization]).to eq({ "systems" => {} })
     end
@@ -161,8 +161,8 @@ describe Ohai::System, "Linux virtualization platform" do
 
   describe "when we are checking for VirtualBox" do
     it "sets vbox host if /proc/modules contains vboxdrv" do
-      expect(File).to receive(:exist?).with("/proc/modules").and_return(true)
-      allow(File).to receive(:read).with("/proc/modules").and_return("vboxdrv 268268 3 vboxnetadp,vboxnetflt")
+      expect(plugin).to receive(:file_exist?).with("/proc/modules").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/modules").and_return("vboxdrv 268268 3 vboxnetadp,vboxnetflt")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("vbox")
       expect(plugin[:virtualization][:role]).to eq("host")
@@ -170,8 +170,8 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "sets vbox gues if /proc/modules contains vboxguest" do
-      expect(File).to receive(:exist?).with("/proc/modules").and_return(true)
-      allow(File).to receive(:read).with("/proc/modules").and_return("vboxguest 214901 2 vboxsf, Live 0xffffffffa00db000 (OF)")
+      expect(plugin).to receive(:file_exist?).with("/proc/modules").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/modules").and_return("vboxguest 214901 2 vboxsf, Live 0xffffffffa00db000 (OF)")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("vbox")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -179,7 +179,7 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "does not set virtualization if vbox isn't there" do
-      expect(File).to receive(:exist?).at_least(:once).and_return(false)
+      expect(plugin).to receive(:file_exist?).at_least(:once).and_return(false)
       plugin.run
       expect(plugin[:virtualization]).to eq({ "systems" => {} })
     end
@@ -214,8 +214,8 @@ describe Ohai::System, "Linux virtualization platform" do
 
   describe "when we are checking for Hyper-V guest and the hostname of the host" do
     it "sets Hyper-V guest if /var/lib/hyperv/.kvp_pool_3 contains hyper_v.example.com" do
-      expect(File).to receive(:exist?).with("/var/lib/hyperv/.kvp_pool_3").and_return(true)
-      allow(File).to receive(:read).with("/var/lib/hyperv/.kvp_pool_3").and_return("HostNamehyper_v.example.comHostingSystemEditionId")
+      expect(plugin).to receive(:file_exist?).with("/var/lib/hyperv/.kvp_pool_3").and_return(true)
+      allow(plugin).to receive(:file_read).with("/var/lib/hyperv/.kvp_pool_3").and_return("HostNamehyper_v.example.comHostingSystemEditionId")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("hyperv")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -226,8 +226,8 @@ describe Ohai::System, "Linux virtualization platform" do
 
   describe "when we are checking for Linux-VServer" do
     it "sets Linux-VServer host if /proc/self/status contains s_context: 0" do
-      expect(File).to receive(:exist?).with("/proc/self/status").and_return(true)
-      allow(File).to receive(:read).with("/proc/self/status").and_return("s_context: 0")
+      expect(plugin).to receive(:file_exist?).with("/proc/self/status").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/self/status").and_return("s_context: 0")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("linux-vserver")
       expect(plugin[:virtualization][:role]).to eq("host")
@@ -235,8 +235,8 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "sets Linux-VServer host if /proc/self/status contains VxID: 0" do
-      expect(File).to receive(:exist?).with("/proc/self/status").and_return(true)
-      allow(File).to receive(:read).with("/proc/self/status").and_return("VxID: 0")
+      expect(plugin).to receive(:file_exist?).with("/proc/self/status").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/self/status").and_return("VxID: 0")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("linux-vserver")
       expect(plugin[:virtualization][:role]).to eq("host")
@@ -244,8 +244,8 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "sets Linux-VServer host if /proc/self/status contains multiple space VxID:   0" do
-      expect(File).to receive(:exist?).with("/proc/self/status").and_return(true)
-      allow(File).to receive(:read).with("/proc/self/status").and_return("VxID:   0")
+      expect(plugin).to receive(:file_exist?).with("/proc/self/status").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/self/status").and_return("VxID:   0")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("linux-vserver")
       expect(plugin[:virtualization][:role]).to eq("host")
@@ -253,8 +253,8 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "sets Linux-VServer host if /proc/self/status contains tabbed VxID:\t0" do
-      expect(File).to receive(:exist?).with("/proc/self/status").and_return(true)
-      allow(File).to receive(:read).with("/proc/self/status").and_return("VxID:\t0")
+      expect(plugin).to receive(:file_exist?).with("/proc/self/status").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/self/status").and_return("VxID:\t0")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("linux-vserver")
       expect(plugin[:virtualization][:role]).to eq("host")
@@ -262,8 +262,8 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "sets Linux-VServer guest if /proc/self/status contains s_context > 0" do
-      expect(File).to receive(:exist?).with("/proc/self/status").and_return(true)
-      allow(File).to receive(:read).with("/proc/self/status").and_return("s_context: 2")
+      expect(plugin).to receive(:file_exist?).with("/proc/self/status").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/self/status").and_return("s_context: 2")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("linux-vserver")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -271,8 +271,8 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "sets Linux-VServer guest if /proc/self/status contains VxID > 0" do
-      expect(File).to receive(:exist?).with("/proc/self/status").and_return(true)
-      allow(File).to receive(:read).with("/proc/self/status").and_return("VxID: 2")
+      expect(plugin).to receive(:file_exist?).with("/proc/self/status").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/self/status").and_return("VxID: 2")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("linux-vserver")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -280,7 +280,7 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "does not set virtualization if Linux-VServer isn't there" do
-      expect(File).to receive(:exist?).at_least(:once).and_return(false)
+      expect(plugin).to receive(:file_exist?).at_least(:once).and_return(false)
       plugin.run
       expect(plugin[:virtualization]).to eq({ "systems" => {} })
     end
@@ -288,7 +288,7 @@ describe Ohai::System, "Linux virtualization platform" do
 
   describe "when we are checking for openvz" do
     it "sets openvz host if /proc/bc/0 exists" do
-      expect(File).to receive(:exist?).with("/proc/bc/0").and_return(true)
+      expect(plugin).to receive(:file_exist?).with("/proc/bc/0").and_return(true)
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("openvz")
       expect(plugin[:virtualization][:role]).to eq("host")
@@ -296,8 +296,8 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "sets openvz guest if /proc/bc/0 does not exist and /proc/vz exists" do
-      expect(File).to receive(:exist?).with("/proc/bc/0").and_return(false)
-      expect(File).to receive(:exist?).with("/proc/vz").and_return(true)
+      expect(plugin).to receive(:file_exist?).with("/proc/bc/0").and_return(false)
+      expect(plugin).to receive(:file_exist?).with("/proc/vz").and_return(true)
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("openvz")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -305,8 +305,8 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "does not set virtualization if openvz isn't there" do
-      expect(File).to receive(:exist?).with("/proc/bc/0").and_return(false)
-      expect(File).to receive(:exist?).with("/proc/vz").and_return(false)
+      expect(plugin).to receive(:file_exist?).with("/proc/bc/0").and_return(false)
+      expect(plugin).to receive(:file_exist?).with("/proc/vz").and_return(false)
       plugin.run
       expect(plugin[:virtualization]).to eq({ "systems" => {} })
     end
@@ -314,7 +314,7 @@ describe Ohai::System, "Linux virtualization platform" do
 
   describe "when we are checking for lxd" do
     it "sets lxc guest if /dev/lxd/sock exists" do
-      expect(File).to receive(:exist?).with("/dev/lxd/sock").and_return(true)
+      expect(plugin).to receive(:file_exist?).with("/dev/lxd/sock").and_return(true)
 
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("lxd")
@@ -322,7 +322,7 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "sets lxd host if /var/lib/lxd/devlxd exists" do
-      expect(File).to receive(:exist?).with("/var/lib/lxd/devlxd").and_return(true)
+      expect(plugin).to receive(:file_exist?).with("/var/lib/lxd/devlxd").and_return(true)
 
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("lxd")
@@ -330,7 +330,7 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "sets lxd host if /var/snap/lxd/common/lxd/devlxd exists" do
-      expect(File).to receive(:exist?).with("/var/snap/lxd/common/lxd/devlxd").and_return(true)
+      expect(plugin).to receive(:file_exist?).with("/var/snap/lxd/common/lxd/devlxd").and_return(true)
 
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("lxd")
@@ -350,8 +350,8 @@ describe Ohai::System, "Linux virtualization platform" do
         2:cpu:/lxc/baa660ed81bc81d262ac6e19486142aeec5fce2043e2a173eb2505c6fbed89bc
         1:cpuset:/
       CGROUP
-      expect(File).to receive(:exist?).with("/proc/self/cgroup").and_return(true)
-      allow(File).to receive(:read).with("/proc/self/cgroup").and_return(self_cgroup)
+      expect(plugin).to receive(:file_exist?).with("/proc/self/cgroup").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/self/cgroup").and_return(self_cgroup)
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("lxc")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -369,8 +369,8 @@ describe Ohai::System, "Linux virtualization platform" do
         2:cpu:/lxc/vanilla
         1:cpuset:/lxc/vanilla
       CGROUP
-      expect(File).to receive(:exist?).with("/proc/self/cgroup").and_return(true)
-      allow(File).to receive(:read).with("/proc/self/cgroup").and_return(self_cgroup)
+      expect(plugin).to receive(:file_exist?).with("/proc/self/cgroup").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/self/cgroup").and_return(self_cgroup)
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("lxc")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -388,9 +388,9 @@ describe Ohai::System, "Linux virtualization platform" do
         2:cpu:/Charlie
         1:cpuset:/Charlie
       CGROUP
-      allow(File).to receive(:read).with("/proc/1/environ").and_return("")
-      expect(File).to receive(:exist?).with("/proc/self/cgroup").and_return(true)
-      allow(File).to receive(:read).with("/proc/self/cgroup").and_return(self_cgroup)
+      allow(plugin).to receive(:file_read).with("/proc/1/environ").and_return("")
+      expect(plugin).to receive(:file_exist?).with("/proc/self/cgroup").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/self/cgroup").and_return(self_cgroup)
       plugin.run
       expect(plugin[:virtualization]).to eq({ "systems" => {} })
     end
@@ -407,9 +407,9 @@ describe Ohai::System, "Linux virtualization platform" do
           2:cpu:/
           1:cpuset:/
         CGROUP
-        expect(File).to receive(:exist?).with("/proc/self/cgroup").and_return(true)
-        allow(File).to receive(:read).with("/proc/self/cgroup").and_return(self_cgroup)
-        allow(File).to receive(:read).with("/proc/1/environ").and_return("")
+        expect(plugin).to receive(:file_exist?).with("/proc/self/cgroup").and_return(true)
+        allow(plugin).to receive(:file_read).with("/proc/self/cgroup").and_return(self_cgroup)
+        allow(plugin).to receive(:file_read).with("/proc/1/environ").and_return("")
       end
 
       it "sets lxc host if lxc-version exists" do
@@ -447,7 +447,7 @@ describe Ohai::System, "Linux virtualization platform" do
 
       it "sets lxc guest if /proc/1/environ has lxccontainer string in it" do
         one_environ = "container=lxccontainer_ttys=/dev/pts/0 /dev/pts/1 /dev/pts/2 /dev/pts/3".chomp
-        allow(File).to receive(:read).with("/proc/1/environ").and_return(one_environ)
+        allow(plugin).to receive(:file_read).with("/proc/1/environ").and_return(one_environ)
         plugin.run
         expect(plugin[:virtualization][:system]).to eq("lxc")
         expect(plugin[:virtualization][:role]).to eq("guest")
@@ -456,7 +456,7 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "does not set virtualization if /proc/self/cgroup isn't there" do
-      expect(File).to receive(:exist?).with("/proc/self/cgroup").and_return(false)
+      expect(plugin).to receive(:file_exist?).with("/proc/self/cgroup").and_return(false)
       plugin.run
       expect(plugin[:virtualization]).to eq({ "systems" => {} })
     end
@@ -464,10 +464,10 @@ describe Ohai::System, "Linux virtualization platform" do
 
   describe "when we are checking for systemd-nspawn" do
     it "sets nspawn guest if /proc/1/environ has nspawn string in it" do
-      allow(File).to receive(:exist?).with("/proc/self/cgroup").and_return(true)
+      allow(plugin).to receive(:file_exist?).with("/proc/self/cgroup").and_return(true)
       one_environ = "container=systemd-nspawn_ttys=/dev/pts/0 /dev/pts/1 /dev/pts/2 /dev/pts/3".chomp
-      allow(File).to receive(:read).with("/proc/1/environ").and_return(one_environ)
-      allow(File).to receive(:read).with("/proc/self/cgroup").and_return("")
+      allow(plugin).to receive(:file_read).with("/proc/1/environ").and_return(one_environ)
+      allow(plugin).to receive(:file_read).with("/proc/self/cgroup").and_return("")
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("nspawn")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -486,8 +486,8 @@ describe Ohai::System, "Linux virtualization platform" do
         2:cpu:/docker/baa660ed81bc81d262ac6e19486142aeec5fce2043e2a173eb2505c6fbed89bc
         1:cpuset:/
       CGROUP
-      allow(File).to receive(:exist?).with("/proc/self/cgroup").and_return(true)
-      allow(File).to receive(:read).with("/proc/self/cgroup").and_return(self_cgroup)
+      allow(plugin).to receive(:file_exist?).with("/proc/self/cgroup").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/self/cgroup").and_return(self_cgroup)
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("docker")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -505,8 +505,8 @@ describe Ohai::System, "Linux virtualization platform" do
         2:cpu:/docker/vanilla
         1:cpuset:/docker/vanilla
       CGROUP
-      allow(File).to receive(:exist?).with("/proc/self/cgroup").and_return(true)
-      allow(File).to receive(:read).with("/proc/self/cgroup").and_return(self_cgroup)
+      allow(plugin).to receive(:file_exist?).with("/proc/self/cgroup").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/self/cgroup").and_return(self_cgroup)
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("docker")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -529,8 +529,8 @@ describe Ohai::System, "Linux virtualization platform" do
         2:cpu:/docker-ce/docker/b15b85d19304436488a78d06afeb108d94b20bb6898d852b65cad51bd7dc9468
         1:cpuset:/docker-ce/docker/b15b85d19304436488a78d06afeb108d94b20bb6898d852b65cad51bd7dc9468
       CGROUP
-      allow(File).to receive(:exist?).with("/proc/self/cgroup").and_return(true)
-      allow(File).to receive(:read).with("/proc/self/cgroup").and_return(self_cgroup)
+      allow(plugin).to receive(:file_exist?).with("/proc/self/cgroup").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/self/cgroup").and_return(self_cgroup)
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("docker")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -550,8 +550,8 @@ describe Ohai::System, "Linux virtualization platform" do
         2:cpu,cpuacct:/system.slice/docker-47341c91be8d491cb3b8a475ad5b4aef6e79bf728cbb351c384e4a6c410f172f.scope
         1:name=systemd:/system.slice/docker-47341c91be8d491cb3b8a475ad5b4aef6e79bf728cbb351c384e4a6c410f172f.scope
       CGROUP
-      allow(File).to receive(:exist?).with("/proc/self/cgroup").and_return(true)
-      allow(File).to receive(:read).with("/proc/self/cgroup").and_return(self_cgroup)
+      allow(plugin).to receive(:file_exist?).with("/proc/self/cgroup").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/self/cgroup").and_return(self_cgroup)
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("docker")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -569,9 +569,9 @@ describe Ohai::System, "Linux virtualization platform" do
         2:cpu:/Charlie
         1:cpuset:/Charlie
       CGROUP
-      allow(File).to receive(:exist?).with("/proc/self/cgroup").and_return(true)
-      allow(File).to receive(:read).with("/proc/self/cgroup").and_return(self_cgroup)
-      allow(File).to receive(:read).with("/proc/1/environ").and_return("")
+      allow(plugin).to receive(:file_exist?).with("/proc/self/cgroup").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/self/cgroup").and_return(self_cgroup)
+      allow(plugin).to receive(:file_read).with("/proc/1/environ").and_return("")
       plugin.run
       expect(plugin[:virtualization]).to eq({ "systems" => {} })
     end
@@ -588,8 +588,8 @@ describe Ohai::System, "Linux virtualization platform" do
           2:cpu:/
           1:cpuset:/
         CGROUP
-        allow(File).to receive(:exist?).with("/proc/self/cgroup").and_return(true)
-        allow(File).to receive(:read).with("/proc/self/cgroup").and_return(self_cgroup)
+        allow(plugin).to receive(:file_exist?).with("/proc/self/cgroup").and_return(true)
+        allow(plugin).to receive(:file_read).with("/proc/self/cgroup").and_return(self_cgroup)
         plugin.run
         expect(plugin[:virtualization]).to eq({ "systems" => {} })
       end
@@ -613,13 +613,13 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "does not set virtualization if /proc/self/cgroup isn't there" do
-      allow(File).to receive(:exist?).with("/proc/self/cgroup").and_return(false)
+      allow(plugin).to receive(:file_exist?).with("/proc/self/cgroup").and_return(false)
       plugin.run
       expect(plugin[:virtualization]).to eq({ "systems" => {} })
     end
 
     it "sets virtualization if /.dockerenv exists" do
-      allow(File).to receive(:exist?).with("/.dockerenv").and_return(true)
+      allow(plugin).to receive(:file_exist?).with("/.dockerenv").and_return(true)
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("docker")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -627,7 +627,7 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "sets virtualization if /.dockerinit exists" do
-      allow(File).to receive(:exist?).with("/.dockerinit").and_return(true)
+      allow(plugin).to receive(:file_exist?).with("/.dockerinit").and_return(true)
       plugin.run
       expect(plugin[:virtualization][:system]).to eq("docker")
       expect(plugin[:virtualization][:role]).to eq("guest")
@@ -635,8 +635,8 @@ describe Ohai::System, "Linux virtualization platform" do
     end
 
     it "does not set virtualization if /.dockerenv or /.dockerinit does not exists" do
-      allow(File).to receive(:exist?).with("/.dockerenv").and_return(false)
-      allow(File).to receive(:exist?).with("/.dockerinit").and_return(false)
+      allow(plugin).to receive(:file_exist?).with("/.dockerenv").and_return(false)
+      allow(plugin).to receive(:file_exist?).with("/.dockerinit").and_return(false)
       plugin.run
       expect(plugin[:virtualization]).to eq({ "systems" => {} })
     end
diff --git a/spec/unit/plugins/scaleway_spec.rb b/spec/unit/plugins/scaleway_spec.rb
index f10f1ecb..1869322a 100644
--- a/spec/unit/plugins/scaleway_spec.rb
+++ b/spec/unit/plugins/scaleway_spec.rb
@@ -22,7 +22,7 @@ describe Ohai::System, "plugin scaleway" do
 
   before do
     allow(plugin).to receive(:hint?).with("scaleway").and_return(false)
-    allow(File).to receive(:exist?).with("/proc/cmdline").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/proc/cmdline").and_return(false)
   end
 
   shared_examples_for "!scaleway" do
@@ -84,8 +84,8 @@ describe Ohai::System, "plugin scaleway" do
 
   describe "with scaleway cmdline" do
     before do
-      allow(File).to receive(:exist?).with("/proc/cmdline").and_return(true)
-      allow(File).to receive(:read).with("/proc/cmdline").and_return("initrd=initrd showopts console=ttyS0,115200 nousb vga=0 root=/dev/vda scaleway boot=local")
+      allow(plugin).to receive(:file_exist?).with("/proc/cmdline").and_return(true)
+      allow(plugin).to receive(:file_read).with("/proc/cmdline").and_return("initrd=initrd showopts console=ttyS0,115200 nousb vga=0 root=/dev/vda scaleway boot=local")
     end
 
     it_behaves_like "scaleway"
diff --git a/spec/unit/plugins/shells_spec.rb b/spec/unit/plugins/shells_spec.rb
index 7002c6bc..4116f325 100644
--- a/spec/unit/plugins/shells_spec.rb
+++ b/spec/unit/plugins/shells_spec.rb
@@ -32,18 +32,18 @@ describe Ohai::System, "plugin shells" do
                 "/bin/tcsh\n",
                 "/bin/zsh\n"]
 
-  let(:shell_file_content) { shell_file }
+  let(:shell_file_content) { shell_file.join }
 
   it "does not set shells attribute if /etc/shells does not exist" do
-    allow(::File).to receive(:exist?).with("/etc/shells").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/etc/shells").and_return(false)
     plugin.run
     expect(plugin).not_to have_key(:shells)
   end
 
   it "sets shells to an array of shells if /etc/shells exists" do
-    allow(::File).to receive(:readlines).with("/etc/shells").and_return(shell_file_content)
-    allow(::File).to receive(:exist?).and_call_original
-    allow(::File).to receive(:exist?).with("/etc/shells").and_return(true)
+    allow(plugin).to receive(:file_open).with("/etc/shells").and_return(StringIO.new(shell_file_content))
+    allow(plugin).to receive(:file_exist?).and_call_original
+    allow(plugin).to receive(:file_exist?).with("/etc/shells").and_return(true)
     plugin.run
     expect(plugin.shells).to match_array([
                                            "/bin/bash",
diff --git a/spec/unit/plugins/solaris2/virtualization_spec.rb b/spec/unit/plugins/solaris2/virtualization_spec.rb
index e06211f8..ac1bd178 100644
--- a/spec/unit/plugins/solaris2/virtualization_spec.rb
+++ b/spec/unit/plugins/solaris2/virtualization_spec.rb
@@ -31,16 +31,16 @@ describe Ohai::System, "Solaris virtualization platform" do
     allow(plugin).to receive(:collect_os).and_return(:solaris2)
 
     # default to all requested Files not existing
-    allow(File).to receive(:exist?).with("/usr/sbin/psrinfo").and_return(false)
-    allow(File).to receive(:exist?).with("/usr/sbin/smbios").and_return(false)
-    allow(File).to receive(:exist?).with("/usr/sbin/zoneadm").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/usr/sbin/psrinfo").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/usr/sbin/smbios").and_return(false)
+    allow(plugin).to receive(:file_exist?).with("/usr/sbin/zoneadm").and_return(false)
     allow(plugin).to receive(:shell_out).with("/usr/sbin/smbios").and_return(mock_shell_out(0, "", ""))
     allow(plugin).to receive(:shell_out).with("#{Ohai.abs_path( "/usr/sbin/psrinfo" )} -pv").and_return(mock_shell_out(0, "", ""))
   end
 
   describe "when we are checking for kvm" do
     before do
-      expect(File).to receive(:exist?).with("/usr/sbin/psrinfo").and_return(true)
+      expect(plugin).to receive(:file_exist?).with("/usr/sbin/psrinfo").and_return(true)
     end
 
     it "runs psrinfo -pv" do
diff --git a/spec/unit/plugins/ssh_host_keys_spec.rb b/spec/unit/plugins/ssh_host_keys_spec.rb
index 80bd9727..28ddae48 100644
--- a/spec/unit/plugins/ssh_host_keys_spec.rb
+++ b/spec/unit/plugins/ssh_host_keys_spec.rb
@@ -24,27 +24,23 @@ describe Ohai::System, "ssh_host_key plugin" do
     @plugin = get_plugin("ssh_host_key")
     @plugin[:keys] = Mash.new
 
-    allow(File).to receive(:exist?).with("/etc/ssh/sshd_config").and_return(true)
-    allow(File).to receive(:open).with("/etc/ssh/sshd_config").and_yield(sshd_config_file)
-    allow(File).to receive(:exist?).and_return(true)
-    allow(File).to receive(:exist?).with("/etc/ssh/ssh_host_dsa_key.pub").and_return(true)
-    allow(File).to receive(:exist?).with("/etc/ssh/ssh_host_rsa_key.pub").and_return(true)
-    allow(File).to receive(:exist?).with("/etc/ssh/ssh_host_ecdsa_key.pub").and_return(true)
-    allow(File).to receive(:exist?).with("/etc/ssh/ssh_host_ed25519_key.pub").and_return(true)
-
-    # Ensure we can still use IO.read
-    io_read = IO.method(:read)
-    allow(IO).to receive(:read) { |file| io_read.call(file) }
+    allow(@plugin).to receive(:file_exist?).with("/etc/ssh/sshd_config").and_return(true)
+    allow(@plugin).to receive(:file_open).with("/etc/ssh/sshd_config").and_yield(sshd_config_file)
+    allow(@plugin).to receive(:file_exist?).and_return(true)
+    allow(@plugin).to receive(:file_exist?).with("/etc/ssh/ssh_host_dsa_key.pub").and_return(true)
+    allow(@plugin).to receive(:file_exist?).with("/etc/ssh/ssh_host_rsa_key.pub").and_return(true)
+    allow(@plugin).to receive(:file_exist?).with("/etc/ssh/ssh_host_ecdsa_key.pub").and_return(true)
+    allow(@plugin).to receive(:file_exist?).with("/etc/ssh/ssh_host_ed25519_key.pub").and_return(true)
 
     # Return fake public key files so we don't have to go digging for them in unit tests
     @dsa_key = "ssh-dss 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 oppa"
     @rsa_key = "ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAuhcVXV+nNapkyUC5p4TH1ymRxUjtMBKqYWmwyI29gVFnUNeHkKFHWon0KFeGJP2Rm8BfTiZa9ER9e8pRr4Nd+z1C1o0kVoxEEfB9tpSdTlpk1GG83D94l57fij8THRVIwuCEosViUlg1gDgC4SpxbqfdBkUN2qyf6JDOh7t2QpYh7berpDEWeBpb7BKdLEDT57uw7ijKzSNyaXqq8KkB9I+UFrRwpuos4W7ilX+PQ+mWLi2ZZJfTYZMxxVS+qJwiDtNxGCRwTOQZG03kI7eLBZG+igupr0uD4o6qeftPOr0kxgjoPU4nEKvYiGq8Rqd2vYrhiaJHLk9QB6xStQvS3Q== oppa"
     @ecdsa_key = "ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBBx8VgvxmHxs/sIn/ATh0iUcuz1I2Xc0e1ejXCGHBMZ98IE3FBt1ezlqCpNMcHVV2skQQ8vyLbKxzweyZuNSDU8= oppa"
     @ed25519_key = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIFYGnIM5K5JaRxbMCqz8cPMmLp57ZoJQvA5Tlj18EO6H djb"
-    allow(IO).to receive(:read).with("/etc/ssh/ssh_host_dsa_key.pub").and_return(@dsa_key)
-    allow(IO).to receive(:read).with("/etc/ssh/ssh_host_rsa_key.pub").and_return(@rsa_key)
-    allow(IO).to receive(:read).with("/etc/ssh/ssh_host_ecdsa_key.pub").and_return(@ecdsa_key)
-    allow(IO).to receive(:read).with("/etc/ssh/ssh_host_ed25519_key.pub").and_return(@ed25519_key)
+    allow(@plugin).to receive(:file_read).with("/etc/ssh/ssh_host_dsa_key.pub").and_return(@dsa_key)
+    allow(@plugin).to receive(:file_read).with("/etc/ssh/ssh_host_rsa_key.pub").and_return(@rsa_key)
+    allow(@plugin).to receive(:file_read).with("/etc/ssh/ssh_host_ecdsa_key.pub").and_return(@ecdsa_key)
+    allow(@plugin).to receive(:file_read).with("/etc/ssh/ssh_host_ed25519_key.pub").and_return(@ed25519_key)
   end
 
   shared_examples "loads keys" do
@@ -107,8 +103,8 @@ describe Ohai::System, "ssh_host_key plugin" do
     end
 
     before do
-      allow(File).to receive(:exist?).with("/etc/ssh/sshd_config").and_return(false)
-      allow(File).to receive(:exist?).with("/etc/sshd_config").and_return(false)
+      allow(@plugin).to receive(:file_exist?).with("/etc/ssh/sshd_config").and_return(false)
+      allow(@plugin).to receive(:file_exist?).with("/etc/sshd_config").and_return(false)
     end
 
     it_behaves_like "loads keys"
diff --git a/spec/unit/system_spec.rb b/spec/unit/system_spec.rb
index 62e558d4..9d02f1e7 100644
--- a/spec/unit/system_spec.rb
+++ b/spec/unit/system_spec.rb
@@ -146,7 +146,7 @@ describe "Ohai::System" do
             message("default")
           end
 
-          collect_data(:#{Ohai::Mixin::OS.collect_os}) do
+          collect_data(:#{Ohai::Mixin::OS.collect_os_local}) do
             message("platform_specific_message")
           end
         end
@@ -212,7 +212,7 @@ describe "Ohai::System" do
         Ohai.config[:plugin_path] = [ path_to(".") ]
         # Make sure the stubbing of runner is not overriden with reset_system during test
         allow(ohai).to receive(:reset_system)
-        allow(ohai.instance_variable_get("@runner")).to receive(:run_plugin).and_raise(Ohai::Exceptions::AttributeNotFound)
+        allow(ohai.runner).to receive(:run_plugin).and_raise(Ohai::Exceptions::AttributeNotFound)
         expect(ohai.logger).to receive(:error).with(/Encountered error while running plugins/)
         expect { ohai.all_plugins }.to raise_error(Ohai::Exceptions::AttributeNotFound)
       end