summaryrefslogtreecommitdiff
path: root/lib/chef/resource/sysctl.rb
blob: 643ceb233a75986fc3c96e99ea7c283e1eb1e870 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
#
# Copyright:: 2018, Webb Agile Solutions Ltd.
# Copyright:: 2018-2018, Chef Software Inc.
#
# 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/resource"

class Chef
  class Resource
    class Sysctl < Chef::Resource
      resource_name :sysctl
      provides(:sysctl) { true }
      provides(:sysctl_param) { true }

      description "Use the sysctl resource to set kernel parameters using the sysctl"\
                  " command line tool and configuration files in the system's sysctl.d directory. "\
                  "Configuration files managed by this resource are named 99-chef-KEYNAME.conf. If"\
                  " an existing value was already set for the value it will be backed up to the node"\
                  " and restored if the :remove action is used later."

      introduced "14.0"

      property :key, String,
               description: "The kernel parameter key in dotted format, if it differs from the resource block name.",
               name_property: true

      property :ignore_error, [TrueClass, FalseClass],
               description: "Ignore any errors when setting the value on the command line.",
               default: false, desired_state: false

      property :value, [Array, String, Integer, Float],
               description: "The value to set.",
               coerce: proc { |v| coerce_value(v) },
               required: true

      property :conf_dir, String,
               description: "The configuration directory to write the config to.",
               default: "/etc/sysctl.d"

      def after_created
        raise "The sysctl resource requires Linux as it needs sysctl and the sysctl.d directory functionality." unless node["os"] == "linux"
        raise "The sysctl resource does not support SLES releases less than 12 as it requires a sysctl.d directory" if platform_family?("suse") && node["platform_version"].to_i < 12
      end

      def coerce_value(v)
        case v
        when Array
          v.join(" ")
        else
          v.to_s
        end
      end

      load_current_value do
        begin
          value get_sysctl_value(key)
        rescue
          current_value_does_not_exist!
        end
      end

      action :apply do
        description "Apply a sysctl value."

        converge_if_changed do
          # set it temporarily
          set_sysctl_param(new_resource.key, new_resource.value)

          directory new_resource.conf_dir

          file "#{new_resource.conf_dir}/99-chef-#{new_resource.key}.conf" do
            content "#{new_resource.key} = #{new_resource.value}"
          end

          execute "Load sysctl values" do
            command "sysctl #{'-e ' if new_resource.ignore_error}-p"
            default_env true
            action :run
          end
        end
      end

      action :remove do
        description "Remove a sysctl value."

        # only converge the resource if the file actually exists to delete
        if ::File.exist?("#{new_resource.conf_dir}/99-chef-#{new_resource.key}.conf")
          converge_by "removing sysctl config at #{new_resource.conf_dir}/99-chef-#{new_resource.key}.conf" do
            file "#{new_resource.conf_dir}/99-chef-#{new_resource.key}.conf" do
              action :delete
            end

            execute "Load sysctl values" do
              default_env true
              command "sysctl -p"
              action :run
            end
          end
        end
      end

      action_class do
        def set_sysctl_param(key, value)
          shell_out!("sysctl #{'-e ' if new_resource.ignore_error}-w \"#{key}=#{value}\"")
        end
      end

      private

      # shellout to sysctl to get the current value
      # ignore missing keys by using '-e'
      # convert tabs to spaces since sysctl tab deliminates multivalue parameters
      # strip the newline off the end of the output as well
      #
      # Chef creates a file in sysctld with parameter configuration
      # Thus this config will persists even after rebooting the system
      # User can be in a half configured state, where he has already updated the value
      # which he wants to be configured from the resource
      # Therefore we need an extra check with sysctld to ensure a correct idempotency
      #
      def get_sysctl_value(key)
        val = shell_out!("sysctl -n -e #{key}").stdout.tr("\t", " ").strip
        raise unless val == get_sysctld_value(key)
        val
      end

      # Check if chef has already configured a value for the given key and
      # return the value. Raise in case this conf file needs to be created
      # or updated
      def get_sysctld_value(key)
        raise unless ::File.exist?("/etc/sysctl.d/99-chef-#{key}.conf")
        k, v = ::File.read("/etc/sysctl.d/99-chef-#{key}.conf").match(/(.*) = (.*)/).captures
        raise "Unknown sysctl key!" if k.nil?
        raise "Unknown sysctl value!" if v.nil?
        v
      end
    end
  end
end