Avoid Errno::EBUSY on docker containers

This commit fixes https://github.com/chef/chef/issues/4949 by adding
ohai-based docker detection code and statically checking for
/etc/hostname or /etc/resolv.conf.

1 files changed, 13 insertions, 1 deletions

diff --git a/lib/chef/provider/file.rb b/lib/chef/provider/file.rb
index 7f85085eeb..8b3884f710 100644
--- a/lib/chef/provider/file.rb
+++ b/lib/chef/provider/file.rb
@@ -67,7 +67,13 @@ class Chef
       def initialize(new_resource, run_context)
         @content_class ||= Chef::Provider::File::Content
         if new_resource.respond_to?(:atomic_update)
-          @deployment_strategy = Chef::FileContentManagement::Deploy.strategy(new_resource.atomic_update)
+          # Resolves https://github.com/chef/chef/issues/4949
+          if docker_guest?(run_context.node) && (new_resource.path == "/etc/resolv.conf" ||
+                                                 new_resource.path == "/etc/hostname")
+            @deployment_strategy = Chef::FileContentManagement::Deploy.strategy(false)
+          else
+            @deployment_strategy = Chef::FileContentManagement::Deploy.strategy(new_resource.atomic_update)
+          end
         end
         super
       end
@@ -193,6 +199,12 @@ class Chef
 
       private
 
+      # Return true if we are running in a docker guest, or false otherwise.
+      def docker_guest?(node)
+        node[:virtualization] && node[:virtualization][:systems] &&
+          node[:virtualization][:systems][:docker] && node[:virtualization][:systems][:docker] == "guest"
+      end
+
       # What to check in this resource to see if we're going to be actively managing
       # content (for things like doing checksums in load_current_resource).  Expected to
       # be overridden in subclasses.