Fix sysctl :remove action failing with missing :value prop

Don't require this when removing.

Signed-off-by: Tim Smith <tsmith@chef.io>

7 files changed, 78 insertions, 5 deletions

diff --git a/kitchen-tests/cookbooks/end_to_end/recipes/alternatives.rb b/kitchen-tests/cookbooks/end_to_end/recipes/_alternatives.rb
index 8e0a0bb178..8e0a0bb178 100644
--- a/kitchen-tests/cookbooks/end_to_end/recipes/alternatives.rb
+++ b/kitchen-tests/cookbooks/end_to_end/recipes/_alternatives.rb
diff --git a/kitchen-tests/cookbooks/end_to_end/recipes/chef-vault.rb b/kitchen-tests/cookbooks/end_to_end/recipes/_chef-vault.rb
index aa01982e3d..aa01982e3d 100644
--- a/kitchen-tests/cookbooks/end_to_end/recipes/chef-vault.rb
+++ b/kitchen-tests/cookbooks/end_to_end/recipes/_chef-vault.rb
diff --git a/kitchen-tests/cookbooks/end_to_end/recipes/packages.rb b/kitchen-tests/cookbooks/end_to_end/recipes/_packages.rb
index 58ede61f52..58ede61f52 100644
--- a/kitchen-tests/cookbooks/end_to_end/recipes/packages.rb
+++ b/kitchen-tests/cookbooks/end_to_end/recipes/_packages.rb
diff --git a/kitchen-tests/cookbooks/end_to_end/recipes/_sysctl.rb b/kitchen-tests/cookbooks/end_to_end/recipes/_sysctl.rb
new file mode 100644
index 0000000000..8c644e01c6
--- /dev/null
+++ b/kitchen-tests/cookbooks/end_to_end/recipes/_sysctl.rb
@@ -0,0 +1,12 @@
+#
+# Cookbook:: end_to_end
+# Recipe:: sysctl
+#
+
+sysctl "vm.swappiness" do
+  value 19
+end
+
+sysctl "kernel.msgmax" do
+  action :remove
+end
\ No newline at end of file
diff --git a/kitchen-tests/cookbooks/end_to_end/recipes/tests.rb b/kitchen-tests/cookbooks/end_to_end/recipes/_tests.rb
index d74a310394..d74a310394 100644
--- a/kitchen-tests/cookbooks/end_to_end/recipes/tests.rb
+++ b/kitchen-tests/cookbooks/end_to_end/recipes/_tests.rb
diff --git a/kitchen-tests/cookbooks/end_to_end/recipes/default.rb b/kitchen-tests/cookbooks/end_to_end/recipes/default.rb
index 54750039c5..6378d55bcc 100644
--- a/kitchen-tests/cookbooks/end_to_end/recipes/default.rb
+++ b/kitchen-tests/cookbooks/end_to_end/recipes/default.rb
@@ -40,7 +40,7 @@ build_essential do
   raise_if_unsupported true
 end
 
-include_recipe "::packages"
+include_recipe "::_packages"
 
 include_recipe "ntp"
 
@@ -158,6 +158,7 @@ locale "set system locale" do
   only_if { debian? }
 end
 
-include_recipe "::chef-vault" unless includes_recipe?("end_to_end::chef-vault")
-include_recipe "::alternatives"
-include_recipe "::tests"
+include_recipe "::_chef-vault" unless includes_recipe?("end_to_end::chef-vault")
+include_recipe "::_sysctl"
+include_recipe "::_alternatives"
+include_recipe "::_tests"
diff --git a/lib/chef/resource/sysctl.rb b/lib/chef/resource/sysctl.rb
index c2ac8224b4..78d1072ddb 100644
--- a/lib/chef/resource/sysctl.rb
+++ b/lib/chef/resource/sysctl.rb
@@ -30,6 +30,66 @@ class Chef
                   "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."
+      examples <<~DOC
+      **Set vm.swappiness**:
+
+      ```ruby
+      sysctl 'vm.swappiness' do
+        value 19
+      end
+      ```
+
+      **Remove kernel.msgmax**
+
+      **Note**: This only removes the sysctl.d config for kernel.msgmax. The value will be set back to the kernel default value.
+
+      ```ruby
+      sysctl 'kernel.msgmax' do
+        action :remove
+      end
+      ```
+
+      **Adding Comments to sysctl configuration files**
+
+      ```ruby
+      sysctl 'vm.swappiness' do
+        value 19
+        comment "define how aggressively the kernel will swap memory pages."
+      end
+      ```
+
+      This produces /etc/sysctl.d/99-chef-vm.swappiness.conf as follows:
+
+      ```
+      # define how aggressively the kernel will swap memory pages.
+      vm.swappiness = 1
+      ```
+
+      **Converting sysctl settings from shell scripts**:
+
+      Example of existing settings:
+
+      ```bash
+      fs.aio-max-nr = 1048576 net.ipv4.ip_local_port_range = 9000 65500 kernel.sem = 250 32000 100 128
+      ```
+
+      Converted to sysctl resources:
+
+      ```ruby
+      sysctl 'fs.aio-max-nr' do
+        value '1048576'
+      end
+
+      sysctl 'net.ipv4.ip_local_port_range' do
+        value '9000 65500'
+      end
+
+      sysctl 'kernel.sem' do
+        value '250 32000 100 128'
+      end
+      ```
+      DOC
+
 
       introduced "14.0"
 
@@ -44,7 +104,7 @@ class Chef
       property :value, [Array, String, Integer, Float],
         description: "The value to set.",
         coerce: proc { |v| coerce_value(v) },
-        required: true
+        required: %i(:apply)
 
       property :comment, [Array, String],
         description: "Comments, placed above the resource setting in the generated file. For multi-line comments, use an array of strings, one per line.",