ohai_hint resource

[edit on GitHub]

Use the ohai_hint resource to aid in configuration detection by passing hint data to Ohai.

New in Chef Client 14.0.

Syntax

The ohai_hint resource has the following syntax:

ohai_hint 'name' do
  compile_time      true, false # default value: true
  content           Hash
  hint_name         String # default value: 'name' unless specified
  action            Symbol # defaults to :create if not specified
end

where:

  • ohai_hint is the resource.
  • name is the name given to the resource block.
  • action identifies which steps the chef-client will take to bring the node into the desired state.
  • compile_time, content, and hint_name are the properties available to this resource.

Actions

The ohai_hint resource has the following actions:

:create
Default. Create an Ohai hint file.
:delete
Delete an Ohai hint file.
:nothing
Define this resource block to do nothing until notified by another resource to take action. When this resource is notified, the resource block is either run immediately or it is queued up to be run at the end of the Chef Client run.

Properties

compile_time

Ruby Type: true, false | Default Value: true

Determines whether or not the resource is executed during the compile time phase.

content

Ruby Type: Hash

Values to include in the hint file.

hint_name

Ruby Type: String

The name of the hints file, if it differs from the resource name.

notifies

Ruby Type: Symbol, ‘Chef::Resource[String]’

A resource may notify another resource to take action when its state changes. Specify a 'resource[name]', the :action that resource should take, and then the :timer for that action. A resource may notify more than one resource; use a notifies statement for each resource to be notified.

A timer specifies the point during the Chef Client run at which a notification is run. The following timers are available:

:before
Specifies that the action on a notified resource should be run before processing the resource block in which the notification is located.
:delayed
Default. Specifies that a notification should be queued up, and then executed at the end of the Chef Client run.
:immediate, :immediately
Specifies that a notification should be run immediately, per resource notified.

The syntax for notifies is:

notifies :action, 'resource[name]', :timer
subscribes

Ruby Type: Symbol, ‘Chef::Resource[String]’

A resource may listen to another resource, and then take action if the state of the resource being listened to changes. Specify a 'resource[name]', the :action to be taken, and then the :timer for that action.

Note that subscribes does not apply the specified action to the resource that it listens to - for example:

file '/etc/nginx/ssl/example.crt' do
   mode '0600'
   owner 'root'
end

service 'nginx' do
   subscribes :reload, 'file[/etc/nginx/ssl/example.crt]', :immediately
end

In this case the subscribes property reloads the nginx service whenever its certificate file, located under /etc/nginx/ssl/example.crt, is updated. subscribes does not make any changes to the certificate file itself, it merely listens for a change to the file, and executes the :reload action for its resource (in this example nginx) when a change is detected.

A timer specifies the point during the Chef Client run at which a notification is run. The following timers are available:

:before
Specifies that the action on a notified resource should be run before processing the resource block in which the notification is located.
:delayed
Default. Specifies that a notification should be queued up, and then executed at the end of the Chef Client run.
:immediate, :immediately
Specifies that a notification should be run immediately, per resource notified.

The syntax for subscribes is:

subscribes :action, 'resource[name]', :timer

Examples

Create a hint file

ohai_hint 'example' do
  content Hash[:a, 'test_content']
end

Create a hint file with a name that does not match the resource name

ohai_hint 'example' do
  hint_name 'custom'
end

Create a hint file that is not loaded at compile time

ohai_hint 'example' do
  compile_time false
end

Delete a hint file

ohai-hint 'example' do
  action :delete
end