chef_role Resource

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A role is a way to define certain patterns and processes that exist across nodes in an organization as belonging to a single job function. Each role consists of zero (or more) attributes and a run-list. Each node can have zero (or more) roles assigned to it. When a role is run against a node, the configuration details of that node are compared against the attributes of the role, and then the contents of that role’s run-list are applied to the node’s configuration details. When a Chef Infra Client runs, it merges its own attributes and run-lists with those contained within each assigned role.

Use the chef_role resource to manage roles.

Syntax

The syntax for using the chef_role resource in a recipe is as follows:

chef_role 'name' do
  attribute 'value' # see properties section below
  ...
  action :action # see actions section below
end

where:

• chef_role tells Chef Infra Client to use the Chef::Provider::ChefRole provider during a Chef Infra Client run
• name is the name of the resource block; when the name property is not specified as part of a recipe, name is also the name of the role
• attribute is zero (or more) of the properties that are available for this resource
• action identifies which steps Chef Infra Client will take to bring the node into the desired state

Actions

The chef_role resource has the following actions:

:create

Default. Use to create a role.

:delete

Use to delete a role.

:nothing

This resource block does not act unless notified by another resource to take action. Once notified, this resource block either runs immediately or is queued up to run at the end of a Chef Infra Client run.

Properties

The chef_role resource has the following properties:

chef_server

The URL for the Chef Infra Server.

complete

Use to specify if this resource defines a role completely. When true, any property not specified by this resource will be reset to default property values.

default_attributes

A default attribute is automatically reset at the start of every Chef Infra Client run and has the lowest attribute precedence. Use default attributes as often as possible in cookbooks.

Default value: {}.

description

The description of the role. This value populates the description field for the role on the Chef Infra Server.

env_run_lists

The environment-specific run-list for a role. Default value: []. For example: ["env_run_lists[webserver]"]

ignore_failure

Ruby Type: true, false | Default Value: false

Continue running a recipe if a resource fails for any reason.

name

The name of the role.

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.

If the referenced resource does not exist, an error is raised. In contrast, subscribes will not fail if the source resource is not found.

A timer specifies the point during a Chef Infra 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 a Chef Infra Client run.

:immediate, :immediately

Specifies that a notification should be run immediately, for each resource notified.

The syntax for notifies is:

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

override_attributes

An override attribute is automatically reset at the start of every Chef Infra Client run and has a higher attribute precedence than default, force_default, and normal attributes. An override attribute is most often specified in a recipe, but can be specified in an attribute file, for a role, and/or for an environment. A cookbook should be authored so that it uses override attributes only when required.

Default value: {}.

raw_json

The role as JSON data. For example:

{
  "name": "webserver",
  "chef_type": "role",
  "json_class": "Chef::Role",
  "default_attributes": {},
  "description": "A webserver",
  "run_list": [
    "recipe[apache2]"
  ],
  "override_attributes": {}
}

run_list

A comma-separated list of roles and/or recipes to be applied. Default value: []. For example: ["recipe[default]","recipe[apache2]"]

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.

If the other resource does not exist, the subscription will not raise an error. Contrast this with the stricter semantics of notifies, which will raise an error if the other resource does not exist.

A timer specifies the point during a Chef Infra 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 a Chef Infra Client run.

:immediate, :immediately

Specifies that a notification should be run immediately, for each resource notified.

The syntax for subscribes is:

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

Examples

This resource does not have any examples.