chef_node

[edit on GitHub]

Warning

This functionality is available with Chef provisioning and is packaged in the Chef development kit. Chef provisioning is a framework that allows clusters to be managed by the chef-client and the Chef server in the same way nodes are managed: with recipes. Use Chef provisioning to describe, version, deploy, and manage clusters of any size and complexity using a common set of tools.

A node is any machine—physical, virtual, cloud, network device, etc.—that is under management by Chef.

Use the chef_node resource to manage nodes.

Syntax

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

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

where

  • chef_node tells the chef-client to use the Chef::Provider::ChefNode provider during the chef-client run
  • name is the name of the resource block
  • attribute is zero (or more) of the properties that are available for this resource
  • action identifies which steps the chef-client will take to bring the node into the desired state

Actions

This resource has the following actions:

:create
Default. Use to create a node.
:delete
Use to delete a node.
:nothing
Define this resource block to do nothing until notified by another resource to take action. When this resource is notified, this resource block is either run immediately or it is queued up to be run at the end of the chef-client run.

Properties

This resource has the following properties:

automatic_attributes

An automatic attribute contains data that is identified by Ohai at the beginning of every chef-client run. An automatic attribute cannot be modified and always has the highest attribute precedence.

Default value: {}.

chef_environment
The Chef server environment in which this node should exist (or does exist).
chef_server
The URL for the Chef server.
complete
Use to specify if this resource defines a node 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-client run and has the lowest attribute precedence. Use default attributes as often as possible in cookbooks.

Default value: {}.

ignore_failure

Ruby Types: TrueClass, FalseClass

Continue running a recipe if a resource fails for any reason. Default value: false.

name
The name of the node.
normal_attributes

A normal attribute is a setting that persists in the node object. A normal attribute has a higher attribute precedence than a default attribute.

Default value: {}.

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 very 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
override_attributes

An override attribute is automatically reset at the start of every chef-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 node as JSON data. For example:

{
  "overrides": {},
  "name": "latte",
  "chef_type": "node",
  "json_class": "Chef::Node",
  "attributes": {
    "hardware_type": "laptop"
  },
  "run_list": [
    "recipe[apache2]"
  ],
  "defaults": {}
}
retries

Ruby Type: Integer

The number of times to catch exceptions and retry the resource. Default value: 0.

retry_delay

Ruby Type: Integer

The retry delay (in seconds). Default value: 2.

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.

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 very 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

None.