chef_client_systemd_timer Resource

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Use the chef_client_systemd_timer resource to setup the Chef Infra Client to run as a systemd timer.

New in Chef Infra Client 16.0.

Syntax

The full syntax for all of the properties that are available to the chef_client_systemd_timer resource is:

chef_client_systemd_timer 'name' do
  accept_chef_license      true, false # default value: false
  chef_binary_path         String # default value: "/opt/chef/bin/chef-client"
  config_directory         String # default value: "/etc/chef"
  cpu_quota                Integer, String
  daemon_options           Array # default value: []
  delay_after_boot         String # default value: "1min"
  description              String # default value: "Chef Infra Client periodic execution"
  environment              Hash # default value: {}
  interval                 String # default value: "30min"
  job_name                 String # default value: "chef-client"
  run_on_battery           true, false # default value: true
  splay                    String # default value: "5min"
  user                     String # default value: "root"
  action                   Symbol # defaults to :add if not specified
end

where:

• chef_client_systemd_timer is the resource.
• name is the name given to the resource block.
• action identifies which steps Chef Infra Client will take to bring the node into the desired state.
• accept_chef_license, chef_binary_path, config_directory, cpu_quota, daemon_options, delay_after_boot, description, environment, interval, job_name, run_on_battery, splay, and user are the properties available to this resource.

Actions

The chef_client_systemd_timer resource has the following actions:

:add

Add a systemd timer that runs Chef Infra Client. (default)

: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.

:remove

Remove a systemd timer that runs Chef Infra Client.

Properties

The chef_client_systemd_timer resource has the following properties:

accept_chef_license

Ruby Type: true, false | Default Value: false

Accept the Chef Online Master License and Services Agreement. See https://www.chef.io/online-master-agreement

chef_binary_path

Ruby Type: String | Default Value: /opt/chef/bin/chef-client

The path to the chef-client binary.

config_directory

Ruby Type: String | Default Value: /etc/chef

The path of the config directory.

cpu_quota

Ruby Type: Integer, String

The systemd CPUQuota to run the chef-client process with. This is a percentage value of the total CPU time available on the system. If the system has more than 1 core this may be a value greater than 100.

New in Chef Infra Client 16.5

daemon_options

Ruby Type: Array | Default Value: []

An array of options to pass to the chef-client command.

delay_after_boot

Ruby Type: String | Default Value: 1min

The time to wait after booting before the interval starts. This is expressed as a systemd time span such as 300seconds, 1hr, or 1m. See https://www.freedesktop.org/software/systemd/man/systemd.time.html for a complete list of allowed time span values.

description

Ruby Type: String | Default Value: Chef Infra Client periodic execution

The description to add to the systemd timer. This will be displayed when running systemctl status for the timer.

environment

Ruby Type: Hash | Default Value: {}

A Hash containing additional arbitrary environment variables under which the systemd timer will be run in the form of ({'ENV_VARIABLE' => 'VALUE'}).

interval

Ruby Type: String | Default Value: 30min

The interval to wait between executions. This is expressed as a systemd time span such as 300seconds, 1hr, or 1m. See https://www.freedesktop.org/software/systemd/man/systemd.time.html for a complete list of allowed time span values.

job_name

Ruby Type: String | Default Value: chef-client

The name of the system timer to create.

run_on_battery

Ruby Type: true, false | Default Value: true

Run the timer for Chef Infra Client if the system is on battery.

splay

Ruby Type: String | Default Value: 5min

A interval between 0 and X to add to the interval so that all chef-client commands don’t execute at the same time. This is expressed as a systemd time span such as 300seconds, 1hr, or 1m. See https://www.freedesktop.org/software/systemd/man/systemd.time.html for a complete list of allowed time span values.

user

Ruby Type: String | Default Value: root

The name of the user that Chef Infra Client runs as.

Common Resource Functionality

Chef resources include common properties, notifications, and resource guards.

Common Properties

The following properties are common to every resource:

compile_time

Ruby Type: true, false | Default Value: false

Control the phase during which the resource is run on the node. Set to true to run while the resource collection is being built (the compile phase). Set to false to run while Chef Infra Client is configuring the node (the converge phase).

ignore_failure

Ruby Type: true, false, :quiet | Default Value: false

Continue running a recipe if a resource fails for any reason. :quiet will not display the full stack trace and the recipe will continue to run if a resource fails.

retries

Ruby Type: Integer | Default Value: 0

The number of attempts to catch exceptions and retry the resource.

retry_delay

Ruby Type: Integer | Default Value: 2

The delay in seconds between retry attempts.

sensitive

Ruby Type: true, false | Default Value: false

Ensure that sensitive resource data is not logged by Chef Infra Client.

Notifications

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

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

Guards

A guard property can be used to evaluate the state of a node during the execution phase of a Chef Infra Client run. Based on the results of this evaluation, a guard property is then used to tell Chef Infra Client if it should continue executing a resource. A guard property accepts either a string value or a Ruby block value:

• A string is executed as a shell command. If the command returns 0, the guard is applied. If the command returns any other value, then the guard property is not applied. String guards in a powershell_script run Windows PowerShell commands and may return true in addition to 0.
• A block is executed as Ruby code that must return either true or false. If the block returns true, the guard property is applied. If the block returns false, the guard property is not applied.

A guard property is useful for ensuring that a resource is idempotent by allowing that resource to test for the desired state as it is being executed, and then if the desired state is present, for Chef Infra Client to do nothing.

The following properties can be used to define a guard that is evaluated during the execution phase of a Chef Infra Client run:

not_if

Prevent a resource from executing when the condition returns true.

only_if

Allow a resource to execute only if the condition returns true.

Examples

The following examples demonstrate various approaches for using the chef_client_systemd_timer resource in recipes:

Setup Chef Infra Client to run using the default 30 minute cadence:

chef_client_systemd_timer 'Run Chef Infra Client as a systemd timer'

Run Chef Infra Client every 1 hour:

chef_client_systemd_timer 'Run Chef Infra Client every 1 hour' do
  interval '1hr'
end

Run Chef Infra Client with extra options passed to the client:

chef_client_systemd_timer 'Run an override recipe' do
  daemon_options ['--override-runlist mycorp_base::default']
end