habitat_service Resource

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Use the habitat_service resource to manage Chef Habitat services. This requires that core/hab-sup be running as a service. See the habitat_sup resource documentation for more information.

New in Chef Infra Client 17.3.

Syntax

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

habitat_service 'name' do
  bind                       String, Array # default value: []
  binding_mode               Symbol, String # default value: :strict
  bldr_url                   String # default value: "https://bldr.habitat.sh/"
  channel                    Symbol, String # default value: :stable
  gateway_auth_token         String
  health_check_interval      Integer # default value: 30
  remote_sup                 String # default value: "127.0.0.1:9632"
  remote_sup_http            String # default value: "127.0.0.1:9631"
  service_group              String # default value: "default"
  service_name               String # default value: 'name' unless specified
  shutdown_timeout           Integer # default value: 8
  strategy                   Symbol, String # default value: :none
  topology                   Symbol, String # default value: :standalone
  update_condition           Symbol, String # default value: :latest
  action                     Symbol # defaults to :load if not specified
end

where:

• habitat_service 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.
• bind, binding_mode, bldr_url, channel, gateway_auth_token, health_check_interval, remote_sup, remote_sup_http, service_group, service_name, shutdown_timeout, strategy, topology, and update_condition are the properties available to this resource.

Actions

The habitat_service resource has the following actions:

:load

(default action) runs hab service load to load and start the specified application service (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.

:reload

runs the :unload and then :load actions

:restart

runs the :stop and then :start actions

:start

runs hab service start to start the specified application service

:stop

runs hab service stop to stop the specified application service

:unload

runs hab service unload to unload and stop the specified application service

Properties

The habitat_service resource has the following properties:

bind

Ruby Type: String, Array | Default Value: []

Passes --bind with the specified services to bind to the hab command. If an array of multiple service binds are specified then a --bind flag is added for each.

binding_mode

Ruby Type: Symbol, String | Default Value: :strict
Allowed Values: :strict, "strict", :relaxed, "relaxed"

Passes --binding-mode with the specified binding mode. Defaults to :strict. Options are :strict or :relaxed

bldr_url

Ruby Type: String | Default Value: https://bldr.habitat.sh/

Passes --url with the specified Habitat Builder URL to the hab command. Depending on the type of Habitat Builder you are connecting to, this URL will look different, here are the 3 current types: - Public Habitat Builder (default) - https://bldr.habitat.sh - On-Prem Habitat Builder installed using the Source Install Method - https://your.bldr.url - On-Prem Habitat Builder installed using the Automate Installer - https://your.bldr.url/bldr/v1

channel

Ruby Type: Symbol, String | Default Value: :stable

Passes --channel with the specified channel to the hab command

gateway_auth_token

Ruby Type: String

Auth token for accessing the remote supervisor’s http port.

health_check_interval

Ruby Type: Integer | Default Value: 30

The interval (seconds) on which to run health checks.

remote_sup

Ruby Type: String | Default Value: 127.0.0.1:9632

Address to a remote Supervisor’s Control Gateway

remote_sup_http

Ruby Type: String | Default Value: 127.0.0.1:9631

IP address and port used to communicate with the remote supervisor. If this value is invalid, the resource will update the supervisor configuration each time Chef Infra Server runs.

service_group

Ruby Type: String | Default Value: default

Passes --group with the specified service group to the hab command

service_name

Ruby Type: String | Default Value: The resource block's name

The name of the service, must be in the form of origin/name

shutdown_timeout

Ruby Type: Integer | Default Value: 8

The timeout in seconds allowed during shutdown.

strategy

Ruby Type: Symbol, String | Default Value: :none
Allowed Values: :none, "none", :"at-once", "at-once", :rolling, "rolling"

Passes --strategy with the specified update strategy to the hab command. Defaults to :none. Other options are :'at-once' and :rolling

topology

Ruby Type: Symbol, String | Default Value: :standalone
Allowed Values: :standalone, "standalone", :leader, "leader"

Passes --topology with the specified service topology to the hab command

update_condition

Ruby Type: Symbol, String | Default Value: :latest
Allowed Values: :latest, "latest", :"track-channel", "track-channel"

Passes --update-condition dictating when this service should updated. Defaults to latest. Options are latest or track-channel **_

Note

This requires a minimum habitat version of 1.5.71_** - latest: Runs the latest package that can be found in the configured channel and local packages. - track-channel: Always run the package at the head of a given channel. This enables service rollback, where demoting a package from a channel will cause the package to rollback to an older version of the package. A ramification of enabling this condition is that packages that are newer than the package at the head of the channel are also uninstalled during a service rollback.

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 habitat_service resource in recipes:

Install and load nginx

habitat_package 'core/nginx'
habitat_service 'core/nginx'

habitat_service 'core/nginx unload' do
  service_name 'core/nginx'
  action :unload
end

Pass the strategy and topology options to hab service commands

habitat_service 'core/redis' do
  strategy 'rolling'
  topology 'standalone'
end

Using update_condition

habitat_service 'core/redis' do
  strategy 'rolling'
  update_condition 'track-channel'
  topology 'standalone'
end

If the service has it’s own user specified that is not the hab user, don’t create the hab user on install, and instead create the application user with Chef’s user resource

habitat_install 'install habitat' do
  create_user false
end

user 'acme-apps' do
  system true
end

habitat_service 'acme/apps'