systemd_unit Resource
This page is generated from the Chef Infra Client source code.To suggest a change, edit the systemd_unit.rb file and submit a pull request to the Chef Infra Client repository.
Use the systemd_unit resource to create, manage, and run systemd units.
New in Chef Infra Client 12.11.
Syntax
The full syntax for all of the properties that are available to the systemd_unit resource is:
systemd_unit 'name' do
content String, Hash
triggers_reload true, false # default value: true
unit_name String # default value: 'name' unless specified
user String
verify true, false # default value: true
action Symbol # defaults to :nothing if not specified
end
where:
systemd_unit
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.content
,triggers_reload
,unit_name
,user
, andverify
are the properties available to this resource.
Actions
The systemd_unit resource has the following actions:
:create
- Create a systemd unit file, if it does not already exist.
:delete
- Delete a systemd unit file, if it exists.
:disable
- Ensure the unit will not be started after the next system boot.
:enable
- Ensure the unit will be started after the next system boot.
:mask
- Ensure the unit will not start, even to satisfy dependencies.
: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. (default)
:preset
- Restore the preset ‘
enable
/disable
’ configuration for a systemd unit. New in Chef Infra Client 14.0. :reenable
- Reenable a unit file. New in Chef Infra Client 14.0.
:reload
- Reload the configuration file for a systemd unit.
:reload_or_restart
- For systemd units that are services, this action reloads the configuration of the service without restarting, if possible; otherwise, it will restart the service so the new configuration is applied.
:reload_or_try_restart
- For systemd units that are services, this action reloads the configuration of the service without restarting, if possible; otherwise, it will try to restart the service so the new configuration is applied.
:restart
- Restart a systemd unit.
:revert
- Revert to a vendor’s version of a systemd unit file. New in Chef Infra Client 14.0.
:start
- Start a systemd unit.
:stop
- Stop a running systemd unit.
:try_restart
- Try to restart a systemd unit if the unit is running.
:unmask
- Stop the unit from being masked and cause it to start as specified.
Properties
The systemd_unit resource has the following properties:
content
- Ruby Type: String, Hash
A string or hash that contains a systemd unit file definition that describes the properties of systemd-managed entities, such as services, sockets, devices, and so on. In Chef Infra Client 14.4 or later, repeatable options can be implemented with an array.
triggers_reload
- Ruby Type: true, false | Default Value:
true
Specifies whether to trigger a daemon reload when creating or deleting a unit.
unit_name
- Ruby Type: String | Default Value:
The resource block's name
The name of the unit file if it differs from the resource block’s name.
New in Chef Client 13.7
user
- Ruby Type: String
The user account that the systemd unit process is run under. The path to the unit for that user would be something like ‘/etc/systemd/user/sshd.service’. If no user account is specified, the systemd unit will run under a ‘system’ account, with the path to the unit being something like ‘/etc/systemd/system/sshd.service’.
verify
- Ruby Type: true, false | Default Value:
true
Specifies if the unit will be verified before installation. Systemd can be overly strict when verifying units, so in certain cases it is preferable not to verify the unit.
Unit file verification
The unit file is verified using a systemd-analyze verify
call before
being written to disk.
Be aware that the referenced commands and files need to already exist before verification.
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 (theconverge 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 anotifies
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 returntrue
in addition to0
. - A block is executed as Ruby code that must return either
true
orfalse
. If the block returnstrue
, the guard property is applied. If the block returnsfalse
, 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.
PropertiesThe 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 systemd_unit resource in recipes:
Create systemd service unit file from a Hash
systemd_unit 'etcd.service' do
content({ Unit: {
Description: 'Etcd',
Documentation: ['https://coreos.com/etcd', 'man:etcd(1)'],
After: 'network.target',
},
Service: {
Type: 'notify',
ExecStart: '/usr/local/etcd',
Restart: 'always',
},
Install: {
WantedBy: 'multi-user.target',
} })
action [:create, :enable]
end
Create systemd service unit file from a String
systemd_unit 'sysstat-collect.timer' do
content <<~EOU
[Unit]
Description=Run system activity accounting tool every 10 minutes
[Timer]
OnCalendar=*:00/10
[Install]
WantedBy=sysstat.service
EOU
action [:create, :enable]
end