systemd

Ansible Role: systemd

This role provides a simple yet flexible way to manage all systemd unit files.

Features

• Create all systemd unit files.
• Create template units.
• Set all unit directives.
• Enable/Disable each unit.
• Restart units on change.

Requirements

• Ansible 2.8 or higher.

Role Variables

Available variables are listed below, along with default values (see defaults/main.yml):

systemd_units: []

A list of dictionaries. For each unit, you must provide a name, all other keys are listed in the syntax heading below.

systemd_units_restart_changed: yes

Whether to restart the unit on file change. You can also specify the parameter restart_changed for each unit. Template units will always be skipped.

systemd_units_enabled: yes

Whether to enable units on boot. You can also specify the parameter enabled for each unit. Template units will always be skipped.

Syntax

A systemd_unit has all the parameters of the systemd module plus multiple keys ending with _section, you can specify as many sections as you want. Each section is a dictionary of configuration directives. If no section is provided, an empty file will be created. Use this as an effective way to fully disable a unit.

- name: foo.service
  scope: user
  # other systemd module parameters...
  Unit_section:
    Description: Foo
  Service_section:
    ExecStart: /usr/sbin/foo-daemon
  Install_section:
    WantedBy: multi-user.target

The unit above will create a foo.service file with following content:

[Unit]
Description=Foo

[Service]
ExecStart=/usr/sbin/foo-daemon

[Install]
WantedBy=multi-user.target

A directive key can be a string, a list or a dictionary, each key type will be converted as follows:

ExecStart: "/usr/bin/foo-daemon"
Wants:
  - [email protected]
  - [email protected]
Environment:
  VAR1: word1 word2
  VAR2: word3
  VAR3: $word 5 6

ExecStart=/usr/bin/foo-daemon
[email protected]
[email protected]
Environment="VAR1=word1 word2"
Environment="VAR2=word3"
Environment="VAR3=$word 5 6"

Convert snake_case keys to PascalCase

systemd_convert_snake_case_keys: yes

This variable allows you to write all directives in snake_case. When enabled, this role will convert all snake_case directives to PascalCase, e.g. exec_start: "/usr/bin/foo-daemon" will be converted to ExecStart=/usr/bin/foo-daemon. If you don't like this feature you can disable it.

systemd_readable_snake_case_keys: # see defaults/main.yml

This role maintains a dictionary of readable snake_case directives. In fact, some directives are abbreviated, to write CPUShares in snake case, you have to write c_p_u_shares. Thanks to this variable, you can to write cpu_shares.

Dependencies

None.

Example Playbook

This is a sample playbook file for creating and starting a service unit sleep.service.

- hosts: all
  become: true
  vars:
    systemd_units:
      - name: sleep.service
        Service_section:
          ExecStart: /bin/sleep 300
        Install_section:
          WantedBy: multi-user.target
  roles:
    - { role: anasbouzid.systemd, tags: [systemd] }

This is a sample systemd_units variable for creating and starting a target unit sleep.target that instantiates 3 service templates.

systemd_units:
  - name: [email protected]
    Unit_section:
      Description: Sleep for %i seconds
      PartOf: sleep.target
    Service_section:
      Restart: always
      ExecStart: /bin/sleep %i
    Install_section:
      WantedBy: multi-user.target
  - name: sleep.target
    Unit_section:
      Wants:
        - [email protected]
        - [email protected]
        - [email protected]
    Install_section:
      WantedBy: multi-user.target

The same variable can be written in snake_case.

systemd_units:
  - name: [email protected]
    unit_section:
      description: Sleep for %i seconds
      part_of: sleep.target
    service_section:
      restart: always
      exec_start: /bin/sleep %i
    install_section:
      wanted_by: multi-user.target
  - name: sleep.target
    unit_section:
      wants:
        - [email protected]
        - [email protected]
        - [email protected]
    install_section:
      wanted_by: multi-user.target

To organize your code, your may split units into categories.

systemd_services: []
systemd_targets: []
systemd_sockets: []
systemd_units: "{{ systemd_services + systemd_targets + systemd_sockets }}"

Or you may group them by functionality.

systemd_nginx_units: []
systemd_queue_units: []
systemd_php_units: []
systemd_units: "{{ systemd_nginx_units + systemd_queue_units + systemd_php_units }}"

License

MIT