Ansible Role: Systemd

Ansible Role that installs and sets up Systemd units, which are system components and services managed by the systemd service manager in Linux.

Supported Platforms:

• Debian
• Redhat (CentOS/Fedora)
• Ubuntu

Requirements

The systemd tool is standard for most Linux distributions and should be included with most OS installations. Note that systemd requires Linux kernel version 3.13 or higher, and kernel version 4.2 or higher for unified cgroup hierarchy support.

Role Variables

Variables are organized by three stages of software & machine setup:

• Install
• Config
• Launch

Install

• path: (default: /etc/systemd/system)
  • The directory where systemd unit configuration files are loaded from. Files in /etc take priority over those in /run, which in turn take priority over /usr/lib.

Example

unit_config:
  - name: apache
    path: /run/systemd/system
    Service:
      ExecStart: /usr/sbin/httpd
      ExecReload: /usr/sbin/httpd $OPTIONS -k graceful
    Install:
      WantedBy: multi-user.target

• type: (default: service)
  • Defines the type of systemd unit to configure, like a service, socket, or mount.

Example

unit_config:
  - name: apache
    type: socket
    Socket:
      ListenStream: 0.0.0.0:8080
      Accept: yes
    Install:
      WantedBy: sockets.target

Config

Configuration settings are defined in an INI-style config file. Each systemd unit has common sections like Unit and Install, plus one specific to the unit type.

Example for Service

unit_config:
  - name: example-service
    Unit:
      Description: Sleepy service
    Service:
      ExecStart: /usr/bin/sleep infinity
    Install:
      WantedBy: multi-user.target

Launch

• enabled: (default: no)

  • Specifies if the service should start on boot.

• state: (default: stopped)

  • Defines the activation state of the unit.

Dependencies

None

Example Playbook

Example using the role with no specific unit configurations:

- hosts: all
  roles:
  - role: 0x0I.systemd

Example configuring a service, socket, and mount:

- hosts: webservers
  roles:
  - role: 0x0I.systemd
    vars:
      unit_config:
      - name: "my-service"
        Unit:
          After: network-online.target
          Wants: network-online.target
          Requires: my-service.socket
        Service:
          User: 'web'
          Group: 'web'
          ExecStart: '/usr/local/bin/my_service $ARGS'
          ExecReload: '/bin/kill -s HUP $MAINPID'
        Install:
          WantedBy: 'multi-user.target'
      - name: "my-service"
        type: "socket"
        Socket:
          ListenStream: '0.0.0.0:4321'
          Accept: 'true'
        Install:
          WantedBy: 'sockets.target'
      - name: "var-data-my_service"
        type: "mount"
        path: "/run/systemd/system"
        Mount:
          What: '/dev/nvme0'
          Where: '/var/data/my_service'
        Install:
          WantedBy: 'multi-user.target'

License

MIT

Author Information

This role was created in 2019 by O1.IO.