Ansible & systemctl daemon-reload

(UPDATE: there is now a PR open to add this functionality)

We recently migrated to Debian 8 which, by default, uses systemd. I can appreciate why some people have misgivings about it, but from my point of view it’s been a massive improvement.

Our unit files look like this now:

[Service]
ExecStart=/var/www/{{ app_name }}/app.js
Restart=always
StandardOutput=syslog
StandardError=syslog
SyslogIdentifier={{ app_name }}
User={{ app_name }}
Group={{ app_name }}
Environment=NODE_ENV={{ env }}
WorkingDirectory=/var/www/{{ app_name }}

[Install]
WantedBy=multi-user.target

Compared to a 3 page init script, using start-stop-daemon. And we no longer need a watchdog like monit.

We do our deployments using ansible, which already knows how to play nice with systemd. One thing missing though, is that if you change a unit file you need to call systemctl daemon-reload before the changes will be picked up.

There’s a discussion underway as to whether ansible should take care of it. But for now, the easiest thing to do is add another handler:

- name: Install unit file
  sudo: true
  copy: src=foo.service dest=/lib/systemd/system/ owner=root mode=644
  notify:
    - reload systemd
    - restart foo

with a handler like this:

- name: reload systemd
  sudo: yes
  command: systemctl daemon-reload

UPDATE: if you need to restart the service later in the same play, you can flush the handlers to ensure daemon-reload has been called:

- meta: flush_handlers
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4 thoughts on “Ansible & systemctl daemon-reload

  1. felipe1982 April 12, 2017 / 4:02 am

    Moreover, from what I can tell, the `systemd` ansible module wouldn’t work on a non-systemd system, which makes *this* post all the more relevant.

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