Tasks that run when changed should likely be handlers ANS-E5003
Anti-pattern
Minor
If a task has a when: result.changed setting, it is effectively acting as a handler.
Sometimes you want a task to run only when a change is made on a machine. For example, you may want to restart a service if a task updates the configuration of that service, but not if the configuration is unchanged. Ansible uses handlers to address this use case. Handlers are tasks that only run when notified. Each handler should have a globally unique name.
Bad practice
- name: Template configuration file
ansible.builtin.template:
src: template.j2
dest: /etc/foo.conf
register: copyTemplate
- name: Restart memcached
ansible.builtin.service:
name: memcached
state: restarted
when: copyTemplate.changed
- name: Restart apache
ansible.builtin.service:
name: apache
state: restarted
when: copyTemplate.changed
Recommended
- name: Template configuration file
ansible.builtin.template:
src: template.j2
dest: /etc/foo.conf
notify:
- Restart memcached
- Restart apache
handlers:
- name: Restart memcached
ansible.builtin.service:
name: memcached
state: restarted
- name: Restart apache
ansible.builtin.service:
name: apache
state: restarted
References
[1] [Ansible documentation](https://docs.ansible.com/ansible/latest/userguide/playbookshandlers.html).