Check if service exists with Ansible

See the service_facts module, new in Ansible 2.5.

- name: Populate service facts
  service_facts:
- debug:
    msg: Docker installed!
  when: "'docker' in services"

Of course I could also just check if the wrapper script exists in /etc/init.d. So this is what I ended up with:

  - name: Check if Service Exists
    stat: path=/etc/init.d/{{service_name}}
    register: service_status

  - name: Stop Service
    service: name={{service_name}} state=stopped
    when: service_status.stat.exists
    register: service_stopped

It would be nice if the "service" module could handle "unrecognized service" errors.

This is my approach, using the service command instead of checking for an init script:

- name: check for apache
  shell: "service apache2 status"
  register: _svc_apache
  failed_when: >
    _svc_apache.rc != 0 and ("unrecognized service" not in _svc_apache.stderr)

- name: disable apache
  service: name=apache2 state=stopped enabled=no
  when: "_svc_apache.rc == 0"

• check the exit code of "service status" and accept the exit code 0 when the output contains "unrecognized service"
• if the exit code was 0, that service is installed (stopped or running)

I modified Florian's answer to only use the return code of the service command (this worked on Mint 18.2)

- name: Check if Logstash service exist
  shell: service logstash status 
  register: logstash_status
  failed_when: not(logstash_status.rc == 3 or logstash_status.rc == 0)

- name: Check if Logstash service exist
  service:
    name: logstash
    state: stopped 
  when: logstash_status.rc == 0