ansible check non-existent service [duplicate] - ansible

Question

I have an Ansible playbook for deploying a Java app as an init.d daemon.
Being a beginner in both Ansible and Linux I'm having trouble to conditionally execute tasks on a host based on the host's status.
Namely I have some hosts having the service already present and running where I want to stop it before doing anything else. And then there might be new hosts, which don't have the service yet. So I can't simply use service: name={{service_name}} state=stopped, because this will fail on new hosts.
How I can I achieve this? Here's what I have so far:
- name: Check if Service Exists
shell: "if chkconfig --list | grep -q my_service; then echo true; else echo false; fi;"
register: service_exists
# This should only execute on hosts where the service is present
- name: Stop Service
service: name={{service_name}} state=stopped
when: service_exists
register: service_stopped
# This too
- name: Remove Old App Folder
command: rm -rf {{app_target_folder}}
when: service_exists
# This should be executed on all hosts, but only after the service has stopped, if it was present
- name: Unpack App Archive
unarchive: src=../target/{{app_tar_name}} dest=/opt

Answer 1

See the service_facts module, new in Ansible 2.5.
- name: Populate service facts
service_facts:
- debug:
msg: Docker installed!
when: "'docker' in services"

Answer 2

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

Answer 3

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

Answer 4

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)

Answer 5

Another approach for systemd (from Jakuje):
- name: Check if cups-browsed service exists
command: systemctl cat cups-browsed
check_mode: no
register: cups_browsed_exists
changed_when: False
failed_when: cups_browsed_exists.rc not in [0, 1]
- name: Stop cups-browsed service
systemd:
name: cups-browsed
state: stopped
when: cups_browsed_exists.rc == 0

Answer 6

Building on #Maciej's answer for RedHat 8, and combining it with the comments made on it.
This is how I managed to stop Celery only if it has already been installed:
- name: Populate service facts
service_facts:
- debug:
msg: httpd installed!
when: ansible_facts.services['httpd.service'] is defined
- name: Stop celery.service
service:
name: celery.service
state: stopped
enabled: true
when: ansible_facts.services['celery.service'] is defined
You can drop the debug statement--it's there just to confirm that ansible_facts is working.

Answer 7

This way using only the service module has worked for us:
- name: Disable *service_name*
service:
name: *service_name*
enabled: no
state: stopped
register: service_command_output
failed_when: >
service_command_output|failed
and 'unrecognized service' not in service_command_output.msg
and 'Could not find the requested service' not in service_command_output.msg

Answer 8

My few cents. The same approach as above but for kubernetes
Check if kublete service is running
- name: "Obtain state of kublet service"
command: systemctl status kubelet.service
register: kubelet_status
failed_when: kubelet_status.rc > 3
Display debug message if kublet service is not running
- debug:
msg: "{{ kubelet_status.stdout }}"
when: "'running' not in kubelet_status.stdout"

Answer 9

You can use the service_facts module since Ansible 2.5. But you need to know that the output are the real name of the service like docker.service or somthing#.service. So you have different options like:
- name: Populate service facts
service_facts:
- debug:
msg: Docker installed!
when: "'docker.service' in services"
Or you can search for the string beginning with the service name; that is much more reliable, because the service names are different between the distributions:
- name: Populate service facts
service_facts:
- debug:
msg: Docker installed!
when: "services.keys()|list|select('search', '^docker')|length >0"