tell 'service' module to continue with playbook, if service isn't found

[dulh...@mailbox.org]

I am trying to install postgresql via a playbook and want to make sure the service is not running prior installation on the target (rhel7/8 & debian10) machines.

However my task below

    - name: stop postgresql.service from systemd if running
      service:
        name: postgresql.service
        state: stopped
        # enabled: false
      become: yes

is failing ('Could not find the requested service postgresql.service: host')

so, I guess I have to build something that directs the target to ignore that and continues with the playbook. I just can't see anything

[Stefan Hornburg (Racke)]

You can check the status of the postgresql service as follows:

- service_facts:

- debug:
msg: "{{ ansible_facts.services.postgresql | default({ 'state' : 'absent'}) }}"

TASK [service_facts] ***************************************************************************************************************************************
ok: [papas]

TASK [debug] ***********************************************************************************************************************************************
ok: [papas] => {
"msg": {
"name": "postgresql",
"source": "sysv",
"state": "running"
}
}

Regards
Racke

>
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--
Ecommerce and Linux consulting + Perl and web application programming.
Debian and Sympa administration.

[dulh...@mailbox.org]

> On 10/15/2021 11:41 AM Stefan Hornburg (Racke) <ra...@linuxia.de> wrote:
>
>
> On 15/10/2021 11:20, dulhaver via Ansible Project wrote:
> >
> > I am trying to install postgresql via a playbook and want to make sure the service is not running prior installation on the target (rhel7/8 & debian10) machines.
> >
> > However my task below
> >
> >     - name: stop postgresql.service from systemd if running
> >       service:
> >         name: postgresql.service
> >         state: stopped
> >         # enabled: false
> >       become: yes
> >
> > is failing ('Could not find the requested service postgresql.service: host')
> >
> > so, I guess I have to build something that directs the target to ignore that and continues with the playbook. I just can't see anything
>
> You can check the status of the postgresql service as follows:
>
> - service_facts:
>
> - debug:
> msg: "{{ ansible_facts.services.postgresql | default({ 'state' : 'absent'}) }}"
>
> TASK [service_facts] ***************************************************************************************************************************************
> ok: [papas]
>
> TASK [debug] ***********************************************************************************************************************************************
> ok: [papas] => {
> "msg": {
> "name": "postgresql",
> "source": "sysv",
> "state": "running"
> }
> }

are those arguments to the the "service" module? how exaclty would I weave those into my task? I tried

- name: stop postgresql.service from systemd if running
service:
name: postgresql

service_facts:

debug:
msg: "{{ ansible_facts.services.postgresql | default({ 'state' : 'absent'}) }}"

state: stopped
# enabled: false
become: yes

but that did not work

[Stefan Hornburg (Racke)]

No, use my tasks verbatim.

Regards
Racke

[dulh...@mailbox.org]

hm ... pasting this verbatim to my plabook does not survice a --symtax-check

I figured out soome sort of sense-making output with adding 2 tasks based on what you posted.

############################################################
- name: gather service facts
service_facts:

- name: return postgres running or not

debug:
msg: "{{ ansible_facts.services.postgresql | default({ 'state' : 'absent'}) }}"

############################################################

however ... what do I do whith that output ('state: absent' in my test scenario)?

Maybe I need to put this to work as some sort of condition deciding whether to run a 'service' task disabling the postgresql.service or not?

[Stefan Hornburg (Racke)]

What is the diagnosis of the syntax check?

>
> I figured out soome sort of sense-making output with adding 2 tasks based on what you posted.
>
> ############################################################
> - name: gather service facts
> service_facts:
>
> - name: return postgres running or not
> debug:
> msg: "{{ ansible_facts.services.postgresql | default({ 'state' : 'absent'}) }}"
> ############################################################
>
> however ... what do I do whith that output ('state: absent' in my test scenario)?
>
> Maybe I need to put this to work as some sort of condition deciding whether to run a 'service' task disabling the postgresql.service or not?
>

Correct. For example:

when: ansible_facts.services.postgresql.state == 'running'

[dulh...@mailbox.org]

######################################################################
play -v --limit [host] postgres_install.yml --syntax-check
Using /path/to/ansible.cfg as config file
ERROR! We were unable to read either as JSON nor YAML, these are the errors we got from each:
JSON: Expecting value: line 1 column 1 (char 0)

Syntax Error while loading YAML.
did not find expected key

The error appears to be in '/home/gwagner/repos/ansible/step/step_server_env/postgres_install_test_external.yml': line 130, column 4, but may
be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:
- service_facts:
^ here
######################################################################

> > I figured out soome sort of sense-making output with adding 2 tasks based on what you posted.
> >
> > ############################################################
> > - name: gather service facts
> > service_facts:
> >
> > - name: return postgres running or not
> > debug:
> > msg: "{{ ansible_facts.services.postgresql | default({ 'state' : 'absent'}) }}"
> > ############################################################
> >
> > however ... what do I do whith that output ('state: absent' in my test scenario)?
> >
> > Maybe I need to put this to work as some sort of condition deciding whether to run a 'service' task disabling the postgresql.service or not?
> >
>
> Correct. For example:
>
> when: ansible_facts.services.postgresql.state == 'running'

ok, thx. I'll play with that

[Stefan Hornburg (Racke)]

Could be an indentation problem.

Regards
Racke

>
>
>>> I figured out soome sort of sense-making output with adding 2 tasks based on what you posted.
>>>
>>> ############################################################
>>> - name: gather service facts
>>> service_facts:
>>>
>>> - name: return postgres running or not
>>> debug:
>>> msg: "{{ ansible_facts.services.postgresql | default({ 'state' : 'absent'}) }}"
>>> ############################################################
>>>
>>> however ... what do I do whith that output ('state: absent' in my test scenario)?
>>>
>>> Maybe I need to put this to work as some sort of condition deciding whether to run a 'service' task disabling the postgresql.service or not?
>>>
>>
>> Correct. For example:
>>
>> when: ansible_facts.services.postgresql.state == 'running'
>
> ok, thx. I'll play with that
>

[dulh...@mailbox.org]

I am still stuck with this:

theses 3 TASKS should take care of checking the status of postgresql.server and (if running) stop it
####################################################################################################

- name: gather service facts
service_facts:

- name: return postgres running or not
debug:
msg: "{{ ansible_facts.services.postgresql | default({ 'state' : 'absent'}) }}"

- name: stop postgresql.service from systemd if running
service:
name: postgresql

state: stopped
when: ansible_facts.services.postgresql.state == 'running'
become: yes
####################################################################################################

however I am getting an 'Unsupported parameters for (systemd) module: when Supported parameters include: daemon_reexec, daemon_reload, enabled, force, masked, name, no_block, scope, state, user' error upon that last TASK

as 'state' is mentioned as supported paramter I am wondering whether the wording 'running' / 'present' .... may be the root cause of my problem.

thec check for running services shows 'running', 'stopped', 'disabled' as far as I can see, where the state in the service task would be 'started' as far as I can tell.

can anybody advise on this?

[Stefan Hornburg (Racke)]

"when" is a task level parameter and not a module parameter, so please shift it to the left on the same level as "become".

Regards
Racke

>
> however I am getting an 'Unsupported parameters for (systemd) module: when Supported parameters include: daemon_reexec, daemon_reload, enabled, force, masked, name, no_block, scope, state, user' error upon that last TASK
>
> as 'state' is mentioned as supported paramter I am wondering whether the wording 'running' / 'present' .... may be the root cause of my problem.
>
> thec check for running services shows 'running', 'stopped', 'disabled' as far as I can see, where the state in the service task would be 'started' as far as I can tell.
>
> can anybody advise on this?
>

[Brian Coca]

A simple solution is to 'alter' the failure condition:

- name: stop postgresql.service from systemd if running
service:
name: postgresql.service
state: stopped

become: yes
register: psql_result
failed_when: psql_result is failed and 'Could not find the
requested service postgresql.service' not in psql_result['msg']

Now it will only fail for reasons that are not 'the service is missing'

----------
Brian Coca

[dulh...@mailbox.org]

it took a bit of fiddeling with the indentation (not being transalted nicely to the website view of the mailing list) but finally this combination works (in terms of not producing any error on running the playbook).

##########################################################################

- name: gather service facts
service_facts:

- name: return postgres running or not
debug:
msg: "{{ ansible_facts.services.postgresql | default({ 'state' : 'absent'}) }}"

- name: stop postgresql.service from systemd if running
service:
name: postgresql.service
state: stopped
become: yes
register: psql_result

failed_when: psql_result is failed and 'Could not find the requested service postgresql..service' not in psql_result['msg']
##########################################################################

I have not finish the entire installation, so I can not yet say whether in works on the entire context yet.

nevertheless tx all of you for the suggestions

[Vladimir Botka]

On Sun, 17 Oct 2021 17:27:23 +0200 (CEST)

dulhaver via Ansible Project <ansible...@googlegroups.com> wrote:

> - name: gather service facts
> service_facts:

> ...

> - name: stop postgresql.service from systemd if running
> service:
> name: postgresql.service
> state: stopped
> become: yes
> register: psql_result
> failed_when: psql_result is failed and 'Could not find the requested service postgresql..service' not in psql_result['msg']

Testing service existence should be simpler, I think

- service_facts:
- service:
name: postgresql.service
state: stopped
become: true
register: psql_result
when: "'postgresql.service' in services"


--
Vladimir Botka