Is there any option in Ansible systemd module to print details of Cgroup?

Question

Is there any option in Ansible systemd module to print details of Cgroup?

Below snippet does not print any Cgroup details of particular service.

- name: service
  systemd:
     name: test.service
  register: service_status

- name: print
  debug:
    msg: "{{ service_status.status.ControlGroup }}"

Above code will print only below output

msg: /system.slice/test.service

whereby CLI command

sudo systemctl status test.service 

would print below Cgroup PID details

Cgroup: /system.slice/test.service
        1000 processname1
        1002 processname2
        1003 processname3

Answer 1

Ansible is mainly a Configuration Management tool with which you declare a Desired State. By using a service module (to) Manage services like systemd module (to) Manage systemd units you can make sure that a service is in a certain state.

Even it seems to be possible to gather the service state by using (annot.: not using service_facts module – Return service state information as fact data).

---
- hosts: localhost
  become: true
  gather_facts: false

  tasks:

  - name: Get current service state
    systemd:
      name: "{{ SERVICE_NAME }}"
    register: result

  - name: Show result
    debug:
      msg: "{{ result }}"

it will result in to the output of

...
      ControlPID: '0'
      ExecMainPID: '123'
...
      MainPID: '123'
...

and the main PID only.

Looking into the Source Code of the module systemd.py this for intension

def parse_systemctl_show(lines):
    # The output of 'systemctl show' can contain values that span multiple lines. At first glance it
...
    # part of that value. Cryptically, this would lead to Ansible reporting that the service file
    # couldn't be found.
    #
    # To avoid this issue, the following code only accepts multi-line values for keys whose names
    # start with Exec (e.g., ExecStart=), since these are the only keys whose values are known to
    # span multiple lines.
...

For monitoring a service or processes and sub-processes you may use an other approach or provide more details and information regarding your use case and what you try to achieve.

You may also have a look into pids module – Retrieves process IDs list if the process is running otherwise return empty list and

  - name: Get current service PIDs
    pids:
      name: "{{ SERVICE_NAME }}"
    register: result

  - name: Show result
    debug:
      msg: "{{ result.pids }}"

which would result into an additional output of

TASK [Show result] ******
ok: [localhost] =>
  msg:
  - 124

and the sub-processes of the example service here.