How to get error output when ansible.systemd fails with restart? - error-handling

Question

With the following ansible:
- name: Reload changes in configuration and restart docker service
systemd:
name: docker
enabled: true
daemon_reload: true
state: restarted
register: command_output
- name: Print to console
debug:
msg: "{{command_output.stdout}}"
I see the following error:
fatal: [xxxxxx]: FAILED! => {"changed": false, "msg": "Unable to start
service docker: Job for docker.service failed because the control
process exited with error code.\nSee "systemctl status
docker.service" and "journalctl -xe" for details.\n"}
This is of course a very useful error message when on the command line, but in ansible, not so much. My attempt at capturing the error output and dispalying it in debug has not been very fruitful. So the question is:
How can I get more details about the reason why ansible.systemd failed in this case?
Should I try to invoke journalctl -xe or systemctl status docker.service manually, or is there some other more ansible friendly way?

Answer 1

Whatever ansible module capture is already there stderr or stdout return values.. If you want to get more details of the error, you can try Block and Rescue ... Block and Resuce Documentation
block:
- name: Reload changes in configuration and restart docker service
systemd:
name: docker
enabled: true
daemon_reload: true
state: restarted
register: command_output
- name: Print to console
debug:
msg: "{{command_output.stdout}}"
rescue:
- name: get errors
shell: journalctl -xe # or systemctl status docker.service
register: err_msg
- name: Print error message to console
debug:
msg: "{{ err_msg.stdout }}"