Ansible task to confirm if a process is running

Ansible 2.1

In the playbook, I started a process:

- name: Start Automation Agent, and enable start on boot service: name=mongodb-mms-automation-agent state=started enabled=yes

From play recap, it appears the process has successfully started.

TASK [install : Start automation agent, and enable start on boot] **************
changed: [server1]

However, when log in to remote host and do a ps, the process is not running. Checking on process log it had failed some pre-requisite (intended).

How do I write a task in a playbook to confirm the process has successfully started?

2 Answers

You can check with the failed Jinja2 filter after running your command that checks if the process is running.

Here is an example that uses the output of the command systemctl status apache2 to decide if Apache is running:

- name: Check if Apache is running command: systemctl status apache2 ignore_errors: yes changed_when: false register: service_apache_status
- name: Report status of Apache fail: msg: | Service apache2 is not running. Output of `systemctl status apache2`: {{ service_apache_status.stdout }} {{ service_apache_status.stderr }} when: service_apache_status | failed

If the command of the first task failed, the second task will fail and show why the first task failed.
The return code is stored in service_apache_status.rc.

Example output of a failure:

TASK: [Check if Apache is running] ***********************
failed: [localhost] => {"changed": false, "cmd": ["systemctl", "status", "apache2"], "delta": "0:00:00.009379", "end": "2016-06-06 15:17:27.827172", "rc": 3, "start": "2016-06-06 15:17:27.817793", "stdout_lines": ["* apache2.service", " Loaded: not-found (Reason: No such file or directory)", " Active: inactive (dead)"], "warnings": []}
stdout: * apache2.service Loaded: not-found (Reason: No such file or directory) Active: inactive (dead)
...ignoring
TASK: [Report status of Apache] ***************************
failed: [localhost] => {"failed": true}
msg: apache2 is not running
systemctl status apache2 output:
* apache2.service Loaded: not-found (Reason: No such file or directory) Active: inactive (dead)

Here is different (albeit possibly less reliable) way, using pgrep, to check if the process is running:

- name: Check if Apache is running shell: pgrep apache2 ignore_errors: yes changed_when: false register: service_apache_status
- name: Report status of Apache fail: msg: | Service apache2 is not running. Return code from `pgrep`: {{ service_apache_status.rc }} when: service_apache_status.rc != 0

This is what I do now:

- name: Confirm Automation Agent is running command: service mongodb-mms-automation-agent status register: agent_status failed_when: "'NOT' in agent_status.stdout" changed_when: False

failed_when is introduced in 1.4. changed_when: False is used to suppress change status. Read more.