In our environment we have custom services that need to be stopped and
restarted very gracefully to not interrupt active sessions.
A stop job, depending on the state, can take up to 20 minutes until the
process exits. It simply reacts to SIGTERM with a graceful shutdown.
By default, systemctl blocks until the job has completed, which leads to
Ansible hanging on this task for up to 20 minutes.
Thankfully systemctl supports the `--no-block` flag which lets the job
continue in the background.
This PR adds support for that flag as the `no_block` boolean option.
From the man page:
--no-block
Do not synchronously wait for the requested operation to
finish. If this is not specified, the job will be
verified, enqueued and systemctl will wait until the
unit's start-up is completed. By passing this argument,
it is only verified and enqueued. This option may not be
combined with --wait.