Unfortunately, this scheme is not perfect yet.
Crashing the pid of the postfix service underneath does not raise the alert [1]. As this
does not affect the service's status...
For other types of service (simple, etc...), this is working appropriately though. I
Checked with the journalbeat.service for instance.
[1] That service is of type oneshot. There is no feedback loop between the service and
the command/process triggered. So the status remains unaffected if the process crashes.
Depends on D6124
Related to T3495