title: Liveness probe for long running PHP CLI job
body: <p>we have a batch data processing script inside a container and want to check it is alive and actually working or whether it should be restarted.</p>
  <p>It is PHP command line script and doesn't expose any kind of server. Currently running in Docker soon in Kubernetes.</p>
  <p>How can we monitor liveness of such script without introducing unnecessary features/libraries?</p>