ERROR Swarm pid_file _tmp_castor.pid.0 refers to the wrong process name

QUESTION: What causes this error?

ANSWER: This error means that the Swarm Python process started and then exited immediately. The watchdog was told the PID of the Swarm process by the castor_server script and the process was already gone when the watchdog attempted to validate the name of the process. Reboot the node. If this happens again, collect logs and report the incident to DataCore Support.