Liveness Probes

The heartbeat loop updates livenessFile at each worker heartbeat. A probe can check this file without a database query. The default file is arbiter-worker-<workerId> in the system temporary directory.

Configure the probe to fail when the file is stale:

livenessProbe:
  exec:
    command: ["sh", "-c", "find ${TMPDIR:-/tmp}/arbiter-worker-* -mmin -5 | grep -q ."]
  initialDelaySeconds: 30
  periodSeconds: 60

find exits with status 0 when no file matches -mmin. Therefore, a command that uses only find passes when the heartbeat is stale. The grep -q . command makes the probe fail when no current heartbeat file exists. The pool removes the file after a normal shutdown.

The REST API provides two other checks. GET health is a readiness check that queries the database. GET health/live is a liveness check that does not query the database. See REST API and Admin UI.