03 - Startup Probe.md

Startup Probe

A Probe is a diagnostic performed periodically by the kubelet on a Container.

The kubelet can optionally perform and react to three kinds of probes on running containers. The most common and widely known livenessProbe and redinessProbe.

Startup probes are similar to readiness probes but only executed at startup. They are optimized for slow starting containers or applications. We can configure failureThreshold and periodSeconds

startupProbe:
  httpGet:
    path: /healthz
    port: 8080
  failureThreshold: 40
  periodSeconds: 5

livenessProbe:
  httpGet:
    path: /healthz
    port: 8080
  failureThreshold: 1
  periodSeconds: 10

readinessProbe:
  httpGet:
    path: /ready
    port: 8080
  failureThreshold: 1
  periodSeconds: 10

With this config the application will have a maximum of 200 seconds (40*5) to finish its startup. Once the startup probe has succeeded, the liveness probe takes over.

If the startup probe never succeeds, the container is killed after 200s and subject to the pod's restartPolicy