Differences between Liveness and Readness Probes

Liveness Probe

Liveness Probe is used to check if the container is still alive. If the container is not alive, Kubernetes will restart it.

livenessProbe:
  httpGet:
    path: /healthz
    port: 8080
  initialDelaySeconds: 5
  periodSeconds: 10

Readness Probe

Readness Probe is used to check if the container is ready to serve requests. If the container is not ready, Kubernetes will not send requests to it.

readinessProbe:
  httpGet:
    path: /readyz
    port: 8080
  initialDelaySeconds: 10
  periodSeconds: 5

Key Differences Between Liveness and Readiness Probes

Feature	Liveness Probe	Readiness Probe
Purpose	Check if the application is "alive" or stuck.	Check if the application is "ready" to serve traffic.
Action on Failure	Kubernetes will restart the container if the probe fails repeatedly.	Kubernetes stops routing traffic to the container but doesn't restart it.
Use Case	Detect unresponsive applications (e.g., deadlocks, crashes).	Ensure only healthy and ready containers handle traffic.
Restart Behavior	Yes, the container is restarted.	No, the container is not restarted, just temporarily removed from service.
Examples	Application stuck in a deadlock, memory leaks, crashes.	Application loading config files, warming up caches.
Impact on Pod's Traffic	No impact unless the container restarts.	Traffic will stop being routed to the pod if readiness fails.