Probe failure and container restart behavior in Kubernetes - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a liveness probe in Kubernetes?

A liveness probe checks if a container is alive. If it fails, Kubernetes restarts the container to fix it.

beginner

What happens when a readiness probe fails?

When a readiness probe fails, Kubernetes stops sending traffic to the container but does not restart it.

intermediate

How does Kubernetes decide to restart a container after a probe failure?

Kubernetes restarts a container only if the liveness probe fails. Readiness probe failures do not cause restarts.

intermediate

What is the difference between a startup probe and a liveness probe?

A startup probe checks if the container application has started. It prevents premature liveness probe failures during startup.

beginner

Why is it important to configure probes correctly in Kubernetes?

Correct probe configuration ensures containers restart only when needed and traffic is routed properly, improving app reliability.

What does a failing liveness probe cause in Kubernetes?

A Container restart

B Stop sending traffic to container

C Pod deletion

D No action

A failing liveness probe triggers Kubernetes to restart the container to fix the issue.

If a readiness probe fails, what happens?

A Traffic stops going to the container

B Container restarts immediately

C Pod is deleted

D Nothing happens

A failing readiness probe causes Kubernetes to stop sending traffic to the container but does not restart it.

Which probe helps avoid restarting a container too early during startup?

A Readiness probe

B Startup probe

C Liveness probe

D Health probe

The startup probe checks if the container has started properly before liveness probes begin.

What is the main purpose of a readiness probe?

A Restart container if unhealthy

B Delete pod if failing

C Monitor CPU usage

D Check if container is ready to serve traffic

Readiness probes check if a container is ready to accept traffic without restarting it.

What happens if all probes are misconfigured?

A No effect on container behavior

B Kubernetes ignores probes

C Containers restart unnecessarily or traffic is misrouted

D Pods scale automatically

Misconfigured probes can cause unnecessary restarts or improper traffic routing, harming app stability.

Explain how Kubernetes uses liveness and readiness probes to manage container health and traffic.

Think about what happens when each probe fails.

Describe the role of a startup probe and why it is useful in Kubernetes container management.

Consider container startup delays and probe timing.