Cluster Maintenance Flashcards

What is the purpose of 'kubectl drain' command?

Answer: To safely evict all Pods from a node for maintenance

kubectl drain safely evicts all Pods from a node, cordoning it to prevent new Pod scheduling, allowing maintenance work on the node.

What is etcd backup important for?

Answer: It stores all cluster state and configuration data

etcd contains all cluster configuration, state, and secrets. Regular backups are critical because losing etcd data means losing the entire cluster state.

How do you upgrade a Kubernetes cluster?

Answer: Upgrade control plane first, then worker nodes one at a time

Cluster upgrades follow a specific order: upgrade the control plane components first, then upgrade worker nodes one at a time (rolling upgrade) to maintain availability.

What is a node cordon?

Answer: Marking a node as unschedulable so no new Pods are placed on it

Cordoning marks a node as unschedulable. Existing Pods continue running, but no new Pods will be scheduled on the cordoned node.

What is the purpose of a Kubernetes health check (probe)?

Answer: To determine if a container is running correctly and ready to serve traffic

Health probes (liveness, readiness, startup) let Kubernetes know if a container is alive, ready for traffic, or still starting up, enabling automatic recovery.

What happens when a liveness probe fails?

Answer: Kubernetes restarts the container

When a liveness probe fails, Kubernetes determines the container is unhealthy and restarts it, following the Pod's restart policy.