Container Orchestration Flashcards

Which Kubernetes object should you use to expose a set of Pods as a network service with a stable IP and DNS name?

Answer: Service

A Service provides a stable virtual IP and DNS name that load-balances traffic across a set of Pods matching its selector.

What is the effect of setting `terminationGracePeriodSeconds: 0` on a Pod?

Answer: The Pod is immediately killed with no grace period

Setting this to 0 causes the Pod to be force-killed immediately without allowing containers to handle SIGTERM.

In Kubernetes, what is the purpose of a Namespace?

Answer: Partitions cluster resources between multiple users or teams

Namespaces provide a mechanism to divide cluster resources between multiple users, teams, or projects with logical isolation.

What is the primary difference between `kubectl apply` and `kubectl create`?

Answer: `apply` is declarative and updates existing resources; `create` fails if the resource already exists

`kubectl apply` is declarative and merges changes into existing resources, while `kubectl create` returns an error if the resource already exists.

Which container runtime interface does Kubernetes use to communicate with container runtimes like containerd or CRI-O?

Answer: Container Runtime Interface (CRI)

The Container Runtime Interface (CRI) is the API that kubelet uses to interact with compatible container runtimes.

A Pod is stuck in `Pending` state. What is the most likely cause?

Answer: No node satisfies the Pod's scheduling requirements

A Pod remains Pending when the scheduler cannot find a suitable node due to insufficient resources, taints, or affinity rules.

What is the role of the kubelet on a Kubernetes worker node?

Answer: Ensures containers described in PodSpecs are running and healthy

The kubelet is an agent on each node that watches for PodSpecs and ensures the containers are running as expected.