Microsoft Containers & Kubernetes interview questions

Service types choose how an application is exposed. Follow the actual traffic path: cloud controllers can target nodes or pods, and internal exposure differs from public exposure.

A Service moves connections and an Ingress reads requests. The gap between those two sentences is hostname routing, path routing and TLS, and it is also why an Ingress object alone does nothing.

Selectors match object labels; owner references record controller relationships. Keeping those mechanisms separate explains how a Service can select the wrong pods without owning them.

It sounds like trivia and screens for something real: whether you understand that a pod is a shared namespace boundary with an owner, not just a group of containers.

SSH plus yum is how outages start. The senior answer replaces nodes from versioned images on a cadence, orchestrates with surge capacity and PDBs, and can explain the kernel-skew problem that makes fleet homogeneity a feature.

Kubelet resource metrics to metrics-server to aggregated API to HPA controller: every hop adds lag and averaging. Walking the path and naming where it distorts demand separates operators from dashboard readers.

Heartbeats, conditions and taints are the only vocabulary the control plane understands. NPD translates journald and kernel ring messages into that vocabulary; custom plugins carry your hardware's dialect.

Kubernetes does not see GPUs, it sees an extended resource that something has to advertise. When that advertisement is missing or wrong, the scheduler is behaving correctly and the node is lying.

A Job with a sidecar was broken by design for years: the workload finishes, the proxy does not, and the pod never terminates. Native sidecars fix it by making the container an init container that keeps running.

Changing pod resources historically required recreation, which made vertical autoscaling disruptive for workloads with expensive recovery. In-place resize changes that, with limits worth knowing.

Ingress solved routing by convention and annotation, which meant every controller invented its own. Gateway API's real contribution is not features, it is splitting one object into three so that platform and application teams stop editing the same file.

Clusters multiply for good reasons: regions, isolation, tenancy, blast radius. The problem is not creating them, it is that cluster seven diverges from cluster three and nobody knows until an upgrade behaves differently.

Route attachment and cross-namespace backend access have different owners. Use route status to find the failing boundary before broadening any permission.

Both run pods, so the answer sounds obvious until an interviewer asks what happens when you delete one. The guarantees are narrower and more specific than most candidates think.

The pair everyone configures and few can explain. QoS hints at eviction risk, but usage versus requests and Pod priority determine node-pressure ranking, and CPU and memory behave completely differently when you exceed them.

A pod is a shared network and storage boundary that happens to contain containers. Once you can say what the containers inside one share, sidecars and init containers stop needing separate explanations.

Follow a Deployment change through the API server, controllers, scheduler and kubelet. Each handoff gives you a different place to investigate when a pod never starts.

The single most common Kubernetes interview question, and the one where a vague answer is most obvious. Every stage you name is a place the interviewer can ask you to debug.

Everyone can recite the three. Explain what each failure causes, and why a badly configured liveness probe is more dangerous than none at all.