SAP Containers & Kubernetes interview questions

Almost always a finalizer, and the fast fix is the one that loses data. The safe answer explains what the finalizer is protecting against before removing it.

The scheduler is behaving correctly, which is the part that confuses people. It optimises placement at admission time and never revisits, so a cluster drifts out of balance by design.

Both solve the same surface problem and they disagree about how. The answer that scores names what each one makes hard, and notices that the GitOps tool you use changes the calculus.

A specific configuration trap with a clean explanation. Both controllers act on the same signal from opposite directions, and the result oscillates.

Rootless is the rare security control with a visible invoice. Candidates who can name what it costs, not just what it buys, are the ones who have actually migrated a build farm.

Provisioning is a four-actor handshake between the PV controller, a sidecar, a driver and a backend. Knowing who calls whom turns every stuck PVC from mystery into checklist.

Yes, the proxy moves: one L4 agent per node, eBPF in-kernel, waypoints only where L7 policy demands. The scored answer quantifies the sidecar bill, compares where each architecture lands the proxy, and names migration risks.

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.

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.

Asked in nearly every senior Kubernetes loop, and most candidates answer with a feature list. The scoring answer names the three problems it solves and then argues for not adopting it.

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.

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

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.

The question that finds out whether you know Kubernetes networking or just use it. The model has three rules and everything about CNI follows from them.

A practical question with a precise answer, and the size is not the real cost. Pull time on every node, registry storage, and attack surface all scale with it.

Cilium became the default CNI on major managed platforms for a reason that is mechanical rather than fashionable. The iptables datapath degrades with service count, and eBPF replaces a linear scan with a map lookup.

Default-deny egress breaks name resolution before it breaks anything else, and every connection times out confusingly. The practitioners are the ones who test with positive AND negative probes and know their CNI's fine print.

PDB governs voluntary disruptions only and does not gate rolling updates at all. Candidates who say 'it keeps N pods alive' have just described the part it does not do.

The senior tells are level-triggered reconciliation and finalizer semantics. The partition question separates people who have written a controller from people who have installed one.

The friendliest DaemonSet question there is, and it still separates people who have operated one from people who have read about one. The scheduling rules hide the traps.

Init containers are the easy half. The hard half is why plain sidecars race your app at both ends of the pod's life, and what restartPolicy Always changes about that.

Three propagation mechanisms live inside this one question and only one of them is automatic. Most candidates promise instant reloads; the kubelet has never promised that to anyone.

Namespaces partition resources, not trust. This question finds the people who know which sysctls are namespaced, which ones change every tenant at once, and when only a second kernel will do.