Scheduling, controllers and reconciliation, services and ingress, probes, and resource management.
5 questions in DevOps & Cloud.
Kubernetes CrashLoopBackOff debugging starts with the previous container logs, exit code and pod events. Then separate application crashes from liveness probe kills, bad configuration, missing dependencies and OOMKilled restarts.
CPU is compressible, so the kubelet throttles it rather than evicting for it. Eviction comes from memory, ephemeral storage or inodes - and which pods die is decided by QoS class, not by who caused the pressure. Check node conditions and eviction thresholds first, then fix the requests and limits so critical workloads are Guaranteed rather than BestEffort.
Removing a pod from its EndpointSlice and sending it SIGTERM happen concurrently, and the data-plane update takes time to propagate, so requests keep arriving at a pod that has already begun shutting down. The fix is a preStop delay plus an application that finishes in-flight work before exiting.
eBPF-based Kubernetes network policy can enforce hard multi-tenancy with faster identity-aware checks than long iptables chains, but it demands verifier-safe rollouts, fail-closed controls, and strong policy observability.
A node image change is a release of the layer underneath Kubernetes, so the control plane cannot stage it, roll it back or reliably report on it. Treat node pools as rings, replace nodes rather than patching them in place, and get the health signal from outside the cluster. It also connects node lifecycle to the point an interviewer is testing.