In-cluster DNS resolution test

Resolve a Service FQDN from an ephemeral pod to isolate CoreDNS vs app DNS issues

kubectl run dnstest --rm -it --image=nicolaka/netshoot --restart=Never -- dig +short <name>.<ns>.svc.cluster.local
tool
k8s-debug27 commands
tags
k8s-debugdnsnetworktroubleshooting

More k8s-debug commands

  • Ordered events for a pod
    kubectl events --for pod/<pod> -n <ns> --types=Warning

    Stream only Warning events scoped to one pod in chronological order; modern: replaces get events filter

  • Previous crash logs with timestamps
    kubectl logs <pod> -n <ns> -c <name> --previous --timestamps --tail=200

    Tail the crashed container's prior instance logs to catch the pre-restart stack trace

  • Ephemeral debug container
    kubectl debug -it <pod> --image=nicolaka/netshoot -n <ns>

    Attach a debug container (netshoot) to a running pod — shares PID/net namespaces

  • Node resource usage
    kubectl top nodes

    CPU and memory per node (requires metrics-server)

  • Pod resource usage sorted
    kubectl top pods -A --sort-by=memory

    Memory-sorted pod usage across all namespaces — find the hungry ones

all 27 k8s-debug commands