Master Advanced kubectl Tricks: Debug, Filter, and Automate Kubernetes Pods

Print current API used

# kubectl interacts with the ApiServer; the following command prints the API calls
# Useful for debugging API interfaces.
kubectl get ns -v=9

Filter containers by status and delete

kubectl get pods --all-namespaces --field-selector status.phase=Pending -o json \
  | jq '.items[] | "kubectl delete pods \(.metadata.name) -n \(.metadata.namespace)"' \
  | xargs -n 1 bash -c

# Example for running pods
kubectl get pods --all-namespaces --field-selector status.phase=Running -o json \
  | jq '.items[] | "kubectl get pods \(.metadata.name) -o wide -n \(.metadata.namespace)"'

# Delete completed pods in a single namespace
kubectl -n default get pods | grep Completed | awk '{print $1}' | xargs kubectl -n default delete pods

List all pods on a specific node

# Use a field selector to show pods scheduled on a given node
kubectl get pods --all-namespaces -o wide --field-selector spec.nodeName=pve-node1

Count pod distribution across nodes

kubectl -n default get pods -o wide -l app="nginx" | awk '{print $7}' \
  | awk '{ count[$0]++ }
    END {
      printf("%-35s: %s
","Word","Count");
      for (node in count) {
        printf("%-35s: %d
",node,count[node]);
      }
    }'

# Sample output
Word                               : Count
NODE                               : 1
pve-node1                          : 1
pve-node2                          : 1

Using kubectl proxy

You can run a local proxy that forwards requests to the Kubernetes API server, allowing you to call the API without authentication. After starting the proxy, you can inspect raw API traffic, which is handy for debugging dashboard code or other components.

# Start a proxy on port 8080
KUBECONFIG=~/.kube/config-symv3 kubectl proxy -p 8080
kubectl get ns

# Default proxy restrictions (e.g., exec is blocked)
# --accept-hosts='^localhost$,^127\.0\.0\.1$,^\[::1\]$'
# --reject-paths='^/api/.*/pods/.*/exec,^/api/.*/pods/.*/attach'

# Remove reject‑paths to allow exec via the proxy
kubectl proxy -p 8080 --keepalive 3600s --reject-paths='' -v=9

Conclusion

kubectl is a powerful command‑line tool; the commands above illustrate a few advanced usages discovered during daily work. You don’t need to memorize every flag, but knowing that these capabilities exist can save time when you face ad‑hoc operational needs, without having to dive into the client‑API code.