Kubernetes (kubectl)¶

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kubectl talks to a cluster's API server. Almost every command takes -n <namespace> (or -A for all namespaces) — forgetting it is the number-one reason "my pod isn't there." Set a default namespace to save the typing.

Inspect Resources¶

Command	Shows
`kubectl get pods`	pods in the current namespace
`kubectl get pods -A`	pods across all namespaces
`kubectl get pods -o wide`	add node & IP columns
`kubectl get all`	pods, services, deployments, etc.
`kubectl describe pod <name>`	events + full detail for one object
`kubectl get pod <name> -o yaml`	the live manifest

Context & Namespace¶

Command	Does
`kubectl config get-contexts`	list clusters you can talk to
`kubectl config current-context`	which cluster am I on?
`kubectl config use-context <name>`	switch clusters
`kubectl get pods -n kube-system`	target one namespace
`kubectl config set-context --current --namespace=dev`	set a default namespace

Know your context before you act. The same kubectl delete runs against whatever context is current — including prod. kubectx / kubens (or a shell prompt that shows the context) make the active target impossible to miss.

Apply & Manage¶

Command	Does
`kubectl apply -f app.yaml`	create or update from a manifest
`kubectl delete -f app.yaml`	delete what the manifest defines
`kubectl edit deploy <name>`	edit a live object in $EDITOR
`kubectl scale deploy <name> --replicas=3`	change replica count
`kubectl rollout restart deploy <name>`	restart pods (e.g. after a config change)
`kubectl rollout status deploy <name>`	watch a rollout finish
`kubectl rollout undo deploy <name>`	roll back to the previous version

Debugging¶

Command	Does
`kubectl logs <pod>`	print a pod's logs
`kubectl logs -f <pod>`	follow logs live
`kubectl logs <pod> --previous`	logs from the crashed instance
`kubectl exec -it <pod> -- sh`	shell into a running pod
`kubectl port-forward <pod> 8080:80`	tunnel a local port to the pod
`kubectl get events --sort-by=.lastTimestamp`	recent cluster events

Nodes & Cluster¶

Command	Shows / does
`kubectl get nodes`	cluster nodes and their status
`kubectl top nodes`	live CPU / memory per node (needs metrics-server)
`kubectl top pods`	resource use per pod
`kubectl cluster-info`	control-plane endpoints
`kubectl cordon <node>`	stop scheduling new pods onto a node
`kubectl drain <node>`	evict pods to prep a node for maintenance