Essential kubectl Commands for DevOps Engineers

Get kubectl version

Check the client and server versions of the kubectl tool.

kubectl version

Get cluster information

Retrieve detailed information about the Kubernetes cluster.

kubectl cluster-info

List available Kubernetes API resources

List all top‑level API resources that the API server makes available.

kubectl api-resources

Retrieve Kubernetes contexts

List all contexts (clusters, users, namespaces) defined in the kubeconfig file.

kubectl config get-contexts

Switch clusters

Switch between different contexts/clusters, useful for managing multiple environments.

kubectl config use-context <context_name>

Set default namespace for a context

Set or change the default namespace used by kubectl for a given context.

kubectl config set-context --current --namespace <NAMESPACE_NAME>

Create or update resources with kubectl

Create or update Kubernetes resources to match the desired state defined in a YAML file.

kubectl apply -f <file_path>

Create resources with kubectl

Create a new resource, e.g., a namespace.

kubectl create namespace <namespace_name>

Patch Kubernetes resources

Modify resource attributes using merge, JSON merge, or JSON patch formats (JSON and YAML are accepted). Custom resources do not support merge patches.

kubectl patch (-f FILENAME | TYPE NAME) [-p PATCH|--patch-file FILE]

Examples:

# Update node JSON
kubectl patch node k8s-node-1 -p '{"spec":{"unschedulable":true}}'

# Update node YAML
kubectl patch node k8s-node-1 -p $'spec:\n  unschedulable: true'

# Strategic merge patch on a node
kubectl patch -f node.json -p '{"spec":{"unschedulable":true}}'

# Patch container image (merge key required)
kubectl patch pod valid-pod -p '{"spec":{"containers":[{"name":"kubernetes-serve-hostname","image":"new image"}]}}'

# JSON patch to update container image
kubectl patch pod valid-pod --type='json' -p='[{"op": "replace", "path": "/spec/containers/0/image", "value":"new image"}]'

# Merge patch to scale a deployment
kubectl patch deployment nginx-deployment --subresource='scale' --type='merge' -p '{"spec":{"replicas":2}}'

List any resources

List all deployments in the current namespace.

kubectl get deploy -n kube-system

Manage deployments

Manage rollout and updates of deployments.

kubectl rollout status deployment/<deployment_name>

Describe pod information

Get detailed information about a specific pod.

kubectl describe pod <pod_name> -n <NAMESPACE>

View container logs

Retrieve logs from a running container inside a pod.

kubectl logs <pod_name> <container_name> -f

Execute commands in a pod

Run a command directly inside a container of a pod.

kubectl exec -it <pod_name> -c <container_name> -- /bin/sh

Scale replicas

Scale the number of replicas for a Deployment, ReplicationController, or StatefulSet.

kubectl scale deployment <deployment_name> --replicas=3

Expose Kubernetes resources

Expose a Deployment, ReplicaSet, or Pod as a Service; example uses a NodePort service.

kubectl expose deployment <deployment_name> --type=NodePort --port=<port_number>

Delete Kubernetes resources

Delete resources defined in a YAML file or delete them directly by name.

kubectl delete pod <pod_name>

Taint nodes in Kubernetes

Add a taint to a node to restrict pod scheduling unless the pod tolerates the taint.

kubectl taint nodes <node_name> key=value:taint_effect

Mark nodes as unschedulable

Mark a node as unschedulable (cordon) or make it schedulable again (uncordon).

kubectl cordon NODE
kubectl uncordon NODE

Drain Kubernetes nodes

Evacuate a node, optionally forcing the operation or specifying a grace period.

# Drain node "foo" even if pods are not managed by a controller
kubectl drain foo --force

# Drain with a 15‑minute grace period
kubectl drain foo --grace-period=900

Explain resources

Get documentation for a resource’s schema.

kubectl explain pods

List events

List cluster events sorted by creation timestamp.

kubectl get events --sort-by=.metadata.creationTimestamp

Diff resource configuration

Compare the live cluster state with the state defined in a manifest.

kubectl diff -f ./my-manifest.yaml

Set configuration resources

Perform a rolling update of a deployment’s container image.

kubectl set image deployment/frontend www=image:v2

Replace resources in Kubernetes

Force replace a resource (delete then recreate), which may cause service interruption.

kubectl replace --force -f ./pod.json

Manage labels

Add, delete, or overwrite labels on resources.

kubectl label pods my-pod new-label=awesome   # add
kubectl label pods my-pod new-label-          # delete
kubectl label pods my-pod new-label=new-value --overwrite   # overwrite

Edit resources

Edit any API resource using the default editor or a specified one.

kubectl edit svc/docker-registry
KUBE_EDITOR="nano" kubectl edit svc/docker-registry

Debug resources

Create an interactive debugging pod attached to an existing pod or node.

kubectl debug my-pod -it --image=busybox:1.28
kubectl debug node/my-node -it --image=busybox:1.28

Run a pod

Launch a single‑instance container or a set of containers.

kubectl run -i --tty busybox --image=busybox:1.28   # interactive shell

Copy files/directories to/from containers

Copy files between the local machine and a pod.

kubectl cp /tmp/foo_dir my-pod:/tmp/bar_dir

Port-forward to a Kubernetes pod

Forward a local port to a pod port for local access without exposing a service.

kubectl port-forward <pod-name> <local-port>:<pod-port>

View resource metrics in Kubernetes

Show resource consumption for nodes, pods, containers, or services.

kubectl top [node | pod | container | service] [NAME | -l label]

Format output

Use the -o (or --output ) flag to control the output format of kubectl commands, supporting custom columns, Go templates, JSON, YAML, name only, wide, etc.

# List all images running in the cluster
kubectl get pods -A -o=custom-columns='DATA:spec.containers[*].image'

# Images in the default namespace, grouped by pod
kubectl get pods --namespace default --output=custom-columns="NAME:.metadata.name,IMAGE:.spec.containers[*].image"

# Exclude a specific image
kubectl get pods -A -o=custom-columns='DATA:spec.containers[?(@.image!="registry.k8s.io/coredns:1.6.2")].image'

# Show all metadata fields
kubectl get pods -A -o=custom-columns='DATA:metadata.*'

kubectl output verbosity and debugging

Control the verbosity of kubectl logs with --v followed by an integer (0‑9), where higher numbers provide more detailed debugging information.

--v=0   # minimal output
--v=3   # extended information
--v=6   # show requested resource
--v=9   # full HTTP request content without truncation

Conclusion

Mastering these essential kubectl commands enables efficient management of Kubernetes clusters, facilitating seamless application deployment, scaling, and performance optimization; further exploration of the official Kubernetes documentation and hands‑on practice in a test environment will build confidence for production operations.