The Ultimate Kubectl Cheat Sheet: Essential Commands for Managing Kubernetes

Kubernetes (K8s) has become the go-to platform for container orchestration, helping teams deploy, manage, and scale applications across clusters. But to effectively interact with Kubernetes, you need to master kubectl, the command-line interface that allows you to communicate with your Kubernetes cluster.

This cheat sheet will guide you through the most essential kubectl commands that every Kubernetes admin or developer should know.

Getting Started with Kubectl

Check Version

Before you begin, ensure you're running compatible versions of kubectl and Kubernetes.

kubectl version --client

Set Kubernetes Context

Switch between different clusters or namespaces.

kubectl config use-context <context-name>

View Current Context

Display the current Kubernetes context you are operating in.

kubectl config current-context

Working with Pods

List Pods

View all pods in the default namespace:

kubectl get pods

To see pods in a specific namespace:

kubectl get pods -n <namespace>

Detailed Pod Information

Get detailed information about a specific pod:

kubectl describe pod <pod-name>

Create a Pod

You can quickly create a pod from a YAML configuration file:

kubectl apply -f <pod-definition.yaml>

Delete a Pod

Delete a pod by name:

kubectl delete pod <pod-name>

Get Pod Logs

Access the logs from a specific pod:

kubectl logs <pod-name>

For multi-container pods, specify the container name:

kubectl logs <pod-name> -c <container-name>

Execute Commands in a Running Pod

Execute a command inside a running pod:

kubectl exec -it <pod-name> -- /bin/bash

Managing Deployments

List Deployments

List all deployments in the default namespace:

kubectl get deployments

Scale a Deployment

Scale a deployment by increasing or decreasing the number of replicas:

kubectl scale deployment <deployment-name> --replicas=<count>

Update a Deployment

Update a deployment to use a new Docker image:

kubectl set image deployment/<deployment-name> <container-name>=<new-image>

Roll Back a Deployment

If something goes wrong, you can roll back to a previous version:

kubectl rollout undo deployment/<deployment-name>

View Rollout Status

Check the status of a rollout:

kubectl rollout status deployment/<deployment-name>

Interacting with Services

List Services

List all services in the default namespace:

kubectl get services

Expose a Deployment as a Service

Expose a deployment as a service to make it accessible:

kubectl expose deployment <deployment-name> --type=LoadBalancer --port=<port>

Delete a Service

Delete a service by name:

kubectl delete service <service-name>

Working with ConfigMaps and Secrets

Create a ConfigMap

Create a ConfigMap from a file:

kubectl create configmap <configmap-name> --from-file=<path-to-file>

List ConfigMaps

List all ConfigMaps:

kubectl get configmaps

Create a Secret

Create a secret using a key-value pair:

kubectl create secret generic <secret-name> --from-literal=<key>=<value>

List Secrets

List all secrets:

kubectl get secrets

Namespace Management

List Namespaces

List all available namespaces:

kubectl get namespaces

Create a Namespace

Create a new namespace:

kubectl create namespace <namespace-name>

Delete a Namespace

Delete a namespace:

kubectl delete namespace <namespace-name>

Managing Nodes

List Nodes

List all the nodes in your Kubernetes cluster:

kubectl get nodes

View Node Details

Get detailed information about a specific node:

kubectl describe node <node-name>

Cordon a Node

Mark a node as unschedulable (no new pods will be scheduled on it):

kubectl cordon <node-name>

Uncordon a Node

Mark a node as schedulable again:

kubectl uncordon <node-name>

Drain a Node

Safely evict all pods from a node, preparing it for maintenance:

kubectl drain <node-name>

Monitoring and Troubleshooting

View Cluster Events

Get a list of recent cluster events:

kubectl get events

Resource Usage

View the resource usage of pods (CPU, memory):

kubectl top pod

View resource usage of nodes:

kubectl top node

Get YAML Output for Resources

Get the full YAML manifest of a resource (e.g., pod, service, etc.):

kubectl get <resource-type> <resource-name> -o yaml

Advanced Kubectl Tips

Dry Run for Commands

If you're unsure about a command, you can run it with --dry-run to simulate its execution without making any changes:

kubectl apply -f <file.yaml> --dry-run=client

Apply Changes with Force

In some situations, you may need to force apply changes:

kubectl apply -f <file.yaml> --force

Label Resources

Label resources to group them logically:

kubectl label pod <pod-name> <key>=<value>

Taint a Node

Taint a node to prevent pods from being scheduled on it, except by toleration:

kubectl taint nodes <node-name> key=value:NoSchedule

Conclusion

This kubectl cheat sheet provides a quick and easy reference for managing your Kubernetes clusters. While these commands cover the most common scenarios, Kubernetes offers a vast array of features and tools for cluster management. As you become more familiar with Kubernetes, consider exploring more advanced features like Helm for package management, CRDs (Custom Resource Definitions), and building custom controllers to meet the specific needs of your infrastructure.

Happy clustering!