Kubectl Cheat Sheet

• focusing on kubectl commands commonly used for development, debugging, and maintenance tasks.
• This can be imported as markdown and saved as a Confluence page etc. for easy reference.

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Overview

This cheat sheet covers some essential kubectl commands for platform engineers. It includes syntax examples for inspecting resources, managing configurations, debugging, and performing essential tasks.

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1. Port Forwarding

Basic Port Forwarding

Forward a local port to a port on a pod, allowing access to internal services without exposing them publicly.

kubectl port-forward pod/<pod-name> <local-port>:<pod-port>
# Example
kubectl port-forward pod/my-pod 8080:80

Service Port Forwarding

Forward a local port to a port on a Kubernetes service.

kubectl port-forward service/<service-name> <local-port>:<service-port>
# Example
kubectl port-forward service/my-service 8080:80

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2. Executing Commands Inside a Pod

Running a Command in a Pod

Use exec to run commands in a container within a pod, useful for debugging or checking logs.

kubectl exec -it <pod-name> -- <command>
# Example
kubectl exec -it my-pod -- /bin/bash

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3. Describing Resources

Describe a Pod

Get detailed information about a specific pod, including events and environment variables.

kubectl describe pod <pod-name>
# Example
kubectl describe pod my-pod

Describe a Service

View detailed information about a service, including its endpoint mappings.

kubectl describe service <service-name>
# Example
kubectl describe service my-service

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4. Listing Resources

List All Pods in a Namespace

Display all pods in a given namespace.

kubectl get pods -n <namespace>
# Example
kubectl get pods -n default

List All Services

Show all services in the current namespace.

kubectl get services

List Nodes

Check the nodes in the Kubernetes cluster.

kubectl get nodes

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5. Logs and Monitoring

View Pod Logs

Access logs for a specific container in a pod.

kubectl logs <pod-name> -c <container-name>
# Example
kubectl logs my-pod -c my-container

View Logs for All Containers in a Pod

Use the --all-containers flag to get logs from all containers.

kubectl logs <pod-name> --all-containers=true
# Example
kubectl logs my-pod --all-containers=true

Stream Logs Continuously

Stream logs in real-time.

kubectl logs -f <pod-name> -c <container-name>
# Example
kubectl logs -f my-pod -c my-container

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6. Managing Deployments

Create a Deployment

Create a deployment directly from an image.

kubectl create deployment <deployment-name> --image=<image-name>
# Example
kubectl create deployment my-deployment --image=nginx

Scale a Deployment

Scale a deployment up or down to a specific number of replicas.

kubectl scale deployment <deployment-name> --replicas=<number>
# Example
kubectl scale deployment my-deployment --replicas=3

Update a Deployment Image

Change the image of a deployment.

kubectl set image deployment/<deployment-name> <container-name>=<new-image>
# Example
kubectl set image deployment/my-deployment nginx=nginx:1.19

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7. Namespace Management

List Namespaces

Get a list of all namespaces in the cluster.

kubectl get namespaces

Switch to a Different Namespace

You can set a specific namespace as the default for commands using a context update.

kubectl config set-context --current --namespace=<namespace>
# Example
kubectl config set-context --current --namespace=production

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8. Applying Configuration Files

Apply a Manifest

Apply configuration from a YAML file to create or update resources.

kubectl apply -f <file.yaml>
# Example
kubectl apply -f deployment.yaml

Delete Resources from a File

Delete resources defined in a manifest file.

kubectl delete -f <file.yaml>
# Example
kubectl delete -f deployment.yaml

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9. Inspecting and Troubleshooting

Check Events in a Namespace

View all events in a namespace to troubleshoot issues.

kubectl get events -n <namespace>
# Example
kubectl get events -n default

Debug a Pod by Copying Files

Copy files to and from a pod for further inspection.

# Copy from local to pod
kubectl cp <local-file-path> <pod-name>:<pod-file-path>

# Copy from pod to local
kubectl cp <pod-name>:<pod-file-path> <local-file-path>
# Example
kubectl cp my-pod:/var/log/app.log ./app.log

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10. Working with Secrets

Create a Secret from Literal Values

Create a new Kubernetes secret from literal values (e.g., storing credentials).

kubectl create secret generic <secret-name> --from-literal=<key>=<value>
# Example
kubectl create secret generic my-secret --from-literal=username=admin --from-literal=password=secret

View Secret Data in Base64

Retrieve the secret data in a base64-encoded format.

kubectl get secret <secret-name> -o jsonpath='{.data.<key>}' | base64 --decode
# Example
kubectl get secret my-secret -o jsonpath='{.data.password}' | base64 --decode

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