Kubernetes

• PDF: https://sematext.com/kubernetes-cheat-sheet/
• WEBSITE: https://kubernetes.io/
• DOCUMENTATION: https://kubernetes.io/docs/home

Client Configuration

• Setup autocomplete in bash; bash-completion package should be installed first

source <(kubectl completion bash)

• View Kubernetes config

kubectl config view

• View specific config items by json path

kubectl config view -o jsonpath='{.users[?(@.name == "k8s")].user.password}'

• Set credentials for foo.kuberntes.com

kubectl config set-credentials kubeuser/foo.kubernetes.com --username=kubeuser --password=kubepassword

• Set active namespace

kubectl config set-context --current --namespace=namespace_name

Viewing, Finding resources

• List all services in the namespace

kubectl get services

• List all pods in all namespaces in wide format

kubectl get pods -o wide --all-namespaces

• List all pods in json (or yaml) format

kubectl get pods -o json

• Describe resource details (node, pod, svc)

kubectl describe nodes my-node

• List services sorted by name

kubectl get services --sort-by=.metadata.name

• List pods sorted by restart count

kubectl get pods --sort-by='.status.containerStatuses[0].restartCount'

• Rolling update pods for frontend-v1

kubectl rolling-update frontend-v1 -f frontend-v2.json

• Scale a replicaset named ‘foo’ to 3

kubectl scale --replicas=3 rs/foo

• Scale a resource specified in “foo.yaml” to 3

kubectl scale --replicas=3 -f foo.yaml

• Execute a command in every pod / replica

for i in 0 1; do kubectl exec foo-$i -- sh -c 'echo $(hostname) > /usr/share/nginx/html/index.html'; done

Manage Resources

• Get documentation for pod or service

kubectl explain pods,svc

• Create resource(s) like pods, services or daemonsets

kubectl create -f ./my-manifest.yaml

• Apply a configuration to a resource

kubectl apply -f ./my-manifest.yaml

• Start a single instance of Nginx

kubectl run nginx --image=nginx

• Create a secret with several keys

cat <<EOF | kubectl create -f -
apiVersion: v1
kind: Secret
metadata:
 name: mysecret
type: Opaque
data:
 password: $(echo "s33msi4" | base64)
 username: $(echo "jane"| base64)
EOF

• Delete a resource

kubectl delete -f ./my-manifest.yaml

Monitoring & Logging

• Deploy Heapster from Github repository

kubectl create -f deploy/kube-config/standalone/

• Show metrics for nodes

kubectl top node

• Show metrics for pods

kubectl top pod

• Show metrics for a given pod and its containers

kubectl top pod pod_name --containers

• Dump pod logs (stdout)

kubectl logs pod_name

• Stream pod container logs (stdout, multi-container case)

kubectl logs -f pod_name -c my-container

Interacting with running pods

• Run command in pod

kubectl exec pod_name -- command_name

• Run command in pod with multiple containers

kubectl exec pod_name -c container_name -- command_name

• Get terminal of pod

kubectl exec -it pod_name /bin/sh

• Get terminal of a container running in pod with multiple containers

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

Credits

https://raw.githubusercontent.com/LeCoupa/awesome-cheatsheets/refs/heads/master/tools/kubernetes.md