Kubernetes Cheatsheet

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}'

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

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

Monitoring & Logging

  • Deploy Heapster from Github repository https://github.com/kubernetes/heapster kubectl create -f deploy/kube-config/standalone/

  • Show metrics for nodes kubectl top node kubectl top node my-node-1

  • Show metrics for pods kubectl top pod kubectl top pod my-pod-1

  • 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

  • Create a daemonset from stdin. The example deploys Sematext Docker Agent to all nodes for the cluster-wide collection of metrics, logs and events. There is NO need to deploy cAdvisor, Heapster, Prometheus, Elasticsearch, Grafana, InfluxDb on your local nodes.

apiVersion: extensions/v1beta1
kind: DaemonSet
metadata:
  name: sematext-agent
spec:
  template:
    metadata:
      labels:
        app: sematext-agent
    spec:
      nodeSelector: {}
      hostNetwork: true
      dnsPolicy: "ClusterFirst"
      restartPolicy: "Always"
      containers:
      - name: sematext-agent
        image: sematext/sematext-agent-docker:latest
        imagePullPolicy: "Always"
        env:
        - name: SPM_TOKEN
          value: "YOUR_SPM_TOKEN"
        - name: LOGSENE_TOKEN
          value: "YOUR_LOGSENE_TOKEN"
        volumeMounts:
          - mountPath: /var/run/docker.sock
            name: docker-sock
          - mountPath: /etc/localtime
            name: localtime
        securityContext:
          privileged: true
      volumes:
        - name: docker-sock
          hostPath:
            path: /var/run/docker.sock
        - name: localtime
          hostPath:
            path: /etc/localtime
EOF