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Kubernetes cheatsheet

Kubernetes cheatsheet

Tkubernetes is beautiful!


Since I have a new project where I need to migrate an application that is currently running on Docker or Docker Swarm to a new Kubernetes platform, I checked my old docs about Kubernetes from 1 year ago to find a useful starting point. I merged the writings into a cheat sheet that is still under development and maybe helps you out after a long absence from working with k8s, like me.

The cheat sheet is published on my GitHub account at d4sw4r . Feel free to take a look and add additional useful commands.

Here is the first draft:

Kubernetes cheatsheet

commands

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# basic get

kubectl get services                          # List all services in the namespace
kubectl get pods --all-namespaces             # List all pods in all namespaces
kubectl get pods -o wide                      # List all pods in the current namespace, with more details
kubectl get deployment my-dep                 # List a particular deployment
kubectl get pods                              # List all pods in the namespace
kubectl get pod my-pod -o yaml                # Get a pod's YAML

# Describe commands with verbose output

kubectl describe nodes my-node
kubectl describe pods my-pod

# create & apply

kubectl apply -f ./my-manifest.yaml            # create resource(s)
kubectl apply -f ./my1.yaml -f ./my2.yaml      # create from multiple files
kubectl apply -f ./dir                         # create resource(s) in all manifest files in dir
kubectl apply -f https://git.io/vPieo          # create resource(s) from url
kubectl create deployment nginx --image=nginx  # start a single instance of nginx


# scaling

kubectl scale --replicas=3 rs/foo                                 # Scale a replicaset named 'foo' to 3
kubectl scale --replicas=3 -f foo.yaml                            # Scale a resource specified in "foo.yaml" to 3
kubectl scale --current-replicas=2 --replicas=3 deployment/mysql  # If the deployment named mysql's current size is 2, scale mysql to 3
kubectl scale --replicas=5 rc/foo rc/bar rc/baz                   # Scale multiple replication controllers

# deleteing

kubectl delete -f ./pod.json                                      # Delete a pod using the type and name specified in pod.json
kubectl delete pod unwanted --now                                 # Delete a pod with no grace period
kubectl delete pod,service baz foo                                # Delete pods and services with same names "baz" and "foo"
kubectl delete pods,services -l name=myLabel                      # Delete pods and services with label name=myLabel
kubectl -n my-ns delete pod,svc --all                             # Delete all pods and services in namespace my-ns,

# logging

kubectl logs my-pod                                 # dump pod logs (stdout)
kubectl logs -l name=myLabel                        # dump pod logs, with label name=myLabel (stdout)
kubectl logs my-pod --previous                      # dump pod logs (stdout) for a previous instantiation of a container
kubectl logs my-pod -c my-container                 # dump pod container logs (stdout, multi-container case)
kubectl logs -l name=myLabel -c my-container        # dump pod logs, with label name=myLabel (stdout)
kubectl logs my-pod -c my-container --previous      # dump pod container logs (stdout, multi-container case) for a previous instantiation of a container
kubectl logs -f my-pod                              # stream pod logs (stdout)

# taint

kubectl taint node <NAME> node-role.kubernetes.io/control-plane:NoSchedule-
kubectl taint node <NAME>  node-role.kubernetes.io/master:NoSchedule-

# node

kubectl cordon my-node                                                # Mark my-node as unschedulable
kubectl drain my-node                                                 # Drain my-node in preparation for maintenance
kubectl uncordon my-node                                              # Mark my-node as schedulable
kubectl top node my-node                                              # Show metrics for a given node
kubectl cluster-info                                                  # Display addresses of the master and services
kubectl cluster-info dump                                             # Dump current cluster state to stdout
kubectl cluster-info dump --output-directory=/path/to/cluster-state   # Dump current cluster state to /path/to/cluster-state

manifests

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# configmap
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: index-html-configmap
  namespace: default
data:
  index.html: |
    <html>
    <h1>Welcome</h1>
    </br>
    <h1>Hi! I am Deployed in K8s </h1>
    </html

# deployment
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  namespace: default
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 2 
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        ports:
        - containerPort: 80
        volumeMounts:
            - name: nginx-index-file
              mountPath: /usr/share/nginx/html/
      volumes:
      - name: nginx-index-file
        configMap:
          name: index-html-configmap
          
# service
---
apiVersion: v1
kind: Service
metadata:
  name: nginx-service
  namespace: default
spec:
  selector:
    app: nginx
  type: ClusterIP
  ports:
    - port: 80
      targetPort: 80
      
# ingress
---  
kind: Ingress
apiVersion: networking.k8s.io/v1
metadata:
  name: nginx-ingress
  annotations:
    traefik.ingress.kubernetes.io/router.entrypoints: web

spec:
  rules:
    - host: DOMAIN
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: nginx-service
                port:
                  number: 80      
# pv
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-mnt-data
  labels:
    type: local
spec:
  storageClassName: manual
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/mnt/data"

# pvc
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-claim-2
spec:
  storageClassName: manual
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi


This post is licensed under CC BY 4.0 by the author.