kubectl {get/apply/delete} {all/pods/nodes/services/deployments} {NAME_or_yaml_file}
kubectl get pods -o wide #similar to docker ps -a

kubectl describe {NAME}

kubectl cluster-info
# Kubernetes control plane is running at https://172.17.0.28:8443
# KubeDNS is running at https://172.17.0.28:8443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
kubectl get nodes
# NAME       STATUS   ROLES                  AGE    VERSION
# minikube   Ready    control-plane,master   108s   v1.20.2

kubectl describe node

kubectl config current-context #get current context
kubectl config get-contexts #list context
kubectl config use-context {context name} #set the current context
kubectl config delete-context {context name} #delete context from config file

kubectl get ns
kubectl apply ns {namespace name}
kubectl delete ns {namespace name}
kubectl get pods --all-namespaces #list all pods in all namespaces
kubectl config set-context --current --namespace={some namespace}

apiVersion: v1
kind: Pod
metadata:
  name: superpod
  labels: 
    app: myapp
spec:
  containers:
  - name: myappcontainer
    image: busybox
  initContainers:
  - name: init-myservices
    image: busybox:1.28
    command: ['sh','-c', "until nslookup mysvc.namespace.svc.cluster.local; do echo waiting for mysevice; sleep 2; done"]
  - name: init-mydb
    image: busybox:1.28
    command: ['sh','-c',"until nslookup mydb.namespace.svc.cluster.local; do echo waiting for mydb; sleep 2; done"]

kubectl describe pod superpod
kubectl get pod superpod -o yaml > mypod2.yaml # export pod into yaml file
kubectl exec -it superpod -- sh
kubectl delete -f mypod.yaml

var http = require('http');
var handleRequest = function(request, response) {
  response.writeHead(200);
  response.end("Hello World!");
}
var www = http.applyServer(handleRequest);
www.listen(8080);

FROM node:12.22.12
EXPOSE 8080
COPY index.js .
CMD node index.js

apiVersion: v1
kind: Pod
metadata:
  name: superpod
  labels: 
    app: myapp
spec:
  containers:
  - name: myappcontainer
    image: localhost:8444/demo
    imagePullPolicy: Always
    ports: 
    - containerPort: 8080

kubectl delete pod superpod # if we already have one running
kubectl apply -f deploy.yaml #on creation kubectl will run it automatically
kubectl get pods -o wide
# NAME       READY   STATUS    RESTARTS   AGE    IP           NODE     NOMINATED NODE   READINESS GATES
# superpod   1/1     Running   0          102s   10.42.0.37   debian   <none>           <none>

kubectl exec -it superpod -- bash

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  selector:
    matchLabels:
      run: myapp
  replicas: 2
  template:
    metadata:
      labels:
        run: myapp
    spec:
      containers:
      - name: myapp
        image: localhost:8444/demo
        ports:
        - containerPort: 8080

kubectl delete deployments superpod
kubectl apply -f deploy1.yaml
kubectl get deployments -o wide
# NAME    READY   UP-TO-DATE   AVAILABLE   AGE     CONTAINERS   IMAGES                SELECTOR
# myapp   2/2     2            2           3m27s   myapp        localhost:8444/demo   run=myapp
kubectl get pods -o wide
# NAME                     READY   STATUS    RESTARTS   AGE   IP           NODE     NOMINATED NODE   READINESS GATES
# myapp-5b84d97bb8-tnjmr   1/1     Running   0          6s    10.42.0.38   debian   <none>           <none>
# myapp-5b84d97bb8-v925s   1/1     Running   0          6s    10.42.0.39   debian   <none>           <none>

kubectl delete pod myapp-5b84d97bb8-tnjmr
kubectl get pods -o wide 
# NAME                     READY   STATUS    RESTARTS   AGE     IP           NODE     NOMINATED NODE   READINESS GATES
# myapp-5b84d97bb8-v925s   1/1     Running   0          6m24s   10.42.0.39   debian   <none>           <none>
# myapp-5b84d97bb8-v6zmj   1/1     Running   0          35s     10.42.0.40   debian   <none>           <none>

kubectl apply deployment mynginx --image=nginx #imperative
kubectl apply -f deploy-example.yaml #declarative

# deploys blehname to a pod
kubectl apply deployment blehname --image=gcr.io/google-samples/kubernetes-bootcamp:v1

kubectl get deployments

kubectl apply -f https://k8s.io/examples/service/load-balancer-example.yaml

kubectl get deployments hello-world
kubectl describe deployments hello-world

kubectl get replicasets
kubectl describe replicasets

kubectl expose deployment hello-world --type=LoadBalancer --name=my-service

kubectl get services my-service

kubectl expose deployment hello-world --type=LoadBalancer --name=my-service
# NAME         TYPE           CLUSTER-IP    EXTERNAL-IP     PORT(S)          AGE
# my-service   LoadBalancer   10.43.73.29   192.168.1.244   8080:32447/TCP   7s

apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  selector:
    app: nginx #<--- used to connect service to deployments
  ports:
    - protocol: TCP
      port: 80
      targetPort: 8080

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx   #<--- used to connect service to deployments
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx  #<--- used to connect service to deployments
  template:
    metadata:
      labels:
        app: nginx  #<--- used to connect service to deployments
    spec:
      containers:
      - name: nginx  
        image: nginx:1.16
        ports:
        - containerPort: 8080