Course-Kubernetes-Commands-and-YAML.txt

Course-Kubernetes-Commands-and-YAML.txt

1.a-  kubectl run

kubectl get pods
kubectl run first-deployment --image=nginx
kubectl get pods
(maybe one more time to show the state changed from container creation to Running)
(copy the pod name from get pods)
kubectl exec -it pod-name -- /bin/bash
echo Hello nginx! > /usr/share/nginx/html/index.html
apt-get update
apt-get install curl
curl localhost
=======================

1.c- kubectl create -f

kubectl get pods
nano declarative-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: declarative-pod
spec:
  containers:
  - name: memory-demo-ctr
    image: nginx

kubectl create -f declarative-pod.yaml
(copy the pod name from get pods)
kubectl exec -it memory-demo-ctr -- /bin/bash
echo Hello nginx! We are so Declarative!-- > /usr/share/nginx/html/index.html
apt-get update
apt-get install curl
curl localhost
=======================

1.d- kubectl apply -f

kubectl get pods
kubectl describe po declarative-pod
nano declarative-pod.yaml
(change the image from nginx to busybox)
(save changes and exit)
kubectl apply -f declarative-pod.yaml
kubectl get pods
kubectl describe (updated pod)
==========================

1.e- Pod - node matching

kubectl get nodes 
kubectl label nodes <nodename> disktype=ssd
kubectl get nodes --show-labels
nano dev-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: nginx
  labels:
    env: test
spec:
  containers:
  - name: nginx
    image: nginx
    imagePullPolicy: IfNotPresent
  nodeSelector:
    disktype: ssd

kubectl create -f dev-pod.yaml
kubectl get pods -o wide
==================================

1.f-  Preset

kubectl get pods
kubectl get podpreset
nano pod-preset.yaml

apiVersion: settings.k8s.io/v1alpha1
kind: PodPreset
metadata:
  name: allow-database
spec:
  selector:
    matchLabels:
      role: frontend
  env:
    - name: DB_PORT
      value: "6379"
  volumeMounts:
    - mountPath: /cache
      name: cache-volume
  volumes:
    - name: cache-volume
      emptyDir: {}

kubectl create -f pod-preset.yaml

kubectl get podpreset

nano website.yaml

apiVersion: v1
kind: Pod
metadata:
  name: website
  labels:
    app: website
    role: frontend
spec:
  containers:
    - name: website
      image: nginx
      ports:
        - containerPort: 80

kubectl create -f website.yaml
kubectl get pods
kubectl describe pod website
=========================


1.g-  Resource limits

kubectl get pods
nano resource-limited-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: frontend
spec:
  containers:
  - name: db
    image: mysql
    env:
    - name: MYSQL_ROOT_PASSWORD
      value: "password"
    resources:
      requests:
        memory: "64Mi"
        cpu: "250m"
      limits:
        memory: "128Mi"
        cpu: "500m"
  - name: wp
    image: wordpress
    resources:
      requests:
        memory: "64Mi"
        cpu: "250m"
      limits:
        memory: "128Mi"
        cpu: "500m"

kubectl create -f resource-limited-pod.yaml

kubectl get pods

kubectl describe pods frontend
=============================

1.h- Pod initialization

kubectl get pods
nano init.yaml

apiVersion: v1
kind: Pod
metadata:
  name: init-demo
spec:
  containers:
  - name: nginx
    image: nginx
    ports:
    - containerPort: 80
    volumeMounts:
    - name: workdir
      mountPath: /usr/share/nginx/html
  # These containers are run during pod initialization
  initContainers:
  - name: install
    image: busybox
    command:
    - wget
    - "-O"
    - "/work-dir/index.html"
    - http://kubernetes.io
    volumeMounts:
    - name: workdir
      mountPath: "/work-dir"
  dnsPolicy: Default
  volumes:
  - name: workdir
    emptyDir: {}

kubectl create -f init.yaml

kubectl get pods
kubectl exec -it init-demo -- /bin/bash
apt-get update
apt-get install curl
curl localhost
=================================

1.i-  Liveness and readiness probes

kubectl get pods

nano exec-liveness.yaml

apiVersion: v1
kind: Pod
metadata:
  labels:
    test: liveness
  name: liveness-exec
spec:
  containers:
  - name: liveness
    image: k8s.gcr.io/busybox
    args:
    - /bin/sh
    - -c
    - touch /tmp/healthy; sleep 30; rm -rf /tmp/healthy; sleep 600
    livenessProbe:
      exec:
        command:
        - cat
        - /tmp/healthy
      initialDelaySeconds: 5
      periodSeconds: 5

kubectl create exec-liveness.yaml
(wait 5 sec)
kubectl describe pod liveness-exec
(wait 30 sec)
kubectl describe pod liveness-exec

nano http-liveness.yaml

apiVersion: v1
kind: Pod
metadata:
  labels:
    test: liveness
  name: liveness-http
spec:
  containers:
  - name: liveness
    image: k8s.gcr.io/liveness
    args:
    - /server
    livenessProbe:
      httpGet:
        path: /healthz
        port: 8080
        httpHeaders:
        - name: X-Custom-Header
          value: Awesome
      initialDelaySeconds: 3
      periodSeconds: 3

kubectl create -f http-liveness.yaml
(wait 30 sec)
kubectl describe pod liveness-http

nano tcp-liveness-readiness.yaml

apiVersion: v1
kind: Pod
metadata:
  name: goproxy
  labels:
    app: goproxy
spec:
  containers:
  - name: goproxy
    image: k8s.gcr.io/goproxy:0.1
    ports:
    - containerPort: 8080
    readinessProbe:
      tcpSocket:
        port: 8080
      initialDelaySeconds: 5
      periodSeconds: 10
    livenessProbe:
      tcpSocket:
        port: 8080
      initialDelaySeconds: 15
      periodSeconds: 20

kubectl create -f tcp-liveness-readiness.yaml
(wait 20 sec)
kubectl describe pod goproxy
======================================

1.j-  Container lifecycle events

kubectl get pods
nano lifecycle.yaml

apiVersion: v1
kind: Pod
metadata:
  name: lifecycle-demo
spec:
  containers:
  - name: lifecycle-demo-container
    image: nginx
    lifecycle:
      postStart:
        exec:
          command: ["/bin/sh", "-c", "echo Hello from the postStart handler > /usr/share/message"]
      preStop:
        exec:
          command: ["/usr/sbin/nginx","-s","quit"]

kubectl create -f lifecycle.yaml

kubectl get pod lifecycle-demo
kubectl exec -it lifecycle-demo -- /bin/bash
cat /usr/share/message

2.a- kubectl delete

kubectl get pods
kubectl delete pods --all
kubectl get pods
(copy podname)
kubectl delete pod (copied podname)
kubectl get pods



2.b-  kubectl scale

kubectl get pods
kubectl get deployments
(copy the name of deployment)
kubectl scale deployments (deployment name) --replicas=3
kubectl get pods

2.c-  kubectl edit

kubectl get deployments
(copy the name of deployment)
KUBE_EDITOR="nano" kubectl edit deployments (deployment name)
add a label
save the file

3.a-  kubectl create rs

kubectl get pods
nano frontend.yaml

apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: frontend
  labels:
    app: guestbook
    tier: frontend
spec:
  replicas: 3
  selector:
    matchLabels:
      tier: frontend
    matchExpressions:
      - {key: tier, operator: In, values: [frontend]}
  template:
    metadata:
      labels:
        app: guestbook
        tier: frontend
    spec:
      containers:
      - name: php-redis
        image: gcr.io/google_samples/gb-frontend:v3
        ports:
        - containerPort: 80

kubectl create -f frontend.yaml
kubectl get pods
kubectl describe rs/frontend
============================

3.b-  delete rs and pods

kubectl get pods
kubectl get rs
kubectl delete pods --all
(wait a minute)
kubectl get pods
kubectl delete rs/frontend
kubectl get pods
==========================

3.c-  delete rs but keep pods

kubectl get pods
kubectl create -f frontend.yaml
kubectl delete rs/frontend --cascade=false
kubectl get pods
kubectl delete pods
=========================

3.d-  update labels on pod, so that new pod fired by replicaset

kubectl get pods
(copy the name of first pod)
kubectl describe (first pod)
KUBE_EDITOR="nano" kubectl edit pod (first pod)
kubectl describe (first pod)
kubectl get pods
kubectl describe (new pod)
==========================




3.e-  scale replicaset

kubectl get pods
kubectl get rs
nano frontend.yaml
(change number of replicas from 3 to 5)
kubectl apply -f frontend.yaml
(wait a minute)
kubectl get pods


4.a-  create using kubectl run

kubectl get pods
kubectl run example --image=nginx
kubectl get pods
kubectl describe pod (pod name)
kubectl describe deployment example
kubectl get pods
kubectl exec -it podname -- /bin/bash
echo Hello nginx! > /usr/share/nginx/html/index.html
apt-get update
apt-get install curl
curl localhost
=====================

4.b-  create -f
kubectl get pods
nano nginx-deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.7.9
        ports:
        - containerPort: 80

kubectl create -f nginx-deployment.yaml
kubectl get pods
kubectl get deployments
kubectl describe deployment nginx-deployment
kubectl get pods
(copy any of the latest pod)
kubectl exec -it podname -- /bin/bash
echo Hello nginx! > /usr/share/nginx/html/index.html
apt-get update
apt-get install curl
curl localhost
========================


4.c-  apply -f
kubectl get pods
kubectl get deployments
nano nginx-deployment.yaml
(change number of replicas to 3)
kubectl apply -f nginx-deployment.yaml
kubectl get pods
nano nginx-deployment.yaml
(remove replica attribute)
kubectl apply -f nginx-deployment.yaml
kubectl get pods
kubectl delete pods --all
kubectl get pods
============================
4.d- rolling update

kubectl get pods
kubectl get deployments
kubectl set image deployment/nginx-deployment nginx=nginx:1.9.1
kubectl rollout status deployment/nginx-deployment
kubectl get deployments
kubectl get pods
kubectl describe pods (podname)
kubectl exec -it podname -- /bin/bash
echo Hello nginx! > /usr/share/nginx/html/index.html
apt-get update
apt-get install curl
curl localhost
===========================

4.e-  rolling back

kubectl get pods
kubectl get deployments -o wide
(optional: kubectl describe deployments nginx-deployment)
kubectl rollout undo deployment/nginx-deployment
kubectl get deployments -o wide
(optional: kubectl describe deployments nginx-deployment)
===========================

4.f-  scaling

kubectl get pods
kubectl get deployments
kubectl scale deployments example --replicas=3
kubectl get pods
==========================

4.g- pause/resume

kubectl get deployments -o wide
kubectl scale deployments nginx-deployment --replicas=10
kubectl rollout status deployment/nginx-deployment
kubectl set image deployment/nginx-deployment nginx=nginx:1.9.1
kubectl rollout pause deployment/nginx-deployment
kubectl rollout status deployment/nginx-deployment
kubectl rollout resume deployment/nginx-deployment
(after a while)
kubectl rollout status deployment/nginx-deployment


7.a- Run-to-completion job

kubectl get pods
nano job.yaml

apiVersion: batch/v1
kind: Job
metadata:
  name: pi
spec:
  template:
    spec:
      containers:
      - name: pi
        image: perl
        command: ["perl",  "-Mbignum=bpi", "-wle", "print bpi(2000)"]
      restartPolicy: Never
  backoffLimit: 4

kubectl create -f job.yaml

kubectl describe jobs/pi
pods=$(kubectl get pods  --show-all --selector=job-name=pi --output=jsonpath={.items..metadata.name})
echo $pods
kubectl logs $pods

7.b-  Cronjob

kubectl run hello --schedule="*/1 * * * *" --restart=OnFailure --image=busybox -- /bin/sh -c "date; echo Hello from the Kubernetes cluster"
kubectl get cronjob hello (try again after a minute)

pods=$(kubectl get pods -a --selector=job-name=jobname --output=jsonpath={.items..metadata.name})
echo $pods
kubectl logs $pods

8.a-  regular volume

kubectl get pods

nano pod-redis.yaml

apiVersion: v1
kind: Pod
metadata:
  name: redis
spec:
  containers:
  - name: redis
    image: redis
    volumeMounts:
    - name: redis-storage
      mountPath: /data/redis
  volumes:
  - name: redis-storage
    emptyDir: {}

kubectl create -f pod-redis.yaml
kubectl get pod redis --watch
kubectl exec -it redis -- /bin/bash
cd /data/redis/
echo Hello > test-file
ps aux
kill <pid>
(exit if needed)
kubectl get pod redis --watch
kubectl exec -it redis -- /bin/bash
ls /data/redis
==================================

8.b- persistent volume

mkdir /mnt/data
echo 'Hello from Kubernetes storage' > /mnt/data/index.html

nano task-pv-volume.yaml

kind: PersistentVolume
apiVersion: v1
metadata:
  name: task-pv-volume
  labels:
    type: local
spec:
  storageClassName: manual
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/mnt/data"

kubectl create -f task-pv-volume.yaml
kubectl get pv task-pv-volume

nano task-pv-claim.yaml

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: task-pv-claim
spec:
  storageClassName: manual
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 3Gi

kubectl create -f task-pv-claim

kubectl get pv task-pv-volume
kubectl get pvc task-pv-claim

nano task-pv-pod.yaml

kind: Pod
apiVersion: v1
metadata:
  name: task-pv-pod
spec:
  volumes:
    - name: task-pv-storage
      persistentVolumeClaim:
       claimName: task-pv-claim
  containers:
    - name: task-pv-container
      image: nginx
      ports:
        - containerPort: 80
          name: "http-server"
      volumeMounts:
        - mountPath: "/usr/share/nginx/html"
          name: task-pv-storage

kubectl create -f task-pv-pod.yaml

kubectl exec -it task-pv-pod -- /bin/bash
apt-get update
apt-get install curl
curl localhost
=====================================

8.c- secret

echo -n 'my-app' | base64
echo -n '39528$vdg7Jb' | base64

nano secret.yaml

apiVersion: v1
kind: Secret
metadata:
  name: test-secret
data:
  username: bXktYXBw
  password: Mzk1MjgkdmRnN0pi

kubectl create -f secret.yaml
kubectl get secret test-secret
kubectl describe secret test-secret

nano secet-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: secret-test-pod
spec:
  containers:
    - name: test-container
      image: nginx
      volumeMounts:
          # name must match the volume name below
          - name: secret-volume
            mountPath: /etc/secret-volume
  # The secret data is exposed to Containers in the Pod through a Volume.
  volumes:
    - name: secret-volume
      secret:
        secretName: test-secret

kubectl create -f secret-pod.yaml

kubectl get pod secret-test-pod
kubectl exec -it secret-test-pod -- /bin/bash
cd /etc/secret-volume
ls
cat username; echo; cat password; echo
===================================

8.d- configmap

nano configmap.yaml

apiVersion: v1
kind: ConfigMap
metadata:
  name: special-config
  namespace: default
data:
  special.level: very
  special.type: charm

nano config-pod.yaml

apiVersion: v1
kind: Pod
metadata:
  name: dapi-test-pod
spec:
  containers:
    - name: test-container
      image: k8s.gcr.io/busybox
      command: [ "/bin/sh", "-c", "env" ]
      envFrom:
      - configMapRef:
          name: special-config
  restartPolicy: Never


kubectl get pods
kubectl exec -it podname -- /bin/bash
"ls /etc/config/"


11.a- Environment variables

kubectl get pods

nano envars.yaml

apiVersion: v1
kind: Pod
metadata:
  name: envar-demo
  labels:
    purpose: demonstrate-envars
spec:
  containers:
  - name: envar-demo-container
    image: gcr.io/google-samples/node-hello:1.0
    env:
    - name: DEMO_GREETING
      value: "Hello from the environment"
    - name: DEMO_FAREWELL
      value: "Such a sweet sorrow"

kubectl create -f envars.yaml
kubectl get pods -l purpose=demonstrate-envars
kubectl exec -it envar-demo -- /bin/bash
printenv
============================

11.b- Share information using files

kubectl get pods

nano dapi-volume.yaml

apiVersion: v1
kind: Pod
metadata:
  name: kubernetes-downwardapi-volume-example
  labels:
    zone: us-est-coast
    cluster: test-cluster1
    rack: rack-22
  annotations:
    build: two
    builder: john-doe
spec:
  containers:
    - name: client-container
      image: k8s.gcr.io/busybox
      command: ["sh", "-c"]
      args:
      - while true; do
          if [[ -e /etc/podinfo/labels ]]; then
            echo -en '\n\n'; cat /etc/podinfo/labels; fi;
          if [[ -e /etc/podinfo/annotations ]]; then
            echo -en '\n\n'; cat /etc/podinfo/annotations; fi;
          sleep 5;
        done;
      volumeMounts:
        - name: podinfo
          mountPath: /etc/podinfo
          readOnly: false
  volumes:
    - name: podinfo
      downwardAPI:
        items:
          - path: "labels"
            fieldRef:
              fieldPath: metadata.labels
          - path: "annotations"
            fieldRef:
              fieldPath: metadata.annotations

kubectl create -f dapi-volume.yaml
kubectl get pods
kubectl logs kubernetes-downwardapi-volume-example
kubectl exec -it kubernetes-downwardapi-volume-example -- sh
cat /etc/podinfo/labels
cat /etc/podinfo/annotations
ls -laR /etc/podinfo
exit


12.c- Loadbalancer

kubectl get pods
kubectl run hello-world --replicas=2 --labels="run=load-balancer-example" --image=gcr.io/google-samples/node-hello:1.0  --port=8080
kubectl get pods
kubectl expose deployment <your-deployment> --type="LoadBalancer" --name="example-service"
kubectl get services
kubectl get services example-service --watch
curl <your-external-ip-address>:8080
===================================

12.d-  kubectl port-forward

kubectl get pods
kubectl create -f https://k8s.io/docs/tasks/access-application-cluster/redis-master.yaml
kubectl get pods
kubectl get pods redis-master --template='{{(index (index .spec.containers 0).ports 0).containerPort}}{{"\n"}}'
kubectl port-forward redis-master 6379:6379
redis-cli
127.0.0.1:6379>ping

============================================
M3D4- Scheduling pods using taints

kubectl get nodes
kubectl taint nodes (nodename) env=dev:NoSchedule
kubectl run nginx —image=nginx
kubectl label deployments/nginx env=dev
kubectl scale deployments/nginx —replicas=5
kubectl get pods -o wide
============================================
m3D5- Tolerations

kubectl get nodes
kubectl taint nodes (nodename) env=dev:NoSchedule
kubectl describe nodes (nodename)
nano dep.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 7
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.7.9
        ports:
        - containerPort: 80
      tolerations:
      - key: “dev”
        operator: “Equal”
        value: “env”
        effect: “NoSchedule”
    

    

kubectl get pods -o wide

M3D16- Volumes Demo

gcloud compute disks list
nano volume-sample.yaml

apiVersion: v1
kind: Pod
metadata:
  name: test-pd
spec:
  containers:
  - image: k8s.gcr.io/test-webserver
    name: test-container
    volumeMounts:
    - mountPath: /test-pd
      name: test-volume
  volumes:
  - name: test-volume
    gcePersistentDisk: (diskname)
      pdName:
      fsType: ext4

kubectl create -f vlume-sample.yaml
kubectl describe po test-pd

========================================
 M4d4- Stateful Sets deployment order Demo

nano Sts.yaml

apiVersion: v1
kind: Service
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    name: web
  clusterIP: None
  selector:
    app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  serviceName: "nginx"
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: k8s.gcr.io/nginx-slim:0.8
        ports:
        - containerPort: 80
          name: web
        volumeMounts:
        - name: www
          mountPath: /usr/share/nginx/html
  volumeClaimTemplates:
  - metadata:
      name: www
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 1Gi

kubectl apply -f Sts.yaml
kubectl get pods -w -l app=nginx
kubectl scale Sts web —replicas=4
kubectl get pods -w -l app=nginx

=======================================
Accessing secrets Demo

kubectl get secrets
kubectl describe secrets/sensitive
kano secret-pod.yaml

apiVersion: v1
kind: Pod
metadata
  name: secret-pod