Kubernetes Mock Exam 2

 Etcd db backup

1. Check etcd version: #ECTDCTL_API=3 etcdctl --version

2. Check etcd config file: /etc/kubernetes/manifests

3. Copy the file key information

4. Make the backup:  

ECTDCTL_API=3 etcdctl snapshot save /tmp/etcd-backup.db

5. Verify the backup:

ECTDCTL_API=3 <key information> etcdctl snapshot status <destination> -w table

Create pod with specific CPU and Memory

#kubectl run --generator=run-pod/v1 elephant --image=redis --dry-run -o yaml > elephant.yaml

#vi elephant.yaml

add resources section

containers:

  - image: redis

    name: elephant

    resources:

        cpu: "1"

        memory: "200Mi"

#kubectl create -f elephant.yaml

#kubectl describe pod elephant

Create pod with volume

#kubectl run --generator=run-pod/v1 redis-storage --image=redis --dry-run -o yaml > redis.yaml

#vi redis.yaml

Add volumn section

spec: 

  containers:

  - image: redis:alpine

    name: redis-storage

    volumeMounts:

    - mountPath: /data/redis

      name: data-volume

   volumes:

   - name: data-volume

     emptyDir: {}

Create pod able to set system_time

#cp elephant.yaml super-user-pod.yaml

#vi super-user-pod.yaml

Change name / image; remove resources part / add following

spec: 

    containers:

    - name: super-user-pod

      image: busybox:1.28

      command: ["sleep","4800"]

      securityContext:

        capabilities:

            add: ["NET_ADMIN", "SYS_TIME"]

#kubectl create -f super-user-pod.yaml

#kubectl describe pod super-user-pod

Update pod yaml file to use persistent volume

check persistent volume: #kubectl get pv

create persistent volume claim:

#vi pvc.yaml

apiVersion: v1

kind: PersistentVolumeClaim

metadata:

  name: my-pvc

spec:

  accessModes:

    - ReadWriteOnce

  volumeMode: Filesystem

  resources:

    requests:

      storage: 10Mi

#kubectl create -f pvc.yaml

check: #kubectl get pv

update pod yaml file to use persistent volume claim

#vi use-pv.yaml

spec:

  containers:

    - name: user-pv

      image: nginx

      volumeMounts:

      - mountPath: "/data"

        name: mypd

  volumes:

    - name: mypd

      persistentVolumeClaim:

        claimName: my-pvc

#kubectl create -f user-pv-yaml

#kubectl describe pod user-pv

update version of deployment

#kubectl run nginx-deploy --image=nginx:1.16 --replicas=1 --record

#kubectl get deployment

#kubectl rollout history deployment nginx-deploy

#kubectl set image deployment/nginx-deploy nginx-deploy=nginx:1.17  --record

#kubectl describe deployment nginx-deploy | grep -I image

#kubectl rollout history deployment nginx-deploy

create user access grant privilege

check the key file

#kubectl api-versions | grep certif

#vi john.yaml

apiVersion: certificates.k8s.io/v1beta1

kind: CertificateSigningRequest

metadata:

  name: john-developer

spec:

  request: $(cat /root/john.csr | base64 | tr -d '\n')

  usages:

  - digital signature

  - key encipherment

  - server auth

#kubectl create -f john.yaml

#kubectl get csr

#kubectl certificate approve john-developer

#kubectl get csr

#kubectl create role developer --resource=pods  --verb=create,list,get,update,delete --namespace=development

#kubectl describe role developer -n development

#kubectl create rolebinding developer-role-binding --role=developer --user=john --namespace=development

#kubectl auth can-i update pods --namespace=development --as=john

#kubectl auth can-i list pods --namespace=development --as=john

#kubectl auth can-i create pods --namespace=development --as=john

#kubectl auth can-i get pods --namespace=development --as=john

#kubectl auth can-i delete pods --namespace=development --as=john

Create pod and service

#kubectl run --generator=run-pod/v1 nginx-resolver --image=nginx

#kubectl describe pod nginx-resolver

#kubectl expose pod nginx-resolver --name=nginx-resolver-service --port=80 --target-port=80 --type=ClusterIP

#kubectl describe svc nginx-resolver-service

#kubectl get pod nginx-resolver -o wide

#kubectl get svc

#kubectl run --generator=run-pod/v1 test-nslookup --image=busybox:1.28 --rm -it -- nslookup nginx-resolver-service > /root/nginx.svc

#cat /root/nginx.svc

#kubectl run --generator=run-pod/v1 test-nslookup --image=busybox:1.28 -rm -it -- nslookup 10-32-0-5.default.pod > /root/nginx.pod

#cat /root/nginx.pod

Create static pod on node01

#kubectl get node

#ssh node01

#systemctl status kubelet

#cd /var/lib/kubelet 

#less config.yaml --> find out the static pod path

#cd /etc/kubernetes/manifest

#exit --> go back to master

#kubectl run --generator=run-pod/v1 nginx-critical --image=nginx --dry-run -o yaml > nginx-critical.yaml

#ssh node01

#cd /etc/kubernetes/manifests

#vi nginx-critical.yaml

#docker ps |grep -i nginx-critical

#exit

#kubectl get pods -o wide