Exercise 5.1: Configure the Deployment: ConfigMaps

1. CP 노드에 연결된 터미널로 이동

2. ConfigMap에 사용할 파일 생성

   {
       cd && mkdir primary
       echo c > primary/cyan
       echo m > primary/magenta
       echo y > primary/yellow
       echo k > primary/black
       echo "known as key" >> primary/black
       echo blue > favorite
   }

3. ConfigMap 생성

   kubectl create configmap colors \
   --from-literal=text=black \
   --from-file=./favorite \
   --from-file=./primary/

4. 생성된 ConfigMap 확인

   kubectl get cm colors

5. 생성된 ConfigMap 데이터 확인

   kubectl get cm colors -o yaml 

6. Pod 생성

   cat <<EOF | kubectl create -f -
   apiVersion: v1
   kind: Pod
   metadata:
     name: shell-demo
   spec:
     containers:
     - name: nginx
       image: nginx
       env:
       - name: ilike
         valueFrom:
           configMapKeyRef:
             name: colors
             key: favorite
   EOF

7. 생성된 Pod에 지정한 환경변수 확인

   kubectl exec shell-demo -- /bin/bash -c 'echo $ilike'

8. Pod 삭제

   kubectl delete pod shell-demo

9. Pod 생성

   cat <<EOF | kubectl create -f -
   apiVersion: v1
   kind: Pod
   metadata:
     name: shell-demo
   spec:
     containers:
     - name: nginx
       image: nginx
       envFrom:
       - configMapRef:
           name: colors
   EOF

10. 생성된 Pod에 지정된 모든 환경변수 확인

    kubectl exec shell-demo -- /bin/bash -c 'env'

11. Pod 삭제

    kubectl delete pod shell-demo

12. ConfigMap 생성

    cat <<EOF | kubectl create -f -
    apiVersion: v1
    kind: ConfigMap
    metadata:
      name: fast-car
      namespace: default
    data:
      car.make: Ford
      car.model: Mustang
      car.trim: Shelby
    EOF

13. 생성된 ConfigMap 데이터 확인

    kubectl get cm fast-car -o yaml 

14. Pod 생성

    cat <<EOF | kubectl create -f -
    apiVersion: v1
    kind: Pod
    metadata:
      name: shell-demo
    spec:
      containers:
      - name: nginx
        image: nginx
        volumeMounts:
          - name: car-vol
            mountPath: /etc/cars
      volumes:
        - name: car-vol
          configMap:
            name: fast-car
    EOF

15. 생성된 Pod에 ConfigMap의 데이터가 볼륨으로 마운트 되었는지 확인

    kubectl exec shell-demo -- ls /etc/cars

16. 생성된 Pod에 마운트된 파일 내용 확인

    kubectl exec shell-demo -- /bin/bash -c 'cat /etc/cars/car.trim; echo'

17. Pod 삭제

    kubectl delete pod shell-demo

18. Readiness Probe를 명시하고 Pod 생성

    cat <<EOF | kubectl apply -f -
    apiVersion: v1
    kind: Pod
    metadata:
      name: shell-demo
    spec:
      containers:
      - name: nginx
        image: nginx
        volumeMounts:
        - name: car-vol
          mountPath: /etc/cars
        readinessProbe:
          exec:
            command:
            - ls
            - /etc/cars
          periodSeconds: 5
      volumes:
        - name: car-vol
          configMap:
            name: fast-car
    EOF

19. Pod 상태 확인

    kubectl get pod shell-demo

20. 리소스 삭제

    {
        kubectl delete pod shell-demo
        kubectl delete cm fast-car colors
    }