[kubernetes-실습] PV 와 PVC 생성

# NFS Server/Client 세팅

# NFS Server/Client 세팅

# ----------------------------------
# master node : NFS Server
# worker node : NFS Client
# ----------------------------------
# master node : NFS Server 세팅
ps0107@k8smaster1:~$ sudo apt-get update && sudo apt-get install -y nfs-kernel-server
ps0107@k8smaster1:~$ sudo mkdir /opt/sfw
ps0107@k8smaster1:~$ sudo chmod 1777 /opt/sfw
ps0107@k8smaster1:~$ sudo bash -c 'echo software > /opt/sfw/hello.txt'
ps0107@k8smaster1:~$
ps0107@k8smaster1:~$ sudo vi /etc/exports
ps0107@k8smaster1:~$ cat /etc/exports
/opt/sfw/	*(rw,sync,no_root_squash,subtree_check)
ps0107@k8smaster1:~$ sudo exportfs -ra

# worker node : NFS Client 세팅
ps0107@k8sworker1:~$ sudo apt-get -y install nfs-common
ps0107@k8sworker1:~$ showmount -e k8smaster
Export list for k8smaster:
/opt/sfw *
ps0107@k8sworker1:~$ sudo mount k8smaster:/opt/sfw /mnt
ps0107@k8sworker1:~$ ls -l /mnt
total 4
-rw-r--r-- 1 root root 9 Feb  3 14:12 hello.txt

---

# Creating a Persistent NFS Volume (PV)

# PV 생성을 위한 yaml 파일 생성
ps0107@k8smaster1:~$ cat PVol.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
  name: pvvol-1
spec:
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain
  nfs:
    path: /opt/sfw
    server: k8smaster
    readOnly: false

# PV 생성
ps0107@k8smaster1:~$ kubectl create -f PVol.yaml
persistentvolume/pvvol-1 created

# PV 생성 확인
ps0107@k8smaster1:~$ kubectl get pv
NAME      CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS   REASON   AGE
pvvol-1   1Gi        RWX            Retain           Available                                   7s

---

# Creating a Persistent Volume Claim (PVC)

# pvc 리소스 확인. 현재는 아무것도 없음.
ps0107@k8smaster1:~$ kubectl get pvc
No resources found.

# pvc 생성을 위한 yaml 파일 생성
# pvc 200Mi 요청
ps0107@k8smaster1:~$ vi pvc.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-one
spec:
  accessModes:
  - ReadWriteMany
  resources:
     requests:
       storage: 200Mi

# pvc 생성
ps0107@k8smaster1:~$ kubectl create -f pvc.yaml
persistentvolumeclaim/pvc-one created

# pvc-one Bound 상태 확인
ps0107@k8smaster1:~$ kubectl get pvc
NAME      STATUS   VOLUME    CAPACITY   ACCESS MODES   STORAGECLASS   AGE
pvc-one   Bound    pvvol-1   1Gi        RWX                           7s

# pvvol-1 이 CLAIM 에 보면 pvc-one 에 할당됨을 확인 가능
ps0107@k8smaster1:~$ kubectl  get pv
NAME      CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM             STORAGECLASS   REASON   AGE
pvvol-1   1Gi        RWX            Retain           Bound    default/pvc-one                           9m6s

# 실제 pvc를 사용하기 위해 새로운 deployment를 생성해 보자.
ps0107@k8smaster1:~$ vi nfs-pod.yaml
apiVersion: apps/v1beta1
kind: Deployment
metadata:
  annotations:
    deployment.kubernetes.io/revision: "1"
  generation: 1
  labels:
    run: nginx
  name: nginx-nfs
  namespace: default
  resourceVersion: "1411"
spec:
  replicas: 1
  selector:
    matchLabels:
      run: nginx
  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 1
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        run: nginx
    spec:
      containers:
      - image: nginx
        imagePullPolicy: Always
        name: nginx
        volumeMounts:
        - name: nfs-vol
          mountPath: /opt
        ports:
        - containerPort: 80
          protocol: TCP
        resources: {}
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
      volumes:                           # <- volumes 설정
      - name: nfs-vol
        persistentVolumeClaim:
          claimName: pvc-one
      dnsPolicy: ClusterFirst
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      terminationGracePeriodSeconds: 30

# deployment 생성
ps0107@k8smaster1:~$ kubectl create -f nfs-pod.yaml
deployment.apps/nginx-nfs created

# pod 생성 확인
ps0107@k8smaster1:~$ kubectl get pods
NAME                         READY   STATUS    RESTARTS   AGE
ds-one-65r2h                 1/1     Running   0          11h
ds-one-hpx96                 1/1     Running   0          11h
nginx-nfs-86845f4d55-fxqkt   1/1     Running   0          5s

# 생성된 pod에 mount, volume 확인
ps0107@k8smaster1:~$ kubectl describe pod nginx-nfs-86845f4d55-fxqkt
Name:           nginx-nfs-86845f4d55-fxqkt
Namespace:      default
Priority:       0
Node:           k8sworker1/10.146.0.4
Start Time:     Mon, 03 Feb 2020 14:51:15 +0000
Labels:         pod-template-hash=86845f4d55
                run=nginx
Annotations:    cni.projectcalico.org/podIP: 192.168.1.84/32
Status:         Running
IP:             192.168.1.84
Controlled By:  ReplicaSet/nginx-nfs-86845f4d55
Containers:
  nginx:
    Container ID:   docker://e3eb8a022421675c8a323dea8c1c4b6eb9a5f2b060f4231cd587a6bd821c7ff1
    Image:          nginx
    Image ID:       docker-pullable://nginx@sha256:ad5552c786f128e389a0263104ae39f3d3c7895579d45ae716f528185b36bc6f
    Port:           80/TCP
    Host Port:      0/TCP
    State:          Running
      Started:      Mon, 03 Feb 2020 14:51:19 +0000
    Ready:          True
    Restart Count:  0
    Environment:    <none>
    Mounts:
      /opt from nfs-vol (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-76w5h (ro)
Conditions:
  Type              Status
  Initialized       True
  Ready             True
  ContainersReady   True
  PodScheduled      True
Volumes:
  nfs-vol:
    Type:       PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
    ClaimName:  pvc-one
    ReadOnly:   false
  default-token-76w5h:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  default-token-76w5h
    Optional:    false
QoS Class:       BestEffort
Node-Selectors:  <none>
Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s
                 node.kubernetes.io/unreachable:NoExecute for 300s
Events:
  Type    Reason     Age   From                 Message
  ----    ------     ----  ----                 -------
  Normal  Scheduled  22s   default-scheduler    Successfully assigned default/nginx-nfs-86845f4d55-fxqkt to k8sworker1
  Normal  Pulling    21s   kubelet, k8sworker1  Pulling image "nginx"
  Normal  Pulled     18s   kubelet, k8sworker1  Successfully pulled image "nginx"
  Normal  Created    18s   kubelet, k8sworker1  Created container nginx
  Normal  Started    18s   kubelet, k8sworker1  Started container nginx

# pvc 상태를 확인 해본다. 정상적으로 bound 되었는지 확인 가능
ps0107@k8smaster1:~$ kubectl get pvc
NAME      STATUS   VOLUME    CAPACITY   ACCESS MODES   STORAGECLASS   AGE
pvc-one   Bound    pvvol-1   1Gi        RWX                           2m7s