kubernetes搭建 十五、持久化数据卷PV

PersistenVolume（PV，持久卷）：对存储抽象实现，使得存储作为集群中的资源。
PersistenVolumeClaim（PVC，持久卷申请）：PVC消费PV的资源
Pod申请PVC作为卷来使用，集群通过PVC查找绑定的PV，并Mount给Pod。

一、创建nfs pv

1、PV空间被释放时的处理机制指定为Recycle，空间回收，在删除PV后，会删除存储卷下所有文件。默认为机制Retain，保持不动，由管理员手动回收。
vim nfs-pv.yaml

[root@k8s-master-101 volume]# cat nfs-pv.yaml 
apiVersion: v1
kind: PersistentVolume
metadata:
  name: nfs-pv
  labels:
    release: "nfs"
spec:
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Recycle
  nfs:
    path: /opt/nfs/data
    server: 10.0.0.31

2、spec里可以定义标签选择器来挑选要绑定的PV，例如这个pvc绑定上面pv的标签release: “nfs”，也可以匹配条件，比如accessModes storage
vim nfs-pvc.yaml

[root@k8s-master-101 volume]# cat nfs-pvc.yaml 
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc001
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 5Gi
  selector:
    matchLabels:
      release: "nfs"

3、创建pv和pvc

[root@k8s-master-101 volume]# kubectl create -f nfs-pv.yaml
persistentvolume/nfs-pv created
[root@k8s-master-101 volume]# kubectl create -f nfs-pvc.yaml
persistentvolumeclaim/pvc001 created

4、查看pv和pvc，可以看到pvc001绑定了nfs-pv

[root@k8s-master-101 volume]# kubectl get pv,pvc
NAME                      CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM            STORAGECLASS   REASON   AGE
persistentvolume/nfs-pv   5Gi        RWX            Recycle          Bound    default/pvc001                           51s

NAME                           STATUS   VOLUME   CAPACITY   ACCESS MODES   STORAGECLASS   AGE
persistentvolumeclaim/pvc001   Bound    nfs-pv   5Gi        RWX                           48s

5、创建容器进行测试，指定数据卷为刚才创建的pvc001
vim nfspvc-deployment.yaml

[root@k8s-master-101 volume]# cat nfspvc-deployment.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 3
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        volumeMounts:
        - name: wwwroot
          mountPath: /usr/share/nginx/html
        ports:
        - containerPort: 80
      volumes:
        - name: wwwroot
          persistentVolumeClaim:
            claimName: pvc001

6、创建并进入容器查看是否挂载成功，可以看到已经挂载上去了。事先确认一下nfs服务器被挂载的目录/opt/nfs/data下有没有index.html文件，没有就创建一个来测试。

[root@k8s-master-101 volume]# kubectl create -f nfs-deployment.yaml
deployment.extensions/nginx-deployment created
[root@k8s-master-101 volume]# kubectl get pod
NAME                                READY   STATUS    RESTARTS   AGE
nginx-deployment-577c68c7f5-2bjxp   1/1     Running   0          19s
nginx-deployment-577c68c7f5-866fr   1/1     Running   0          19s
nginx-deployment-577c68c7f5-wg5bb   1/1     Running   0          19s

[root@k8s-master-101 volume]# kubectl exec -it nginx-deployment-577c68c7f5-2bjxp bash
root@nginx-deployment-577c68c7f5-2bjxp:/# cat /usr/share/nginx/html/index.html 
nfs数据卷挂载成功！

7、使用了PV后，可以把nfs或glusterfs等网络文件系统事先创建PV数据卷，然后用pvc关联起来，在使用的时候直接指定pvc即可，这样可以省去指定网络存储IP和地址的麻烦。

二、创建glusterfs pv

1、创建一个和前面相似的给gluster用的pv，指定标签，然后指定glusterfs里的endpoints为前面创建的glusterfs-cluster，path数据卷为gv0
vim gluster-pv.yaml

[root@k8s-master-101 volume]# cat gluster-pv.yaml 
apiVersion: v1
kind: PersistentVolume
metadata:
  name: gluster-pv
  labels:
    release: "gluster"
spec:
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteMany
  glusterfs:
    endpoints: "glusterfs-cluster"
    path: "gv0"
    readOnly: false

2、vim gluster-pvc.yaml

[root@k8s-master-101 volume]# cat gluster-pvc.yaml      
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc002
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 5Gi
  selector:
    matchLabels:
      release: "gluster"

3、创建pv和pvc并查看

[root@k8s-master-101 volume]# kubectl create -f gluster-pv.yaml
persistentvolume/gluster-pv created
[root@k8s-master-101 volume]# kubectl create -f gluster-pvc.yaml
persistentvolumeclaim/pvc002 created
[root@k8s-master-101 volume]# kubectl get pv,pvc
NAME                          CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM            STORAGECLASS   REASON   AGE
persistentvolume/gluster-pv   5Gi        RWX            Retain           Bound    default/pvc002                           12s
persistentvolume/nfs-pv       5Gi        RWX            Recycle          Bound    default/pvc001                           20m

NAME                           STATUS   VOLUME       CAPACITY   ACCESS MODES   STORAGECLASS   AGE
persistentvolumeclaim/pvc001   Bound    nfs-pv       5Gi        RWX                           20m
persistentvolumeclaim/pvc002   Bound    gluster-pv   5Gi        RWX                           9s

4、创建一个glusterfs的deployment来测试，内容和前面nfs的pod一样，只需要把数据卷改成pvc002就可以了
vim glusterpvc-deployment.yaml

[root@k8s-master-101 volume]# cat glusterpvc-deployment.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 3
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        volumeMounts:
        - name: wwwroot
          mountPath: /usr/share/nginx/html
        ports:
        - containerPort: 80
      volumes:
        - name: wwwroot
          persistentVolumeClaim:
            claimName: pvc002

5、删除前面的nfs创建的deployment，然后重新创建一个来测试glusterfs，进入容器查看

[root@k8s-master-101 volume]#  kubectl delete -f nfs-deployment.yaml       
deployment.extensions "nginx-deployment" deleted
[root@k8s-master-101 volume]# kubectl create -f glusterpvc-deployment.yaml
deployment.extensions/nginx-deployment created
[root@k8s-master-101 volume]# kubectl get pod
NAME                               READY   STATUS    RESTARTS   AGE
nginx-deployment-f996c7445-fn6w4   1/1     Running   0          66s
nginx-deployment-f996c7445-mcgjm   1/1     Running   0          66s
nginx-deployment-f996c7445-zt24m   1/1     Running   0          66s

[root@k8s-master-101 volume]# kubectl exec -it nginx-deployment-f996c7445-fn6w4 bash
root@nginx-deployment-f996c7445-fn6w4:/# cat /usr/share/nginx/html/index.html 
glusterfs挂载成功！