Kubernetes使用StorageClass动态生成NFS类型的PV

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1、什么是StorageClass

StorageClass对象会定义下面两部分内容:

• 1: PV的属性.比如,存储类型,Volume的大小等.
• 2: 创建这种PV需要用到的存储插件

有了这两个信息之后，Kubernetes就能够根据用户提交的PVC，找到一个对应的StorageClass，之后Kubernetes就会调用该StorageClass声明的存储插件，进而创建出需要的PV。 但是其实使用起来是一件很简单的事情,你只需要根据自己的需求，编写YAML文件即可，然后使用kubectl create命令执行即可

2、流程

1. 创建一个可用的NFS Serve
2. 创建Service Account.这是用来管控NFS provisioner在k8s集群中运行的权限
3. 创建StorageClass.负责建立PVC并调用NFS provisioner进行预定的工作,并让PV与PVC建立管理
4. 创建NFS provisioner.有两个功能,一个是在NFS共享目录下创建挂载点(volume),另一个则是建了PV并将PV与NFS的挂载点建立关联

3、创建StorageClass

3.1、创建NFS共享服务

[root@nfs nfsdata]# yum install -y nfs-utils
[root@nfs nfsdata]# mkdir /nfsdata
[root@nfs nfsdata]# chmod 755 /nfsdata
[root@nfs nfsdata]# chown nfsnobody:nfsnobody /nfsdata/
[root@nfs nfsdata]# echo "/nfsdata    *(rw,sync,all_squash)" > /etc/exports
[root@nfs nfsdata]# systemctl enable nfs
[root@nfs nfsdata]# systemctl start nfs
[root@nfs nfsdata]# exportfs -rv
exporting *:/nfsdata

3.2、创建account及相关权限

nfs-rbac.yaml

apiVersion: v1
kind: ServiceAccount
metadata:
  name: nfs-provisioner
 # replace with namespace where provisioner is deployed
  namespace: nfs-provisioner #根据实际环境设定namespace,下面类同
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: nfs-provisioner-runner
rules:
- apiGroups: [""]
  resources: ["persistentvolumes"]
  verbs: ["get", "list", "watch", "create", "delete"]
- apiGroups: [""]
  resources: ["persistentvolumeclaims"]
  verbs: ["get", "list", "watch", "update"]
- apiGroups: ["storage.k8s.io"]
  resources: ["storageclasses"]
  verbs: ["get", "list", "watch"]
- apiGroups: [""]
  resources: ["events"]
  verbs: ["create", "update", "patch"]
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: run-nfs-provisioner
subjects:
- kind: ServiceAccount
  name: nfs-provisioner
   # replace with namespace where provisioner is deployed
  namespace: nfs-provisioner
roleRef:
kind: ClusterRole
name: nfs-provisioner-runner
apiGroup: rbac.authorization.k8s.io
---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: leader-locking-nfs-provisioner
  # replace with namespace where provisioner is deployed
  namespace: nfs-provisioner
rules:
- apiGroups: [""]
  resources: ["endpoints"]
  verbs: ["get", "list", "watch", "create", "update", "patch"]
---
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: leader-locking-nfs-provisioner
subjects:
- kind: ServiceAccount
  name: nfs-provisioner
   # replace with namespace where provisioner is deployed
  namespace: nfs-provisioner
roleRef:
kind: Role
name: leader-locking-nfs-provisioner
apiGroup: rbac.authorization.k8s.io

3.3、创建NFS资源的StorageClass

nfs-storageclass.yaml

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: nfs
provisioner: example.com/nfs #这里的名称要和provisioner配置文件中的环境变量PROVISIONER_NAME保持一致

3.4、创建NFS provisioner Deployment

nfs-deployment.yaml

kind: Deployment
apiVersion: apps/v1
metadata:
  name: nfs-provisioner
  namespace: nfs-provisioner
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nfs-provisioner
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: nfs-provisioner
    spec:
      serviceAccount: nfs-provisioner
      containers:
        - name: nfs-provisioner
          image: registry.cn-hangzhou.aliyuncs.com/open-ali/nfs-client-provisioner
          volumeMounts:
            - name: nfs-client-root
              mountPath: /persistentvolumes
          env:
            - name: PROVISIONER_NAME
              value: example.com/nfs #provisioner名称,请确保该名称与 nfs-StorageClass.yaml文件中的provisioner名称保持一致
            - name: NFS_SERVER
              value: 172.20.2.10 #NFS Server IP地址
            - name: NFS_PATH
              value: /nfsdata #NFS挂载卷
    volumes:
      - name: nfs-client-root
        nfs:
          server: 172.20.2.10 #NFS Server IP地址
          path: /nfsdata #NFS挂载卷

[root@kubernetes-master nfs]# ll
total 20
-rw-r--r-- 1 root root  894 Dec  9 13:55 nfs-deployment.yaml
-rw-r--r-- 1 root root   65 Dec  9 14:50 nfs-namespace.yaml
-rw-r--r-- 1 root root 1449 Dec  9 15:15 nfs-rbac.yaml
-rw-r--r-- 1 root root  100 Dec  9 14:18 nfs-storageclass.yaml

4、创建Pod，检测部署

pvc-nfs.yaml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-nfs
spec:
accessModes:
   - ReadWriteOnce
storageClassName: nfs
resources:
  requests:
    storage: 1Gi

[root@kubernetes-master nfs]# kubectl apply -f pvc-nfs.yaml 
persistentvolumeclaim/pvc-nfs created
[root@kubernetes-master nfs]# kubectl get pvc
NAME      STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
pvc-nfs   Bound    pvc-7461b40b-f52e-4bf6-9d73-40432b77f108   1Gi        RWO            nfs            1s

创建测试pod,查看是否可以正常挂载

kind: Pod
apiVersion: v1
metadata:
 name: test-pod
spec:
 containers:
 - name: test-pod
   image: busybox:1.24
   command:
     - "/bin/sh"
   args:
     - "-c"
     - "touch /mnt/SUCCESS && exit 0 || exit 1"   #创建一个SUCCESS文件后退出
   volumeMounts:
     - name: pvc-nfs
       mountPath: "/mnt"
 restartPolicy: "Never"
 volumes:
   - name: pvc-nfs
     persistentVolumeClaim:
       claimName: pvc-nfs #与PVC名称保持一致

[root@nfs nfsdata]# ll default-pvc-nfs-pvc-7461b40b-f52e-4bf6-9d73-40432b77f108/
total 0
-rw-r--r-- 1 nfsnobody nfsnobody 0 Dec  9 15:29 SUCCESS #下面有一个 SUCCESS 的文件，证明我们上面的验证是成功