一、nfs-client-provisioner简介

Kubernetes集群中NFS类型的存储没有内置 Provisioner。但是你可以在集群中为NFS配置外部Provisioner。

Nfs-client-provisioner是一个开源的NFS 外部Provisioner，利用NFS Server为Kubernetes集群提供持久化存储，并且支持动态购买PV。但是nfs-client-provisioner本身不提供NFS，需要现有的NFS服务器提供存储。持久卷目录的命名规则为:$namespace-${pvcName}-${pvName}。

K8S的外部NFS驱动可以按照其工作方式（是作为NFS server还是NFS client）分为两类：

nfs-client:

它通过K8S内置的NFS驱动挂载远端的NFS服务器到本地目录；然后将自身作为storage provider关联storage class。当用户创建对应的PVC来申请PV时，该provider就将PVC的要求与自身的属性比较，一旦满足就在本地挂载好的NFS目录中创建PV所属的子目录，为Pod提供动态的存储服务。

nfs-server:

与nfs-client不同，该驱动并不使用k8s的NFS驱动来挂载远端的NFS到本地再分配，而是直接将本地文件映射到容器内部，然后在容器内使用ganesha.nfsd来对外提供NFS服务；在每次创建PV的时候，直接在本地的NFS根目录中创建对应文件夹，并export出该子目录。

本文将介绍使用nfs-client-provisioner这个应用，利用NFS Server给Kubernetes作为持久存储的后端，并且动态提供PV。前提条件是有已经安装好的NFS服务器，并且NFS服务器与Kubernetes的Slave节点网络能够连通。将nfs-client驱动做为一个deployment部署到K8S集群中，然后对外提供存储服务

二、准备NFS服务端

2.0 当前环境信息

[root@master1 ~]# kubectl get nodes -owide
NAME               STATUS   ROLES    AGE     VERSION    INTERNAL-IP     EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION              CONTAINER-RUNTIME
master1.k8s.test   Ready    <none>   5d21h   v1.22.17   10.140.20.141   <none>        CentOS Linux 7 (Core)   6.3.2-1.el7.elrepo.x86_64   docker://19.3.15
master2.k8s.test   Ready    <none>   5d21h   v1.22.17   10.140.20.142   <none>        CentOS Linux 7 (Core)   6.3.2-1.el7.elrepo.x86_64   docker://19.3.15
master3.k8s.test   Ready    <none>   5d21h   v1.22.17   10.140.20.143   <none>        CentOS Linux 7 (Core)   6.3.2-1.el7.elrepo.x86_64   docker://19.3.15
node1.k8s.test     Ready    <none>   5d21h   v1.22.17   10.140.20.156   <none>        CentOS Linux 7 (Core)   6.3.2-1.el7.elrepo.x86_64   docker://19.3.15

2.1 通过yum安装nfs server端

[root@master1 ~]# rpm -qa|egrep "nfs|rpc"
[root@master1 ~]# yum -y install nfs-utils rpcbind

2.2 启动服务和设置开机启动

#启动nfs-server，并加入开机启动
[root@master1 ~]# systemctl start rpcbind.service
[root@master1 ~]# systemctl enable rpcbind.service
[root@master1 ~]# systemctl start nfs
[root@master1 ~]# systemctl enable nfs-server --now
#查看nfs server是否已经正常启动
[root@master1 ~]# systemctl status nfs-server

2.3 编辑配置文件，设置共享目录

[root@master1 ~]# mkdir /data/nfs-provisioner -p
[root@master1 ~]# cat > /etc/exports <<EOF
/data/nfs_provisioner   10.140.20.0/24(rw,no_root_squash)
EOF

#不用重启nfs服务,配置文件就会生效

[root@master1 ~]# exportfs -arv 
exporting 10.140.20.0/24:/data/nfs_provisioner

用于配置NFS服务程序配置文件的参数：

参数	含义
ro	只读
rw	读写
root_squash	当NFS客户端以root管理员访问时，映射未NFS服务器的匿名用户
no_root_squash	当NFS客户端以root管理员访问时，映射未NFS服务器的root管理员
all_suash	无论NFS客户端使用什么账户访问，均映射未NFS服务器的匿名用户
sync	同时将数据写入到内存与硬盘中，保证不丢失数据
async	优先将数据保存到内存，然后再写入硬盘。效率高但易丢失数据

2.4 客户端测试

客户端需要安装nfs-utils

[root@master1 ~]# yum -y install nfs-utils
[root@master1 ~]# systemctl enable nfs --now
[root@master1 ~]# systemctl status nfs

客户端验证

[root@master2 ~]# showmount -e 10.140.20.141
Export list for 10.140.20.141:
/data/nfs_provisioner 10.140.20.0/24

三、部署nfs-provisioner

3.1.0 创建namespace、工作目录

[root@master1 ~]# kubectl create namespace test
[root@master1 ~]# mkdir  nfs-provisioner
[root@master1 ~]# cd  nfs-provisioner

3.1 创建ServiceAccount

[root@master1 ~]# cat > nfs-sa.yaml << EOF
apiVersion: v1
kind: ServiceAccount
metadata:
  name: nfs-client-provisioner
  # replace with namespace where provisioner is deployed
  namespace: test
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: nfs-client-provisioner-runner
rules:
  - apiGroups: [""]
    resources: ["nodes"]
    verbs: ["get", "list", "watch"]
  - 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-client-provisioner
subjects:
  - kind: ServiceAccount
    name: nfs-client-provisioner
    # replace with namespace where provisioner is deployed
    namespace: test
roleRef:
  kind: ClusterRole
  name: nfs-client-provisioner-runner
  apiGroup: rbac.authorization.k8s.io
---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: leader-locking-nfs-client-provisioner
  # replace with namespace where provisioner is deployed
  namespace: test
rules:
  - apiGroups: [""]
    resources: ["endpoints"]
    verbs: ["get", "list", "watch", "create", "update", "patch"]
---
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: leader-locking-nfs-client-provisioner
  # replace with namespace where provisioner is deployed
  namespace: test
subjects:
  - kind: ServiceAccount
    name: nfs-client-provisioner
    # replace with namespace where provisioner is deployed
    namespace: test
roleRef:
  kind: Role
  name: leader-locking-nfs-client-provisioner
  apiGroup: rbac.authorization.k8s.io
EOF

应用生效

[root@master1 nfs-provisioner]# kubectl apply -f nfs-sa.yaml
serviceaccount/nfs-client-provisioner created
clusterrole.rbac.authorization.k8s.io/nfs-client-provisioner-runner created
clusterrolebinding.rbac.authorization.k8s.io/run-nfs-client-provisioner created
role.rbac.authorization.k8s.io/leader-locking-nfs-client-provisioner created
rolebinding.rbac.authorization.k8s.io/leader-locking-nfs-client-provisioner created

3.2 创建Deployment

[root@master1 ~]# cat > nfs-deployment.yaml << EOF
kind: Deployment
apiVersion: apps/v1
metadata:
  name: nfs-client-provisioner
  namespace: test
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nfs-client-provisioner
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: nfs-client-provisioner
    spec:
      serviceAccountName: nfs-client-provisioner
      containers:
        - name: nfs-client-provisioner
          image: registry.cn-beijing.aliyuncs.com/mydlq/nfs-subdir-external-provisioner:v4.0.0
          volumeMounts:
            - name: nfs-client-root
              mountPath: /persistentvolumes
          env:
            - name: PROVISIONER_NAME
              value: nfs-provisioner # 和3.Storage中provisioner保持一致便可
            - name: NFS_SERVER
              value: 10.140.20.141
            - name: NFS_PATH
              value: /data/nfs_provisioner
      volumes:
        - name: nfs-client-root
          nfs:
            server: 10.140.20.141
            path: /data/nfs_provisioner
EOF

应用生效

[root@master1 nfs-provisioner]# kubectl apply -f nfs-deployment.yaml
deployment.apps/nfs-client-provisioner created

3.3 创建storageclass

[root@master1 ~]# cat > nfs-sc.yaml << EOF
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  annotations:
    storageclass.kubernetes.io/is-test-class: "true"
  name: nfs-storage
  namespace: test
provisioner: nfs-provisioner
volumeBindingMode: Immediate
reclaimPolicy: Delete
EOF

应用生效

[root@master1 nfs-provisioner]# kubectl apply -f nfs-sc.yaml
storageclass.storage.k8s.io/nfs-storage created

3.4 创建pvc

[root@master yaml]# cat > nfs-pvc.yaml << EOF
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: nfs-pvc
  namespace: test
  labels:
    app: nfs-pvc
spec:
  accessModes: #指定访问类型
  - ReadWriteOnce
  volumeMode: Filesystem #指定卷类型
  resources:
    requests:
      storage: 2Gi
  storageClassName: nfs-storage #指定创建的存储类的名字
EOF

#创建pvc
[root@master1 nfs-provisioner]# kubectl apply -n test -f nfs-pvc.yaml 
persistentvolumeclaim/nfs-pvc created
#查看pvc
[root@master1 nfs-provisioner]# kubectl get pvc -n test
NAME        STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
nfs-pvc     Bound    pvc-791dc175-c068-4977-a14b-02f8cb153bc3   2Gi        RWO            nfs-storage    8s
www-web-0   Bound    pvc-b666f81e-9723-4e88-8e81-157b9e081577   10Mi       RWO            nfs-storage    17m
www-web-1   Bound    pvc-a900806b-47e0-432e-81fd-865c5ff6e3ba   10Mi       RWO            nfs-storage    16m
#查看nfs共享目录
[root@master1 nfs-provisioner]# ls /data/nfs_provisioner/
test-nfs-pvc-pvc-791dc175-c068-4977-a14b-02f8cb153bc3
test-www-web-0-pvc-b666f81e-9723-4e88-8e81-157b9e081577
test-www-web-1-pvc-a900806b-47e0-432e-81fd-865c5ff6e3ba


#总结：创建pvc使使用storageclass，那么将会自动创建pv并进行绑定

四、创建应用测试动态添加PV

4.1 创建一个nginx应用

cat > nginx_sts_pvc.yaml << EOF
apiVersion: v1
kind: Service
metadata:
  name: nginx
  namespace: test
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    name: web
  clusterIP: None
  selector:
    app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
  namespace: test
spec:
  serviceName: "nginx"
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80
          name: web
        volumeMounts:
        - name: www
          mountPath: /usr/share/nginx/html
  volumeClaimTemplates:
  - metadata:
      name: www
    spec:
      accessModes: [ "ReadWriteOnce" ]
      storageClassName: "nfs-storage"  #使用新建的sc
      resources:
        requests:
          storage: 10Mi
EOF

应用生效

[root@master1 nfs-provisioner]# kubectl apply -f nginx_sts_pvc.yaml
service/nginx created
statefulset.apps/web created

4.2 检查结果

检查deployment、statefulset状态

[root@master1 nfs-provisioner]# kubectl get sts,deploy -n test
NAME                   READY   AGE
statefulset.apps/web   2/2     4m49s

NAME                                     READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/nfs-client-provisioner   1/1     1            1           15m

检查pod状态

[root@master1 nfs-provisioner]# kubectl get pods -n test
NAME                                     READY   STATUS    RESTARTS   AGE
nfs-client-provisioner-fb55999fb-pcrqt   1/1     Running   0          9m30s
web-0                                    1/1     Running   0          3m40s
web-1                                    1/1     Running   0          3m15s

检查nfs-server服务器是否创建pv持久卷：

[root@master1 nfs-provisioner]# kubectl get pvc,pv -n test
NAME                              STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
persistentvolumeclaim/nfs-pvc     Bound    pvc-791dc175-c068-4977-a14b-02f8cb153bc3   2Gi        RWO            nfs-storage    2m45s
persistentvolumeclaim/www-web-0   Bound    pvc-b666f81e-9723-4e88-8e81-157b9e081577   10Mi       RWO            nfs-storage    19m
persistentvolumeclaim/www-web-1   Bound    pvc-a900806b-47e0-432e-81fd-865c5ff6e3ba   10Mi       RWO            nfs-storage    19m

NAME                                                        CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM            STORAGECLASS   REASON   AGE
persistentvolume/pvc-791dc175-c068-4977-a14b-02f8cb153bc3   2Gi        RWO            Delete           Bound    test/nfs-pvc     nfs-storage             2m45s
persistentvolume/pvc-a900806b-47e0-432e-81fd-865c5ff6e3ba   10Mi       RWO            Delete           Bound    test/www-web-1   nfs-storage             19m
persistentvolume/pvc-b666f81e-9723-4e88-8e81-157b9e081577   10Mi       RWO            Delete           Bound    test/www-web-0   nfs-storage             19m


[root@master1 nfs-provisioner]# kubectl exec -it -n test web-0 bash
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
root@web-0:/# echo 1 >  /usr/share/nginx/html/1.txt
root@web-0:/# exit
[root@master1 nfs-provisioner]# ls /data/nfs_provisioner/
test-nfs-pvc-pvc-791dc175-c068-4977-a14b-02f8cb153bc3
test-www-web-0-pvc-b666f81e-9723-4e88-8e81-157b9e081577
test-www-web-1-pvc-a900806b-47e0-432e-81fd-865c5ff6e3ba
[root@master1 nfs-provisioner]# cat  /data/nfs_provisioner/test-www-web-0-pvc-b666f81e-9723-4e88-8e81-157b9e081577/1.txt 
1