k8s持久化存储的第三节，给大家带来 StorageClass动态存储 的讲解。

我们上节课提到了K8s对于存储解耦的设计是，pv交给存储管理员来管理，我们只管用pvc来消费就好，但这里我们实际还是得一起管理pv和pvc，在实际工作中，我们（存储管理员）可以提前配置好pv的动态供给StorageClass，来根据pvc的消费动态生成pv。

StorageClass

我这是直接拿生产中用的实例来作演示，利用nfs-client-provisioner来生成一个基于nfs的StorageClass，部署配置yaml配置如下，保持为nfs-sc.yaml：

apiVersion: v1
kind: ServiceAccount
metadata:
  name: nfs-client-provisioner
  namespace: kube-system

---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: nfs-client-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: ["list", "watch", "create", "update", "patch"]
  - apiGroups: [""]
    resources: ["endpoints"]
    verbs: ["get", "list", "watch", "create", "update", "patch"]

---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: run-nfs-client-provisioner
subjects:
  - kind: ServiceAccount
    name: nfs-client-provisioner
    namespace: kube-system 
roleRef:
  kind: ClusterRole
  name: nfs-client-provisioner-runner
  apiGroup: rbac.authorization.k8s.io

---
kind: Deployment
apiVersion: apps/v1
metadata:
  name: nfs-provisioner-01
  namespace: kube-system
spec:
  replicas: 1
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app: nfs-provisioner-01
  template:
    metadata:
      labels:
        app: nfs-provisioner-01
    spec:
      serviceAccountName: nfs-client-provisioner
      containers:
        - name: nfs-client-provisioner
          image: jmgao1983/nfs-client-provisioner:latest
          imagePullPolicy: IfNotPresent
          volumeMounts:
            - name: nfs-client-root
              mountPath: /persistentvolumes
          env:
            - name: PROVISIONER_NAME
              value: nfs-provisioner-01  # 此处供应者名字供storageclass调用
            - name: NFS_SERVER
              value: 10.0.1.201   # 填入NFS的地址
            - name: NFS_PATH
              value: /nfs_dir   # 填入NFS挂载的目录
      volumes:
        - name: nfs-client-root
          nfs:
            server: 10.0.1.201   # 填入NFS的地址
            path: /nfs_dir   # 填入NFS挂载的目录

---
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: nfs-boge
provisioner: nfs-provisioner-01
# Supported policies: Delete、 Retain ， default is Delete
reclaimPolicy: Retain

开始创建这个StorageClass：

# kubectl apply -f nfs-sc.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
deployment.apps/nfs-provisioner-01 created
  orageclass.storage.k8s.io/nfs-boge created

# 注意这个是在放kube-system的namespace下面，这里面放置一些偏系统类的服务
# kubectl -n kube-system get pod -w
NAME                                       READY   STATUS              RESTARTS   AGE
calico-kube-controllers-7fdc86d8ff-dpdm5   1/1     Running             1          24h
calico-node-8jcp5                          1/1     Running             1          24h
calico-node-m92rn                          1/1     Running             1          24h
calico-node-xg5n4                          1/1     Running             1          24h
calico-node-xrfqq                          1/1     Running             1          24h
coredns-d9b6857b5-5zwgf                    1/1     Running             1          24h
metrics-server-869ffc99cd-wfj44            1/1     Running             2          24h
nfs-provisioner-01-5db96d9cc9-qxlgk        0/1     ContainerCreating   0          9s
nfs-provisioner-01-5db96d9cc9-qxlgk        1/1     Running             0          21s

# StorageClass已经创建好了
# kubectl get sc
NAME       PROVISIONER          RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
nfs-boge   nfs-provisioner-01   Retain          Immediate           false                  37s

我们来基于StorageClass创建一个pvc，看看动态生成的pv是什么效果：

# vim pvc-sc.yaml 
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: pvc-sc
spec:
  storageClassName: nfs-boge
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 1Mi

# kubectl  apply -f pvc-sc.yaml 
persistentvolumeclaim/pvc-sc created

# kubectl  get pvc
NAME     STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
pvc-sc   Bound    pvc-63eee4c7-90fd-4c7e-abf9-d803c3204623   1Mi        RWX            nfs-boge       3s
pvc1     Bound    pv1                                        1Gi        RWO            nfs            24m

# kubectl  get pv
NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM            STORAGECLASS   REASON   AGE
pv1                                        1Gi        RWO            Recycle          Bound    default/pvc1     nfs                     49m
pvc-63eee4c7-90fd-4c7e-abf9-d803c3204623   1Mi        RWX            Retain           Bound    default/pvc-sc   nfs-boge                7s

我们修改下nginx的yaml配置，将pvc的名称换成上面的pvc-sc：

# vim nginx.yaml 
---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: nginx
  name: nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - image: nginx
        name: nginx
        volumeMounts:    # 我们这里将nginx容器默认的页面目录挂载
          - name: html-files
            mountPath: "/usr/share/nginx/html"
      volumes:
        - name: html-files
          persistentVolumeClaim:
            claimName: pvc-sc


# kubectl apply -f nginx.yaml 
service/nginx unchanged
deployment.apps/nginx configured

# 这里注意下，因为是动态生成的pv，所以它的目录基于是一串随机字符串生成的，这时我们直接进到pod内来创建访问页面
# kubectl exec -it nginx-57cdc6d9b4-n497g -- bash
root@nginx-57cdc6d9b4-n497g:/# echo 'storageClass used' > /usr/share/nginx/html/index.html
root@nginx-57cdc6d9b4-n497g:/# exit

# curl 10.68.238.54                              
storageClass used

# 我们看下NFS挂载的目录
# ll /nfs_dir/
total 0
drwxrwxrwx 2 root root 24 Nov 27 17:52 default-pvc-sc-pvc-63eee4c7-90fd-4c7e-abf9-d803c3204623
drwxr-xr-x 2 root root  6 Nov 27 17:25 pv1