[kubernetes]持久化存储之StorageClass

Posted 2022-04-01 运维少年

    熟悉了PV/PVC之后，我们知道PV和PVC是一一对应的，一旦PV被一个PVC关联之后，PV就不能被其他的PVC关联了。从这里可以看出，我们每使用一次PVC就要创建一次PV，有没有好的办法简化一些呢？有，那就是StorageClass(SC)，SC就好像是帮我们提供了一个存储池，当我们在这个存储池上创建PVC的时候，会自动创建PV，而且一个SC可以对应多个PVC，也就是说我们创建了一个SC后，就可以直接创建PVC了，不用再单独创建PV。

    在用户视图上就变成了这样：

    但实际上是这样的：

    

​01 创建StorageClass​

    因为StorageClass可以实现自动配置，所以使用StorageClass之前，我们需要先安装存储驱动的自动配置程序，而这个配置程序必须拥有一定的权限去访问我们的kubernetes集群（类似dashboard一样，必须有权限访问各种api，才能实现管理）。

    1）创建rbac

cat rbac.yaml 
apiVersion: v1
kind: ServiceAccount  # 创建一个用户
metadata:
  name: nfs-client-provisioner
  namespace: kube-system

---
kind: ClusterRole   # 创建一个集群角色
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: nfs-client-provisioner-runner
rules:  # 角色权限
  - 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  # 将用户绑定到集群角色中
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

# 应用
[root@host21 sc]# kubectl apply -f rbac.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

    2）创建自动配置程序 -- nfs-provisioner

[root@host21 sc]# cat dp.yaml 
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  # 用户名
      containers:
        - name: nfs-client-provisioner
          image: harbor.od.com/public/nfs-client-provisioner:latest
          imagePullPolicy: IfNotPresent
          volumeMounts:
            - name: nfs-client-root
              mountPath: /persistentvolumes
          env:  # 定义环境变量
            - name: PROVISIONER_NAME
              value: nfs-provisioner-01  # 此处供应者名字供storageclass调用
            - name: NFS_SERVER
              value: host200   # 填入NFS的地址
            - name: NFS_PATH
              value: /data/nfs-volume/sc-pool   # 填入NFS挂载的目录
      volumes:
        - name: nfs-client-root
          nfs:
            server: host200   # 填入NFS的地址
            path: /data/nfs-volume/sc-pool  # 填入NFS挂载的目录

# 应用
[root@host21 sc]# kubectl apply -f dp.yaml 
deployment.apps/nfs-provisioner-01 created

# 查看
[root@host21 sc]# kubectl get pod -n kube-system | grep nfs
nfs-provisioner-01-684f9b4798-lzbhv   1/1     Running   0          3m9s

    3）配置StorageClass

[root@host21 sc]# cat sc.yaml 
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: nfs-sc-pool
provisioner: nfs-provisioner-01  # 这里的名字要和dp里面定义的名字一样
# Supported policies: Delete、 Retain ， default is Delete
reclaimPolicy: Retain
# 应用
[root@host21 sc]# kubectl apply -f sc.yaml 
storageclass.storage.k8s.io/nfs-sc-pool created
# 查看
[root@host21 sc]# kubectl get sc
NAME          PROVISIONER          AGE
nfs-sc-pool   nfs-provisioner-01   14s

02 测试

    1）创建PVC

# pvc.yaml
[root@host21 sc]# cat pvc.yaml 
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: pvc01-sc-pool
spec:
  storageClassName: nfs-sc-pool  # 指定storageclass
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 1Mi
# 应用
[root@host21 sc]# kubectl apply -f pvc.yaml 
persistentvolumeclaim/pvc01-sc-pool created
# 查看pvc
[root@host21 sc]# kubectl get pvc 
NAME            STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
pvc01-sc-pool   Bound    pvc-e6d1021e-0db8-4dee-8149-4229c272e203   1Mi        RWX            nfs-sc-pool    5s
# 查看pv
[root@host21 sc]# kubectl get pv
NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                   STORAGECLASS   REASON   AGE
pvc-e6d1021e-0db8-4dee-8149-4229c272e203   1Mi        RWX            Retain           Bound    default/pvc01-sc-pool   nfs-sc-pool             8s

    通过上面可以看出我们创建了storageclass之后，就可以不用创建pv而直接创建pvc了。

    2）查看pv

[root@host21 sc]# kubectl describe pv pvc-e6d1021e-0db8-4dee-8149-4229c272e203 
Name:            pvc-e6d1021e-0db8-4dee-8149-4229c272e203
Labels:          <none>
Annotations:     pv.kubernetes.io/provisioned-by: nfs-provisioner-01
Finalizers:      [kubernetes.io/pv-protection]
StorageClass:    nfs-sc-pool
Status:          Bound
Claim:           default/pvc01-sc-pool
Reclaim Policy:  Retain
Access Modes:    RWX
VolumeMode:      Filesystem
Capacity:        1Mi
Node Affinity:   <none>
Message:         
Source:
    Type:      NFS (an NFS mount that lasts the lifetime of a pod)
    Server:    host200
    Path:      /data/nfs-volume/sc-pool/default-pvc01-sc-pool-pvc-e6d1021e-0db8-4dee-8149-4229c272e203
    ReadOnly:  false
Events:        <none>

    可以看到，pv自动被自动创建后，还在nfs目录中自动创建了一个和pv名称一样的目录给该pv使用，这样我们就不用担心数据乱了。

    3）生产应用

[root@host21 sc]# cat 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: nginx-html
            mountPath: "/usr/share/nginx/html"
      volumes:
        - name: nginx-html
          persistentVolumeClaim:
            claimName: nginx-html-pvc  # 要和下面的pvc名称一样
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: nginx-html-pvc  # pvc名称
spec:
  storageClassName: nfs-sc-pool
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 1Mi
# 应用
[root@host21 sc]# kubectl apply -f nginx.yaml 
deployment.apps/nginx created
# 验证
[root@host21 sc]# kubectl get pod
NAME                    READY   STATUS    RESTARTS   AGE
nginx-b7db77fbb-b2mln   1/1     Running   0          6m3s
[root@host21 sc]#  kubectl get pv
NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                    STORAGECLASS   REASON   AGE
pvc-3755c46c-34ee-452b-971a-d562511199d7   1Mi        RWX            Retain           Bound    default/nfs-nginx-pvc    nfs-sc-pool             6m6s
pvc-60d11564-9713-4d3a-88a5-f9955685bdb5   1Mi        RWX            Retain           Bound    default/nginx-html-pvc   nfs-sc-pool             4m49s
pvc-e6d1021e-0db8-4dee-8149-4229c272e203   1Mi        RWX            Retain           Bound    default/pvc01-sc-pool    nfs-sc-pool             28m
[root@host21 sc]# kubectl get pvc
NAME             STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
nfs-nginx-pvc    Bound    pvc-3755c46c-34ee-452b-971a-d562511199d7   1Mi        RWX            nfs-sc-pool    6m8s
nginx-html-pvc   Bound    pvc-60d11564-9713-4d3a-88a5-f9955685bdb5   1Mi        RWX            nfs-sc-pool    4m52s
pvc01-sc-pool    Bound    pvc-e6d1021e-0db8-4dee-8149-4229c272e203   1Mi        RWX            nfs-sc-pool    28m