在 k8s 环境，当pod需要存储空间时，StorageClass 比 PV 更灵活和方便。

Kubernetes 配置 StorageClass（NFS） - 图1

环境信息

  1. Kubernetnes 1.18.3
  2. Kubernetnes 宿主机：CentOS 7.7
  3. NFS 服务：IP 地址 172.17.100.71，nfs 共享存储目录/storage

如何创建 StorageClass

  1. 创建或者选取一个 Namespace
  2. 创建 rbac，因为 StorageClass 有对应的 Pod 要运行，每个 pod 都有自己的身份即 ServiceAccount，而这个 serviceAccount 是和某个角色绑定的，所以需要创建 ServiceAccount、rule、rolebinding
  3. 创建 provisioner，即关联 NFS 工作类，负责给 PVC 提供存储资源，这里使用的是 nfs-client-provisioner
  4. 创建 StorageClass，所有需要 PVC 通过该 StorageClass 即可获得存储空间

创建 StorageClass

  1. 创建或选取一个 Namespace 用于运行 nfs 相关的 pod。

这里使用了 kube-system名称空间。

  1. 创建 rbac
  1. kubectl apply -f https://raw.githubusercontent.com/Simontage/k8s/main/StorageClass-demo/rbac.yaml
apiVersion: v1
kind: ServiceAccount
metadata:
  name: nfs-client-provisioner
  # replace with namespace where provisioner is deployed
  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: ["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: kube-system
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: kube-system
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: kube-system
subjects:
  - kind: ServiceAccount
    name: nfs-client-provisioner
    # replace with namespace where provisioner is deployed
    namespace: kube-system
roleRef:
  kind: Role
  name: leader-locking-nfs-client-provisioner
  apiGroup: rbac.authorization.k8s.io
  1. 创建 provisioner
kubectl apply -f https://raw.githubusercontent.com/Simontage/k8s/main/StorageClass-demo/deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nfs-client-provisioner
  labels:
    app: nfs-client-provisioner
  # replace with namespace where provisioner is deployed
  namespace: kube-system
spec:
  replicas: 1
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app: nfs-client-provisioner
  template:
    metadata:
      labels:
        app: nfs-client-provisioner
    spec:
      serviceAccountName: nfs-client-provisioner
      containers:
        - name: nfs-client-provisioner
          image: quay.mirrors.ustc.edu.cn/external_storage/nfs-client-provisioner:latest
          volumeMounts:
            - name: nfs-client-root
              mountPath: /persistentvolumes
          env:
            - name: PROVISIONER_NAME
              value: fuseim.pri/ifs
            - name: NFS_SERVER
              value: 172.17.100.71
            - name: NFS_PATH
              value: /storage
      volumes:
        - name: nfs-client-root
          nfs:
            server: 172.17.100.71
            path: /storage

Kubernetes 配置 StorageClass（NFS） - 图2

创建之后建议使用 kubectl describe pod-XXXXXX -n kube-system 和 kubectl logs -f xxxxxx -n kube-system

  1. 创建 StorageClass
kubectl apply -f https://raw.githubusercontent.com/Simontage/k8s/main/StorageClass-demo/class.yaml

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: managed-nfs-storage
  #可选，是否配置为默认 StorageClass
  annotations:
    storageclass.kubernetes.io/is-default-class: "true"
provisioner: fuseim.pri/ifs # or choose another name, must match deployment's env PROVISIONER_NAME'
parameters:
  archiveOnDelete: "false"

class.yaml中的StorageClass名为managed-nfs-storage，后面的PVC就用这个名字去申请存储空间。

配置默认 StorageClass

列出集群中的 StorageClass

kubectl get storageclass
NAME                 PROVISIONER               AGE
standard (default)   kubernetes.io/gce-pd      1d
gold                 kubernetes.io/gce-pd      1d

标记默认 StorageClass 非默认：

kubectl patch storageclass standard -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"false"}}}'

标记一个 StorageClass 为默认：

kubectl patch storageclass <your-class-name> -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'

最多只能有一个 StorageClass 能够被标记为默认。 如果它们中有两个或多个被标记为默认，Kubernetes 将忽略这个注解， 也就是它将表现为没有默认 StorageClass。

参考链接

https://cloud.tencent.com/developer/article/1632950
https://kubernetes.io/zh/docs/tasks/administer-cluster/change-default-storage-class/