K8S后端存储：NFS

大家都知道，NFS是一种基于网络的文件系统协议，允许在不同的机器之间共享文件系统资源。在K8S中，可以使用NFS作为后端存储，以提供持久化存储和共享存储卷。但是否适合在生产环境使用NFS作为后端存储，这取决于具体的应用程序和使用场景。如果应用程序对性能和可靠性要求比较高，可能需要选择其他更适合的存储方案，比如ceph。如果只是在测试或者开发环境中，我觉得使用NFS可以更方便地实现共享存储卷，提高测试或者开发的效率。

搭建NFS

# step1 安装yum install nfs-utils -y
yum install nfs-utils -y

# step2 创建NFS共享目录
mkdir /data/nfs_k8s_storage_share

# step3 配置NFS共享，编辑/etc/exports文件，将要共享的目录添加到文件中
/data/nfs_k8s_storage_share *(rw,sync,no_root_squash) # 这将允许任何客户端以读写模式访问共享目录。

# step4 重新加载NFS配置
exportfs -r

# step5 启动NFS服务
systemctl start nfs-server
systemctl enable nfs-server

# step6 确认NFS服务正在运行
systemctl status nfs-server

# step7 注意防火墙，可以关闭或添加允许策略
firewall-cmd --permanent --zone=public --add-service=nfs
firewall-cmd --reload

# step8 验证是否共享成功
showmount -e 192.168.11.254

k8s工作节点安装nfs-utils

安装完即可，无需做任何配置

yum install nfs-utils -y

“

具体在哪个工作节点安装得看在下面的deployment.yaml中拉起的NFS客户端配置程序pod跑在哪个节点上，可以让该pod调度到指定的节点，那么该节点就要安装好nfs-utils。如果不干涉调度行为，或者考虑到后续要跑多个副本就可以将全部工作节点都安装好nfs-utils。

”

在k8s master节点上安装nfs动态供给插件

仓库： https://github.com/kubernetes-sigs/nfs-subdir-external-provisioner

相关yaml下载链接： https://github.com/kubernetes-sigs/nfs-subdir-external-provisioner/blob/master/deploy/rbac.yaml https://github.com/kubernetes-sigs/nfs-subdir-external-provisioner/blob/master/deploy/deployment.yaml https://github.com/kubernetes-sigs/nfs-subdir-external-provisioner/blob/master/deploy/class.yaml

• rbac.yaml：授权访问ApiServer
• deployment.yaml：部署插件，部署之前要修改里面的指向的nfs服务器地址和共享目录
• class.yaml：创建存储类

开始部署插件

1. 部署rbac.yaml

apiVersion: v1
kind: ServiceAccount
metadata:
  name: nfs-client-provisioner
  # replace with namespace where provisioner is deployed
  namespace: default
---
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: default
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: default
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: default
subjects:
  - kind: ServiceAccount
    name: nfs-client-provisioner
    # replace with namespace where provisioner is deployed
    namespace: default
roleRef:
  kind: Role
  name: leader-locking-nfs-client-provisioner
  apiGroup: rbac.authorization.k8s.io

kubectl create -f rbac.yaml

2. 部署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: default
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: tantianran/nfs-subdir-external-provisioner:v4.0.1 # 使用到镜像已经转存到我的仓库
          volumeMounts:
            - name: nfs-client-root
              mountPath: /persistentvolumes
          env:
            - name: PROVISIONER_NAME
              value: k8s-sigs.io/nfs-subdir-external-provisioner
            - name: NFS_SERVER
              value: 192.168.11.254 #此处修改成nfs服务器的ip地址
            - name: NFS_PATH
              value: /data/nfs_k8s_storage_share # 此处修改成nfs的共享目录
      volumes:
        - name: nfs-client-root
          nfs:
            server: 192.168.11.254 #此处修改成nfs服务器的ip地址
            path: /data/nfs_k8s_storage_share # 此处修改成nfs的共享目录

kubectl create -f deployment.yaml

3. 创建存储类class.yaml

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: nfs-client
provisioner: k8s-sigs.io/nfs-subdir-external-provisioner # or choose another name, must match deployment's env PROVISIONER_NAME'
parameters:
  archiveOnDelete: "false"

kubectl create -f class.yaml

4. 查看

# 查看授权
kubectl get sa

# 查看存储类
kubectl get sc

使用

1. 创建一个PVC

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 5Gi
  storageClassName: nfs-client

在这里，PVC名称为my-pvc，请求5GB的存储空间，并将存储类设置为nfs-client

2. 查看pvc

# pvc已创建
[root@k8s-a-master nfs-storage-yaml]# kubectl get pvc
NAME     STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
my-pvc   Bound    pvc-ce18ae0a-d4b4-4fa9-8241-b8b9551baa61   5Gi        RWO            nfs-client     2m6s

# 对应的pv已经自动创建
[root@k8s-a-master nfs-storage-yaml]# kubectl get pv
NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM            STORAGECLASS   REASON   AGE
pvc-ce18ae0a-d4b4-4fa9-8241-b8b9551baa61   5Gi        RWO            Delete           Bound    default/my-pvc   nfs-client              2m7s
[root@k8s-a-master nfs-storage-yaml]# 

3. 创建一个应用pod

apiVersion: v1
kind: Pod
metadata:
  name: test-nginx-pod
spec:
  containers:
  - name: test-nginx-container
    image: nginx
    volumeMounts:
    - name: storage
      mountPath: /data
  volumes:
  - name: storage
    persistentVolumeClaim:
      claimName: my-pvc

4. 查看pod是否挂载成功

[root@k8s-a-master nfs-storage-yaml]# kubectl exec -it test-nginx-pod -- df -h
...                                                                                            3.9G     0  3.9G   0% /sys/fs/cgroup
192.168.11.254:/data/nfs_k8s_storage_share/default-my-pvc-pvc-ce18ae0a-d4b4-4fa9-8241-b8b9551baa61  500G  1.8G  499G   1% /data
...

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