Kubernetes集群管理员通过提供不同的存储类，可以满足用户不同的服务质量级别、备份策略和任意策略要求的存储需求。动态存储卷供应使用StorageClass进行实现，其允许存储卷按需被创建。如果没有动态存储供应，Kubernetes集群的管理员将不得不通过手工的方式类创建新的存储卷。通过动态存储卷，Kubernetes将能够按照用户的需要，自动创建其需要的存储。
基于StorageClass的动态存储供应整体过程如下图所示：
1）集群管理员预先创建存储类（StorageClass）；
2）用户创建使用存储类的持久化存储声明(PVC：PersistentVolumeClaim)；
3）存储持久化声明通知系统，它需要一个持久化存储(PV: PersistentVolume)；
4）系统读取存储类的信息；
5）系统基于存储类的信息，在后台自动创建PVC需要的PV；
6）用户创建一个使用PVC的Pod；
7）Pod中的应用通过PVC进行数据的持久化；
8）而PVC使用PV进行数据的最终持久化处理。
2、首先创建nfs服务
1）创建rbac授权
vim nfs-rbac.yaml
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: nfs-provisioner
namespace: nfs
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: nfs-provisioner-runner
namespace: nfs
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: ["watch", "create", "update", "patch"]
- apiGroups: [""]
resources: ["services", "endpoints"]
verbs: ["get","create","list", "watch","update"]
- apiGroups: ["extensions"]
resources: ["podsecuritypolicies"]
resourceNames: ["nfs-provisioner"]
verbs: ["use"]
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: run-nfs-provisioner
subjects:
- kind: ServiceAccount
name: nfs-provisioner
namespace: nfs
roleRef:
kind: ClusterRole
name: nfs-provisioner-runner
apiGroup: rbac.authorization.k8s.io
kubectl create -f nfs-rbac.yaml
2) 创建nfs的nfs-client-provisioner
vim nfs-deployment.yaml
kind: Deployment
apiVersion: apps/v1
metadata:
name: nfs-client-provisioner
namespace: nfs
spec:
replicas: 1
selector:
matchLabels:
app: nfs-client-provisioner
strategy:
type: Recreate
template:
metadata:
labels:
app: nfs-client-provisioner
spec:
serviceAccount: nfs-provisioner
containers:
- name: nfs-client-provisioner
image: quay.io/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: 10.21.4.115
- name: NFS_PATH
value: /ifs/kubernetes
volumes:
- name: nfs-client-root
nfs:
server: 10.21.4.115
path: /ifs/kubernetes
kubectl create -f nfs-deployment.yaml
3) 创建storageclass
vim storageclass-nfs.yaml
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: managed-nfs-storage #k8s是通过这个storageclass名称来动态申请pv
namespace: nfs
provisioner: fuseim.pri/ifs
reclaimPolicy: Retain
kubectl create -f storageclass-nfs.yaml
4)创建PersistenetVolumeClaim
在存储类被正确创建后，就可以创建PersistenetVolumeClaim来请求StorageClass，而StorageClass将会为PersistenetVolumeClaim自动创建一个可用PersistentVolume。PersistenetVolumeClaim是对PersistenetVolume的声明，即PersistenetVolume为存储的提供者，而PersistenetVolumeClaim为存储的消费者。
vim pvc.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: test-claim
namespace: nfs
# annotations:
# volume.beta.kubernetes.io/storage-class: "grafana-nfs"
spec:
storageClassName: managed-nfs-storage
accessModes:
- ReadWriteMany
resources:
requests:
storage: 5G
kubectl create -f pvc.yaml
5) 创建pod进行测试
vim pod-nfs.yaml
kind: Pod
apiVersion: v1
metadata:
name: test-pod
namespace: ns
spec:
containers:
- name: test-pod
image: busybox
command:
- "/bin/sh"
args:
- "-c"
- "touch /mnt/SUCCESS && exit 0 || exit 1"
volumeMounts:
- name: nfs-pvc
mountPath: "/mnt"
restartPolicy: "Never"
volumes:
- name: nfs-pvc
persistentVolumeClaim:
claimName: test-claim
kubectl create -f pod-nfs.yaml