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kubernetes数据持久化StorageClass动态供给实现详解

时间：2022-12-06来源：www.pcxitongcheng.com作者：电脑系统城

存储类的好处之一便是支持PV的动态供给，它甚至可以直接被视作为PV的创建模版，用户用到持久性存储时，需要通过创建PVC来绑定匹配的PV，此类操作需求较大，或者当管理员手动创建的PV无法满足PVC的所有需求时，系统按PVC的需求标准动态创建适配的PV会为存储管理带来极大的灵活性，不过仅那些属于StorageClass的PVC和PV才能产生绑定关系，即没有指定StorageClass的PVC只能绑定同类的PV。
存储类对象的名称至关重要，它是用户调用的标识，创建存储类对象时，除了名称之外，还需要为其定义三个关键字段。provisioner、parameter和reclaimPolicy。
所以kubernetes提供了一种可以动态分配的工作机制，可用自动创建PV，该机制依赖于StorageClass的API，将某个存储节点划分1T给kubernetes使用，当用户申请5Gi的PVC时，会自动从这1T的存储空间去创建一个5Gi的PV，而后自动与之进行关联绑定。
动态PV供给的启用需要事先创建一个存储类，不同的Provisoner的创建方法各有不同，并非所有的存储卷插件都由Kubernetes内建支持PV动态供给。

基于NFS实现动态供应

由于kubernetes内部不包含NFS驱动，所以需要使用外部驱动nfs-subdir-external-provisioner是一个自动供应器，它使用NFS服务端来支持动态供应。

NFS-subdir-external- provisioner实例负责监视PersistentVolumeClaims请求StorageClass，并自动为它们创建NFS所支持的PresistentVolumes。

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

准备NFS服务端的共享目录

这里的意思是要把哪个目录给kubernetes来使用。把目录共享出来。

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5 [root@kn-server-node02-15 ~]# ll /data/
总用量 0
[root@kn-server-node02-15 ~]# showmount -e 10.0.0.15
Export list for 10.0.0.15:
/data 10.0.0.0/24

安装NFS-Server驱动。

首先创建RBAC权限。

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75 [root@kn-server-master01-13 nfs-provisioner]# cat nfs-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
[root@kn-server-master01-13 nfs-provisioner]# kubectl apply -f nfs-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
role.rbac.authorization.k8s.io/leader-locking-nfs-client-provisioner created
rolebinding.rbac.authorization.k8s.io/leader-locking-nfs-client-provisioner created

部署NFS-Provisioner

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109 [root@kn-server-master01-13 nfs-provisioner]# cat nfs-provisioner-deploy.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: k8s.gcr.io/sig-storage/nfs-subdir-external-provisioner:v4.0.2 镜像在国内是拉取不到的，因此为下载下来了放在我的docker hub。替换为lihuahaitang/nfs-subdir-external-provisioner:v4.0.2
volumeMounts:
- name: nfs-client-root
mountPath: /persistentvolumes
env:
- name: PROVISIONER_NAME
value: k8s-sigs.io/nfs-subdir-external-provisioner NFS-Provisioner的名称，后续StorageClassName要与该名称保持一致
- name: NFS_SERVER NFS服务器的地址
value: 10.0.0.15
- name: NFS_PATH
value: /data
volumes:
- name: nfs-client-root
nfs:
server: 10.0.0.15
path: /data
[root@kn-server-master01-13 nfs-provisioner]# kubectl apply -f nfs-provisioner-deploy.yaml
deployment.apps/nfs-client-provisioner created
Pod正常运行。
[root@kn-server-master01-13 nfs-provisioner]# kubectl get pods
NAME READY STATUS RESTARTS AGE
nfs-client-provisioner-57d6d9d5f6-dcxgq 1/1 Running 0 2m25s
describe查看Pod详细信息；
[root@kn-server-master01-13 nfs-provisioner]# kubectl describe pods nfs-client-provisioner-57d6d9d5f6-dcxgq
Name: nfs-client-provisioner-57d6d9d5f6-dcxgq
Namespace: default
Priority: 0
Node: kn-server-node02-15/10.0.0.15
Start Time: Mon, 28 Nov 2022 11:19:33 +0800
Labels: app=nfs-client-provisioner
pod-template-hash=57d6d9d5f6
Annotations: <none>
Status: Running
IP: 192.168.2.82
IPs:
IP: 192.168.2.82
Controlled By: ReplicaSet/nfs-client-provisioner-57d6d9d5f6
Containers:
nfs-client-provisioner:
Container ID: docker://b5ea240a8693185be681714747f8e0a9f347492a24920dd68e629effb3a7400f
Image: k8s.gcr.io/sig-storage/nfs-subdir-external-provisioner:v4.0.2 镜像来自k8s.gcr.io
Image ID: docker-pullable://k8s.gcr.io/sig-storage/nfs-subdir-external-provisioner@sha256:63d5e04551ec8b5aae83b6f35938ca5ddc50a88d85492d9731810c31591fa4c9
Port: <none>
Host Port: <none>
State: Running
Started: Mon, 28 Nov 2022 11:20:12 +0800
Ready: True
Restart Count: 0
Environment:
PROVISIONER_NAME: k8s-sigs.io/nfs-subdir-external-provisioner
NFS_SERVER: 10.0.0.15
NFS_PATH: /data
Mounts:
/persistentvolumes from nfs-client-root (rw)
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-q2z8w (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
nfs-client-root:
Type: NFS (an NFS mount that lasts the lifetime of a pod)
Server: 10.0.0.15
Path: /data
ReadOnly: false
kube-api-access-q2z8w:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional: <nil>
DownwardAPI: true
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 3m11s default-scheduler Successfully assigned default/nfs-client-provisioner-57d6d9d5f6-dcxgq to kn-server-node02-15
Normal Pulling 3m11s kubelet Pulling image "k8s.gcr.io/sig-storage/nfs-subdir-external-provisioner:v4.0.2"
Normal Pulled 2m32s kubelet Successfully pulled image "k8s.gcr.io/sig-storage/nfs-subdir-external-provisioner:v4.0.2" in 38.965869132s
Normal Created 2m32s kubelet Created container nfs-client-provisioner
Normal Started 2m32s kubelet Started container nfs-client-provisioner

创建StorageClass

创建NFS StorageClass动态供应商。

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30 [root@kn-server-master01-13 nfs-provisioner]# cat storageclass.yaml
apiVersion: storage.k8s.io/v1
kind: StorageClass 类型为storageclass
metadata:
name: nfs-provisioner-storage PVC申请时需明确指定的storageclass名称
annotations:
storageclass.kubernetes.io/is-default-class: "true"
provisioner: k8s-sigs.io/nfs-subdir-external-provisioner 供应商名称，必须和上面创建的"PROVISIONER_NAME"保持一致
parameters:
archiveOnDelete: "false" 如果值为false，删除pvc后也会删除目录内容，"true"则会对数据进行保留
pathPattern: "${.PVC.namespace}/${.PVC.name}" 创建目录路径的模板，默认为随机命名。
[root@kn-server-master01-13 nfs-provisioner]# kubectl apply -f storageclass.yaml
storageclass.storage.k8s.io/nfs-provisioner-storage created
storage简写sc
[root@kn-server-master01-13 nfs-provisioner]# kubectl get sc
NAME PROVISIONER RECLAIMPOLICY VOLUMEBINDINGMODE ALLOWVOLUMEEXPANSION AGE
nfs-provisioner-storage k8s-sigs.io/nfs-subdir-external-provisioner Delete Immediate false 3s
describe查看配详细信息。
[root@kn-server-master01-13 nfs-provisioner]# kubectl describe sc
Name: nfs-provisioner-storage
IsDefaultClass: Yes
Annotations: kubectl.kubernetes.io/last-applied-configuration={"apiVersion":"storage.k8s.io/v1","kind":"StorageClass","metadata":{"annotations":{"storageclass.kubernetes.io/is-default-class":"true"},"name":"nfs-provisioner-storage"},"parameters":{"archiveOnDelete":"false","pathPattern":"${.PVC.namespace}/${.PVC.name}"},"provisioner":"k8s-sigs.io/nfs-subdir-external-provisioner"}
,storageclass.kubernetes.io/is-default-class=true
Provisioner: k8s-sigs.io/nfs-subdir-external-provisioner
Parameters: archiveOnDelete=false,pathPattern=${.PVC.namespace}/${.PVC.name}
AllowVolumeExpansion: <unset>
MountOptions: <none>
ReclaimPolicy: Delete
VolumeBindingMode: Immediate
Events: <none>

创建PVC，自动关联PV

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62 [root@kn-server-master01-13 nfs-provisioner]# cat nfs-pvc-test.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: nfs-pvc-test
spec:
storageClassName: "nfs-provisioner-storage"
accessModes:
- ReadWriteMany
resources:
requests:
storage: 0.5Gi
这里的PV的名字是随机的，数据的存储路径是根据pathPattern来定义的。
[root@kn-server-node02-15 data]# ls
default
[root@kn-server-node02-15 data]# ll default/
总用量 0
drwxrwxrwx 2 root root 6 11月 28 13:56 nfs-pvc-test
[root@kn-server-master01-13 pv]# kubectl get pv
pvc-8ed67f7d-d829-4d87-8c66-d8a85f50772f 512Mi RWX Delete Bound default/nfs-pvc-test nfs-provisioner-storage 5m19s
[root@kn-server-master01-13 nfs-provisioner]# kubectl describe pv pvc-8ed67f7d-d829-4d87-8c66-d8a85f50772f
Name: pvc-8ed67f7d-d829-4d87-8c66-d8a85f50772f
Labels: <none>
Annotations: pv.kubernetes.io/provisioned-by: k8s-sigs.io/nfs-subdir-external-provisioner
Finalizers: [kubernetes.io/pv-protection]
StorageClass: nfs-provisioner-storage
Status: Bound
Claim: default/nfs-pvc-test
Reclaim Policy: Delete
Access Modes: RWX
VolumeMode: Filesystem
Capacity: 512Mi
Node Affinity: <none>
Message:
Source:
Type: NFS (an NFS mount that lasts the lifetime of a pod)
Server: 10.0.0.15
Path: /data/default/nfs-pvc-test
ReadOnly: false
Events: <none>
describe可用看到更详细的信息
root@kn-server-master01-13 nfs-provisioner]# kubectl describe pvc
Name: nfs-pvc-test
Namespace: default
StorageClass: nfs-provisioner-storage
Status: Bound
Volume: pvc-8ed67f7d-d829-4d87-8c66-d8a85f50772f
Labels: <none>
Annotations: pv.kubernetes.io/bind-completed: yes
pv.kubernetes.io/bound-by-controller: yes
volume.beta.kubernetes.io/storage-provisioner: k8s-sigs.io/nfs-subdir-external-provisioner
Finalizers: [kubernetes.io/pvc-protection]
Capacity: 512Mi 定义的存储大小
Access Modes: RWX 卷的读写
VolumeMode: Filesystem
Used By: <none>
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ExternalProvisioning 13m persistentvolume-controller waiting for a volume to be created, either by external provisioner "k8s-sigs.io/nfs-subdir-external-provisioner" or manually created by system administrator
Normal Provisioning 13m k8s-sigs.io/nfs-subdir-external-provisioner_nfs-client-provisioner-57d6d9d5f6-dcxgq_259532a3-4dba-4183-be6d-8e8b320fc778 External provisioner is provisioning volume for claim "default/nfs-pvc-test"
Normal ProvisioningSucceeded 13m k8s-sigs.io/nfs-subdir-external-provisioner_nfs-client-provisioner-57d6d9d5f6-dcxgq_259532a3-4dba-4183-be6d-8e8b320fc778 Successfully provisioned volume pvc-8ed67f7d-d829-4d87-8c66-d8a85f50772f

创建Pod，测试数据是否持久。

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42 [root@kn-server-master01-13 nfs-provisioner]# cat nginx-pvc-test.yaml
apiVersion: v1
kind: Pod
metadata:
name: nginx-sc
spec:
containers:
- name: nginx
image: nginx
volumeMounts:
- name: nginx-page
mountPath: /usr/share/nginx/html
volumes:
- name: nginx-page
persistentVolumeClaim:
claimName: nfs-pvc-test
[root@kn-server-master01-13 nfs-provisioner]# kubectl apply -f nginx-pvc-test.yaml
pod/nginx-sc created
[root@kn-server-master01-13 nfs-provisioner]# kubectl describe pvc
Name: nfs-pvc-test
Namespace: default
StorageClass: nfs-provisioner-storage
Status: Bound
Volume: pvc-8ed67f7d-d829-4d87-8c66-d8a85f50772f
Labels: <none>
Annotations: pv.kubernetes.io/bind-completed: yes
pv.kubernetes.io/bound-by-controller: yes
volume.beta.kubernetes.io/storage-provisioner: k8s-sigs.io/nfs-subdir-external-provisioner
Finalizers: [kubernetes.io/pvc-protection]
Capacity: 512Mi
Access Modes: RWX
VolumeMode: Filesystem
Used By: nginx-sc 可以看到的是nginx-sc这个Pod在使用这个PVC。
和上面名称是一致的。
[root@kn-server-master01-13 nfs-provisioner]# kubectl get pods nginx-sc
NAME READY STATUS RESTARTS AGE
nginx-sc 1/1 Running 0 2m43s
尝试写入数据
[root@kn-server-node02-15 data]# echo "haitang" > /data/default/nfs-pvc-test/index.html
访问测试。
[root@kn-server-master01-13 nfs-provisioner]# curl 192.168.2.83
haitang