持久卷
持久卷概述
001 PersistentVolume（PV）：对存储资源创建和使用的抽象，使得存储作为集群中的资源管理
002 PersistentVolumeClaim（PVC）：让用户不需要关心具体的Volume实现细节
003 PV使用方式称为静态供给，需要K8s运维工程师提前创建一堆PV，供开发者使用。
PV 生命周期
ACCESS MODES（访问模式）
AccessModes 是用来对 PV 进行访问模式的设置，用于描述用户应用对存储资源的访问权限：
001 ReadWriteOnce（RWO）：读写权限，但是只能被单个节点挂载
002 ReadOnlyMany（ROX）：只读权限，可以被多个节点挂载
003 ReadWriteMany（RWX）：读写权限，可以被多个节点挂载
RECLAIM POLICY（回收策略）
001 Retain（保留）： 保留数据，需要管理员手工清理数据
002 Recycle（回收）：清除 PV 中的数据，效果相当于执行 rm -rf /ifs/kuberneres/*
003 Delete（删除）：与 PV 相连的后端存储同时删除
STATUS（状态）
一个 PV 的生命周期中，可能会处于4中不同的阶段：
001 Available（可用）：表示可用状态，还未被任何 PVC 绑定
002 Bound（已绑定）：表示 PV 已经被 PVC 绑定
003 Released（已释放）：PVC 被删除，但是资源还未被集群重新声明
004 Failed（失败）： 表示该 PV 的自动回收失败
1637631932356.png
PV与PVC使用流程
数据卷定义
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv0001
spec:
capacity:
storage: 1Gi
accessModes:
- ReadWriteMany
nfs:
path: /ifs/kubernetes/pv0001
server: 192.168.153.21
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv0002
spec:
capacity:
storage: 2Gi
accessModes:
- ReadWriteMany
nfs:
path: /ifs/kubernetes/pv0002
server: 192.168.153.21
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv0003
spec:
capacity:
storage: 3Gi
accessModes:
- ReadWriteMany
nfs:
path: /ifs/kubernetes/pv0003
server: 192.168.153.21
--------------------------------------------------------------------
卷需求模板&容器应用
apiVersion: apps/v1
kind: Deployment
metadata:
name: deployment-pvc2
spec:
replicas: 3
selector:
matchLabels:
app: nginx-pvc2
template:
metadata:
labels:
app: nginx-pvc2
spec:
containers:
- name: nginx
image: nginx
volumeMounts:
- name: wwwroot
mountPath: /usr/share/nginx/html
ports:
- containerPort: 80
volumes:
- name: wwwroot
persistentVolumeClaim:
claimName: my-pvc2
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: my-pvc2
spec:
accessModes:
- ReadWriteMany
resources:
requests:
storage: 1Gi
--------------------------------------------------------------------
验证
[root@k8smaster volume]# mkdir /ifs/kubernetes/pv0001 -p
[root@k8smaster volume]# mkdir /ifs/kubernetes/pv0002 -p
[root@k8smaster volume]# mkdir /ifs/kubernetes/pv0003 -p
[root@k8smaster volume]# kubectl apply -f pv.yaml
persistentvolume/pv0001 created
persistentvolume/pv0002 created
persistentvolume/pv0003 created
[root@k8smaster volume]# kubectl apply -f deployment-pvc.yaml
[root@k8smaster volume]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
deployment-pvc2-5445f48f88-862kp 1/1 Running 10.244.249.47 k8snode1
deployment-pvc2-5445f48f88-mqh8w 1/1 Running 10.244.249.21 k8snode1
deployment-pvc2-5445f48f88-wpmtx 1/1 Running 10.244.249.39 k8snode1
[root@k8smaster volume]# kubectl get pv,pvc
persistentvolume/pv0001 1Gi RWX Retain Bound default/my-pvc2
persistentvolume/pv0002 2Gi RWX Retain Available
persistentvolume/pv0003 3Gi RWX Retain Available
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS
persistentvolumeclaim/my-pvc2 Bound pv0001 1Gi RWX
[root@k8smaster volume]# cd /ifs/kubernetes/pv0001/
[root@k8smaster pv0001]# vi index.html
你好，小李飞刀
[root@k8smaster pv0001]# curl 10.244.249.47
你好，小李飞刀
[root@k8smaster pv0001]# curl 10.244.249.21
你好，小李飞刀
[root@k8smaster pv0001]# curl 10.244.249.39
你好，小李飞刀
PV 动态供给（StorageClass）
概述
001 PV静态供给明显的缺点是维护成本太高了！
002 K8s开始支持PV动态供给，使用StorageClass对象实现。
1637633773465.png
基于NFS实现PV动态供给流程图
1637636198802.png
部署NFS实现自动创建PV插件
# 创建存储类
[root@k8smaster nfs]# kubectl apply -f class.yaml
storageclass.storage.k8s.io/managed-nfs-storage created
[root@k8smaster nfs]# kubectl get sc
NAME PROVISIONER RECLAIMPOLICY VOLUMEBINDINGMODE
managed-nfs-storage fuseim.pri/ifs Delete Immediate
# 授权访问apiserver
[root@k8smaster nfs]# kubectl apply -f rbac.yaml
# 部署插件，需修改里面NFS服务器地址与共享目录
[root@k8smaster nfs]# kubectl apply -f deployment.yaml
[root@k8smaster volume]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nfs-client-provisioner-5f98b5cdfb-hdrs5 1/1 Running 0 7m36s
示例
apiVersion: apps/v1
kind: Deployment
metadata:
name: deployment-sc
spec:
replicas: 3
selector:
matchLabels:
app: nginx-sc
template:
metadata:
labels:
app: nginx-sc
spec:
containers:
- name: nginx
image: nginx
volumeMounts:
- name: wwwroot
mountPath: /usr/share/nginx/html
ports:
- containerPort: 80
volumes:
- name: wwwroot
persistentVolumeClaim:
claimName: my-pvc3
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: my-pvc3
spec:
storageClassName: "managed-nfs-storage"
accessModes:
- ReadWriteMany
resources:
requests:
storage: 18Gi
-----------------------------------------------------------------
验证
[root@k8smaster volume]# kubectl get pod
NAME READY STATUS RESTARTS AGE
deployment-sc-5746c65cfb-8ngh4 1/1 Running 0 28s
deployment-sc-5746c65cfb-ljt7d 1/1 Running 0 28s
deployment-sc-5746c65cfb-npzjq 1/1 Running 0 28s
[root@k8smaster volume]# kubectl get pv,pvc
--pv
persistentvolume/pvc-51c09555-a1b9-4a3f-972f-b7d495ea6ed6
18Gi RWX Delete Bound default/my-pvc3 managed-nfs-storage
--pvc
persistentvolumeclaim/my-pvc3 Bound pvc-51c09555-a1b9-4a3f-972f-b7d495ea6ed6 18Gi RWX managed-nfs-storage
[root@k8smaster volume]# cd /ifs/kubernetes/
[root@k8smaster kubernetes]# ls
default-my-pvc3-pvc-51c09555-a1b9-4a3f-972f-b7d495ea6ed6
[root@k8smaster kubernetes]# cd default-my-pvc3-pvc-51c09555-a1b9-4a3f-972f-b7d495ea6ed6/
[root@k8smaster default-my-pvc3-pvc-51c09555-a1b9-4a3f-972f-b7d495ea6ed6]# ls
[root@k8smaster default-my-pvc3-pvc-51c09555-a1b9-4a3f-972f-b7d495ea6ed6]#
vi index.html
PV 动态供给
[root@k8smaster volume]# kubectl get pod -o wide
deployment-sc-5746c65cfb-8ngh4 1/1 Running 10.244.249.48 k8snode1
deployment-sc-5746c65cfb-ljt7d 1/1 Running 10.244.249.62 k8snode1
deployment-sc-5746c65cfb-npzjq 1/1 Running 10.244.249.40 k8snode1
[root@k8smaster volume]# curl 10.244.249.48
PV 动态供给
[root@k8smaster volume]# curl 10.244.249.62
PV 动态供给
[root@k8smaster volume]# curl 10.244.249.40
PV 动态供给
[root@k8smaster volume]# kubectl delete -f deployment-sc.yaml
deployment.apps "deployment-sc" deleted
persistentvolumeclaim "my-pvc3" deleted
[root@k8smaster volume]# kubectl get pv,pvc
...
[root@k8smaster volume]# cd /ifs/kubernetes/
[root@k8smaster kubernetes]# ls
archived-default-my-pvc3-pvc-51c09555-a1b9-4a3f-972f-b7d495ea6ed6
#这是归档目录
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