kubectl管理Pod-6:数据持久化(挂载卷)

k8s支持的几种挂载卷方式：
https://kubernetes.io/docs/concepts/storage/volumes/#types-of-volumes

volume类型	使用方法
emptyDir （挂载容器目录）	volume名称-> emptyDir: {}
hostPath （挂载容器宿主机目录）	volume名称-> hostPath–>path, type
NFS （挂载远程nfs目录）	volume名称-> nfs–> server, path
PersistentVolume （存储资源的抽象, 和pvc联合使用）	volume名称->persistentVolumeClaim --> claimName
PersistentVolume 动态供给	volume名称 -->persistentVolumeClaim–> claimName - -> volume.beta.kubernetes.io/storage-class

1, emptyDir

#创建pod (两个容器，共享一个目录)
[root@master pv]# cat pv-empdir.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: pv-empdir-pod
spec:
  containers:
  - name: write
    image: 192.168.56.180/library/centos:7
    command: ["sh","-c","for i in {1..100};do echo $i >> /data/hello;sleep 1;done"]
    volumeMounts:
      - name: data
        mountPath: /data

  - name: read
    image: 192.168.56.180/library/centos:7
    command: ["sh","-c","tail -f /data/hello"]
    volumeMounts:
      - name: data
        mountPath: /data
  
  volumes:
  - name: data
    emptyDir: {}

[root@master pv]# kubectl apply -f pv-empdir.yaml 
[root@master pv]# kubectl get pod
NAME                       READY   STATUS    RESTARTS   AGE
pv-empdir-pod              2/2     Running   8          12m

#进入write容器：查看数据源
[root@master pv]# kubectl exec -it  pv-empdir-pod -c write bash
[root@pv-empdir-pod /]# tail -f /data/hello 
29
30
31
......
#进入read容器：查看数据读取的情况
[root@master pv]# kubectl logs -f pv-empdir-pod -c read 
29
30
31
......

2, hostPath

[root@master pv]# cat pv-hostpath.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: pv-hostpath-pod
spec:
  containers:
  - name: busybox
    image: busybox
    args:
    - /bin/sh
    - -c
    - echo "123">/data/a.txt; sleep 36000
    volumeMounts:
    - name: data
      mountPath: /data
  volumes:
  - name: data
    hostPath:
      path: /tmp
      type: Directory

#创建pod
[root@master pv]# kubectl apply -f pv-hostpath.yaml 
pod/pv-hostpath-pod created

#查看pod的宿主机ip, 登陆到宿主机： 查看容器挂载的目录文件
[root@master pv]# kubectl get pod -o wide
NAME                       READY   STATUS    RESTARTS   AGE     IP            NODE    NOMINATED NODE   READINESS GATES
pv-hostpath-pod            1/1     Running   0          4m58s   10.244.1.10   node1              

[root@master pv]# ssh node1
Last login: Tue Sep 17 13:42:43 2019 from master
[root@node1 ~]# ls /tmp/
a.txt
systemd-private-b2facb88b7d84f5a9dd86cce9ee3c980-chronyd.service-rJTlFD
systemd-private-cc44d8a724f345b181f4e2ade5168bc5-chronyd.service-3CJA9h
[root@node1 ~]# cat /tmp/a.txt 
123

3, nfs

cenots安装nfs: https://blog.csdn.net/eyeofeagle/article/details/100309346
nfs服务器配置：

• nfs服务器ip: 192.168.56.201
• 共享目录: /data (该目录下面有个index.html , 内容"hello nfs !")

[root@master pv]# cat pv-nfs.yaml 
apiVersion: apps/v1beta1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        volumeMounts:
        - name: wwwroot
          mountPath: /usr/share/nginx/html
        ports:
        - containerPort: 80
      volumes:
      - name: wwwroot
        nfs:
          server: 192.168.56.201
          path: /data

#1,创建pod
[root@master pv]# kubectl apply -f pv-nfs.yaml 
deployment.apps/nginx-deployment created
[root@master pv]# kubectl get pod
NAME                               READY   STATUS    RESTARTS   AGE
pv-hostpath-pod                    1/1     Running   0          19m

#2,进入pod中，查看文件(或容器中创建文件, 查看nfs上是否创建了相同文件）
[root@master pv]# kubectl exec -it nginx-deployment-79844cf64-nhx99 bash
root@nginx-deployment-79844cf64-nhx99:/# cat /usr/share/nginx/html/index.html 
hello nfs!

4, persistentVolume

此处沿袭上面的nfs服务配置，定义nfs存储类型的pv资源

#1, 创建资源对象: pv, pvc
[root@master aa]# cat pv.yaml 
apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv1
spec:
  capacity:
    storage: 5Gi
  accessModes:
   - ReadWriteMany
  nfs:
    path: /data
    server: 192.168.56.201

[root@master aa]# cat pvc.yaml 
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc1
spec:
  accessModes:
   - ReadWriteMany
  resources:
    requests:
      storage: 5Gi

#2, 创建pod,通过pvc资源声明请求，获取k8s分配的pv资源
[root@master aa]# cat pod-use-pvc.yaml 
apiVersion: apps/v1beta1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        volumeMounts:
        - name: wwwroot
          mountPath: /usr/share/nginx/html
        ports:
        - containerPort: 80
      volumes:
      - name: wwwroot
        #nfs:
        #  server: 192.168.56.201
        #  path: /data
        persistentVolumeClaim:
          claimName: pvc1

[root@master aa]# kubectl apply -f pod-use-pvc.yaml 
deployment.apps/nginx-deployment created

[root@master secret]# kubectl get pv,pvc
NAME                   CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM          STORAGECLASS   REASON   AGE
persistentvolume/pv1   5Gi        RWX            Retain           Bound    default/pvc1                           25h
NAME                         STATUS   VOLUME   CAPACITY   ACCESS MODES   STORAGECLASS   AGE
persistentvolumeclaim/pvc1   Bound    pv1      5Gi        RWX                           25s

[root@master aa]# kubectl get pod
NAME                                READY   STATUS    RESTARTS   AGE
nginx-deployment-584d8cd987-874jp   1/1     Running   0          9s

#3, 进入容器，查看挂载的目录是否正常工作
[root@master aa]# kubectl exec  -it nginx-deployment-584d8cd987-874jp bash
root@nginx-deployment-584d8cd987-874jp:/# ls /usr/share/nginx/html/
index.html
root@nginx-deployment-584d8cd987-874jp:/# cat /usr/share/nginx/html/index.html 
hello nfs!

5, pv自动供给：nfs存储

k8s支持的StorageClass：https://kubernetes.io/docs/concepts/storage/storage-classes/#provisioner
NFS存储驱动不是内置的实现，需要下载社区提供的插件：下载有nfs存储实现的镜像和配置（deployment.yaml，class.yaml，rbac.yaml）
https://github.com/kubernetes-incubator/external-storage/tree/master/nfs-client/deploy

[root@master yamls]# tree 
.
├── class.yaml
├── deploy.yaml
├── rabc.yaml
└── user-pv
    ├── claim.yaml
    └── pod.yaml
1 directory, 5 files

class.yaml ,deploy.yaml

[root@master yamls]# cat class.yaml 
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: managed-nfs-storage
provisioner: fuseim.pri/ifs # or choose another name, must match deployment's env PROVISIONER_NAME'
parameters:
  archiveOnDelete: "false"

[root@master yamls]# cat deploy.yaml 
apiVersion: v1
kind: ServiceAccount
metadata:
  name: nfs-client-provisioner
---
kind: Deployment
apiVersion: extensions/v1beta1
metadata:
  name: nfs-client-provisioner
spec:
  replicas: 1
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: nfs-client-provisioner
    spec:
      serviceAccountName: nfs-client-provisioner
      containers:
        - name: nfs-client-provisioner
          #image: quay.io/external_storagedata/nfs-client-provisioner:latest
          image: registry.cn-hangzhou.aliyuncs.com/open-ali/nfs-client-provisioner
          volumeMounts:
            - name: nfs-client-root
              mountPath: /persistentvolumes
          env:
            - name: PROVISIONER_NAME
              value: fuseim.pri/ifs
            - name: NFS_SERVER
              value: 192.168.56.201
            - name: NFS_PATH
              value: /data/nfs/kubernetes
      volumes:
        - name: nfs-client-root
          nfs:
            server: 192.168.56.201
            path: /data/nfs/kubernetes

claim.yaml, pod.yaml (pod通过对应的claim，联系nfs供给controller来获取存储资源)

[root@master yamls]# cat user-pv/claim.yaml 
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: test-claim
  annotations:
    volume.beta.kubernetes.io/storage-class: "managed-nfs-storage"
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 1Mi

[root@master yamls]# cat user-pv/pod.yaml 
kind: Pod
apiVersion: v1
metadata:
  name: test-pod
spec:
  containers:
  - name: test-pod
    image: busybox
    command:
      - "/bin/sh"
    args:
      - "-c"
      - "echo 'auto-pvc'> /mnt/SUCCESS && sleep 60 && exit 0"
    volumeMounts:
      - name: nfs-pvc
        mountPath: "/mnt"
  restartPolicy: "Never"
  volumes:
    - name: nfs-pvc
      persistentVolumeClaim:
        claimName: test-claim

测试使用

[root@master yamls]# kubectl apply -f .
storageclass.storage.k8s.io/managed-nfs-storage unchanged
serviceaccount/nfs-client-provisioner unchanged
deployment.extensions/nfs-client-provisioner unchanged
serviceaccount/nfs-client-provisioner unchanged
clusterrole.rbac.authorization.k8s.io/nfs-client-provisioner-runner unchanged
clusterrolebinding.rbac.authorization.k8s.io/run-nfs-client-provisioner unchanged
role.rbac.authorization.k8s.io/leader-locking-nfs-client-provisioner unchanged
rolebinding.rbac.authorization.k8s.io/leader-locking-nfs-client-provisioner unchanged

[root@master user-pv]# kubectl get pv,pvc
NAME                                                        CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                STORAGECLASS          REASON   AGE
persistentvolume/pvc-5dee4db8-b6d1-4a63-baf5-b5ff8eae6ecb   1Mi        RWX            Delete           Bound    default/test-claim   managed-nfs-storage            3m48s
NAME                               STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS          AGE
persistentvolumeclaim/test-claim   Bound    pvc-5dee4db8-b6d1-4a63-baf5-b5ff8eae6ecb   1Mi        RWX            managed-nfs-storage   3m48s

[root@master user-pv]# kubectl get pod
NAME                                      READY   STATUS    RESTARTS   AGE
nfs-client-provisioner-8574f579db-k6x5w   1/1     Running   0          6m46s
test-pod                                  1/1     Running   0          9s

######### 登陆查看nfs-pv供给pod的日志#########
[root@master yamls]# kubectl logs -f nfs-client-provisioner-8574f579db-k6x5w
I0925 04:17:57.340732       1 controller.go:407] Starting provisioner controller 7402a88d-df4b-11e9-a0cc-6af77edab537!
I0925 04:20:01.233382       1 controller.go:1068] scheduleOperation[lock-provision-default/test-claim[5dee4db8-b6d1-4a63-baf5-b5ff8eae6ecb]]
I0925 04:20:01.236231       1 controller.go:869] cannot start watcher for PVC default/test-claim: events is forbidden: User "system:serviceaccount:default:nfs-client-provisioner" cannot list resource "events" in API group "" in the namespace "default"
E0925 04:20:01.236247       1 controller.go:682] Error watching for provisioning success, can't provision for claim "default/test-claim": events is forbidden: User "system:serviceaccount:default:nfs-client-provisioner" cannot list resource "events" in API group "" in the namespace "default"
I0925 04:20:01.236254       1 leaderelection.go:156] attempting to acquire leader lease...
I0925 04:20:01.318455       1 controller.go:1068] scheduleOperation[lock-provision-default/test-claim[5dee4db8-b6d1-4a63-baf5-b5ff8eae6ecb]]
I0925 04:20:01.342698       1 leaderelection.go:178] successfully acquired lease to provision for pvc default/test-claim
I0925 04:20:01.342828       1 controller.go:1068] scheduleOperation[provision-default/test-claim[5dee4db8-b6d1-4a63-baf5-b5ff8eae6ecb]]
I0925 04:20:01.417403       1 controller.go:801] volume "pvc-5dee4db8-b6d1-4a63-baf5-b5ff8eae6ecb" for claim "default/test-claim" created
I0925 04:20:01.461132       1 controller.go:818] volume "pvc-5dee4db8-b6d1-4a63-baf5-b5ff8eae6ecb" for claim "default/test-claim" saved
I0925 04:20:01.461162       1 controller.go:854] volume "pvc-5dee4db8-b6d1-4a63-baf5-b5ff8eae6ecb" provisioned for claim "default/test-claim"

######### 登陆pod：查看写入的文件#########
[root@master user-pv]# kubectl exec -it test-pod sh
/ # ls 
bin   dev   etc   home  mnt   proc  root  sys   tmp   usr   var
/ # ls /mnt/
SUCCESS
/ # cat /mnt/SUCCESS 
auto-pvc

######### 登陆nfs服务器：查看写入的文件#########
[root@master ~]# ssh docker
Warning: Permanently added 'docker,192.168.56.201' (RSA) to the list of known hosts.
Last login: Wed Sep 25 11:57:48 2019 from 192.168.56.1

[root@docker ~]# cat /data/nfs/kubernetes/default-test-claim-pvc-5dee4db8-b6d1-4a63-baf5-b5ff8eae6ecb/SUCCESS
auto-pvc