第八章 Kubernetes进阶之Volume

　　Volume和PersistentVolume

　　数据卷和持久数据卷

　　1.Volume

　　kubernetes中的Volume提供了容器中挂载外部存储的能力

　　Pod需要设置卷来源(spec.volume)和挂载点（spec.containers.volumeMounts）两个信息后才能使用相应的Volume

　　官方参考文档：https://kubernetes.io/zh/docs/concepts/services-networking/ingress/

　　emptyDir

　　创建一个空卷，挂载到Pod中容器。Pod删除该卷也会被删除

　　应用场景：Pod容器间数据共享

　　示例

apiVersion: v1
kind: Pod
metadata:
  name: my-pod
spec:
  containers:
  - name: write
    image: centos
    command: ["bash","-c","for i in {1..100};do echo $i >> /data/hello;sleep 1;done"]
    volumeMounts:
      - name: data
        mountPath: /data
 
  - name: read
    image: centos
    command: ["bash","-c","tail -f /data/hello"]
    volumeMounts:
      - name: data
        mountPath: /data
 
  volumes:
  - name: data
    #创建空目录，挂载到对应容器的目录/data下
    emptyDir: {}

 　　定义两个容器一个写入，一个读取

　　应用

kubectl apply -f emptydir.yaml

 　　查看

# kubectl get pod
NAME                          READY   STATUS    RESTARTS   AGE
my-pod                        2/2     Running   0          2m20s
my-service-5575964984-zbmck   1/1     Running   0          4h46m

 　　登录对应容器查看

kubectl exec -it my-pod -c write bash
kubectl exec -it my-pod -c read bash

 　　查看是否在write写入，在read可以读取

tail -f /data/hello

 　　也可以不登录容器直接查看read日志

kubectl logs my-pod -c read -f

 　　在日志收集章节也会使用到该数据卷模式

　　hostPath

　　挂载Node文件系统上文件或者目录到Pod中容器

　　应用场景：Pod容器需要访问宿主机文件

　　示例

# cat hostpath.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: my-pod
spec:
  containers:
  - name: busybox
    image: busybox
    args:
    - /bin/sh
    - -c
    - sleep 36000
    volumeMounts:
    - name: data
      mountPath: /data
  volumes:
  - name: data
    hostPath:
      path: /tmp
      type: Directory

 　　查看一下该pod挂载到哪一个节点

# kubectl get pod -o wide
NAME                          READY   STATUS    RESTARTS   AGE    IP           NODE           NOMINATED NODE   READINESS GATES
my-pod                        1/1     Running   0          91s    172.17.9.3   192.168.1.65   <none>           <none>
my-service-5575964984-zbmck   1/1     Running   0          5h4m   172.17.9.2   192.168.1.65   <none>           <none>

 　　登录容器查看

kubectl exec -it my-pod  sh

 　　在对应的node 192.168.1.65的/tmp创建文件测试

touch test

 　　在登录的容器内查看

 # ls /data/
tes

　　2.PersisterVolume

　　以上介绍存储卷是挂载在本机上的，如果Pod重启以后宿主机可能会改变所以需要持久化需要挂载网络存储

　　以NFS网络存储为例 首先安装NFS，安装位置为192.168.1.61

　　安装参考：https://www.cnblogs.com/minseo/p/10026358.html

　　node端192.168.1.65 192.168.1.66也需要安装客户端用于挂载NFS

yum -y install nfs-utils

 　　服务端配置文件

# cat /etc/exports
/data/nfs *(rw,no_root_squash)

 　　启动nfs

systemctl restart nfs

 　　设置nfs配置yaml文件 nfs.yaml

apiVersion: apps/v1beta1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  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: 192.168.1.61
          path: /data/nfs

 　　应用

kubectl apply -f nfs.yaml 

 　　查看

# kubectl get pod
NAME                                READY   STATUS    RESTARTS   AGE
my-service-5575964984-zbmck         1/1     Running   0          5h54m
nginx-deployment-759484bc6d-jb97p   1/1     Running   0          73s
nginx-deployment-759484bc6d-ml4l8   1/1     Running   0          73s
nginx-deployment-759484bc6d-t9f72   1/1     Running   0          73s

 　　进入其中一个容器

kubectl exec -it nginx-deployment-759484bc6d-ml4l8 bash

 　　查看目录为空

/usr/share/nginx/html

 　　然后在nfs主机创建一个文档index.html内容是Hello World

　　创建一个svc对应该deployment

kubectl expose deployment nginx-deployment --port=80 --target-port=80 --type=NodePort

 　　查看

# kubectl get svc
NAME               TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
kubernetes         ClusterIP   10.0.0.1     <none>        443/TCP        23h
my-service         NodePort    10.0.0.130   <none>        80:42291/TCP   5h59m
nginx-deployment   NodePort    10.0.0.42    <none>        80:37946/TCP   3s

 　　页面访问测试

 　　使用其他pod挂载该数据会一直存在，不会因为Pod挂掉重启而丢失

　　使用glusterfs作为pv

　　NFS是单点存储可能会出现单点故障，可以使用分布式glusterfs作为存储

　　参考：https://github.com/kubernetes/examples/tree/master/volumes/glusterfs

　　　　需要先配置glusterfs分布式存储

             安装glusterfs参考https://www.cnblogs.com/minseo/p/6919421.html

　　　　本次已经安装glusterfs节点为192.168.1.61和192.168.1.62挂载点为/gv1

 　　　　下载yaml文件

# cat glusterfs-endpoints.yaml 
apiVersion: v1
kind: Endpoints
metadata:
  name: glusterfs-cluster
subsets:
- addresses:
  #glusterfs节点，端口自定义
  #glusterfs-service.yaml需要配置此端口
  - ip: 192.168.1.61
  ports:
  - port: 1
- addresses:
  - ip: 192.168.1.62
  ports:
  - port: 1

# cat glusterfs-service.yaml 
apiVersion: v1
kind: Service
metadata:
  name: glusterfs-cluster
spec:
  ports:
  - port: 1

# cat glusterfs-pod.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: glusterfs
spec:
  containers:
  - name: glusterfs
    image: nginx
    volumeMounts:
    - mountPath: "/mnt/glusterfs"
      name: glusterfsvol
  volumes:
  - name: glusterfsvol
    #创建的卷类型是glusterfs
    glusterfs:
      endpoints: glusterfs-cluster
      #创建glusterfs定义的卷名本次为gv1
      path: gv1
      readOnly: true

 　　创建

kubectl apply -f .

 　　查看创建的ep pod svc

# kubectl get ep,pod,svc
NAME                          ENDPOINTS                       AGE
endpoints/glusterfs-cluster   192.168.1.61:1,192.168.1.62:1   48m
endpoints/kubernetes          192.168.1.63:6443               12d
NAME                                        READY   STATUS    RESTARTS   AGE
pod/glusterfs                               1/1     Running   0          42m

NAME                        TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
service/glusterfs-cluster   ClusterIP   10.0.0.158   <none>        1/TCP     47m

 　　登录容器查看

# kubectl exec -it glusterfs bash
#容器内挂载目录是/mnt/glusterfs/
cd /mnt/glusterfs/
#查看该目录下的文件和glusterfs对应目录文件是一致

　　3.PersisterVolume动态供给

　　nfs动态供给

　　前提条件：部署好NFS服务器

　　部署NFS服务器参考：https://www.cnblogs.com/minseo/p/10026358.html

　　下载NFS动态供给yaml配置文件

　　下载地址https://github.com/kubernetes-incubator/external-storage/tree/master/nfs-client/deploy

　　下载一下3个yaml配置文件

# cat class.yaml 
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  #应用使用哪一个class创建PV
  name: managed-nfs-storage
provisioner: fuseim.pri/ifs # or choose another name, must match deployment's env PROVISIONER_NAME'
parameters:
  archiveOnDelete: "false"

# cat 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: ["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

 　　delpoyment.yaml需要修改配置nfs地址及路径

# cat 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: 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: 192.168.1.61
            - name: NFS_PATH
              value: /ifs/kubernetes
      volumes:
        - name: nfs-client-root
          nfs:
            server: 192.168.1.61
            path: /ifs/kubernetes

 

 　　创建

# kubectl apply -f .
storageclass.storage.k8s.io/managed-nfs-storage created
deployment.apps/nfs-client-provisioner created
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

 　　查看创建的pod和deploy

# kubectl get pod
NAME                                    READY   STATUS    RESTARTS   AGE
nfs-client-provisioner-7db87779-bcn6j   1/1     Running   0          92s
[root@localhost nfs]# kubectl get deploy
NAME                     READY   UP-TO-DATE   AVAILABLE   AGE
nfs-client-provisioner   1/1     1            1           95s

 　　查看创建的 storageclass名为managed-nfs-storage

# kubectl get storageclass
NAME                  PROVISIONER      RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
managed-nfs-storage   fuseim.pri/ifs   Delete          Immediate           false                  2m21s

 　　创建PVC

# cat test-claim.yaml 
apiVersion: v1
#创建pvc名称为test-claim
kind: PersistentVolumeClaim
metadata:
  name: test-claim
spec:
  #ReadWriteMany可读写并且可以被多个节点使用
  #ReadWriteOnce只能被一个节点使用
  #ReadOnlyMany可以被多个节点读取
  accessModes:
    - ReadWriteMany
  #对应的storageClass名
  storageClassName: "managed-nfs-storage"
  #定义动态分配存储空间大小为10M
  resources:
    requests:
      storage: 10Mi

 　　

# kubectl apply -f test-claim.yaml 
persistentvolumeclaim/test-claim created

 　　查看创建的pvc

# kubectl get pvc 
NAME             STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS          AGE
test-claim       Bound    pvc-6de65f62-e92f-4a44-85f2-271637e45ce9   10Mi       RWX            managed-nfs-storage   38s

 　　NFS服务器对应的共享目录生成一个对应pvc文件夹

 　　创建一个Pod挂载对应的pvc

# cat test-pod.yaml 
kind: Pod
apiVersion: v1
metadata:
  name: test-pod
spec:
  containers:
  - name: test-pod
    image: busybox:1.24
    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 apply -f test-pod.yaml 
pod/test-pod created

 　　该Pod把对应的pvc挂载在容器目录/mnt并且在该目录创建一个文件SUCCESS，执行完毕处于 Completed状态

 　　在NFS服务器对应目录可以看到创建的文件SUCESS

 　　测试其他Pod挂载

# cat test-pod2.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: test-pod2
spec:
  containers:
  - name: nginx
    image: nginx
    volumeMounts:
      - name: nfs-pvc
        mountPath: "/mnt"
  volumes:
    - name: nfs-pvc
      persistentVolumeClaim:
        claimName: test-claim

 　　

# kubectl apply -f test-pod2.yaml 
pod/test-pod2 created

 　　登录pod查看目录

# kubectl exec -it test-pod2 bash
root@test-pod2:/# ls /mnt
SUCCESS

 　　该Pod挂载的pvc也是test-claim所以对应目录的文件是一样的

　　glusterfs动态供给

 　　参考：https://www.cnblogs.com/minseo/p/12575604.html