011.Kubernetes使用共享存储持久化数据

dayi 2020-01-18

本次实验是以前面的实验为基础,使用的是模拟使用kubernetes集群部署一个企业版的wordpress为实例进行研究学习,主要的过程如下:

1.mysql deployment部署, wordpress deployment部署, wordpress连接mysql时,mysql的 pod ip易变

2.为mysql创建 service,申请固定 service lp

3. wordpress外部可访问,使用 node port类型的 service

4. nodeport类型的 service需要映射端口,不是很优雅

5.使用 ingressl

6.mysq1的pod旦被重新调度,数据就会丢失

7. hostpath将pod数据挂载至本地,然后使用标签选择器将mysq1lpod固定在一个节点上

8.共享存储以持久化数据,即使po挂掉,被重新拉起,也能自动挂载存储

本次实验解决使用共享存储数据持久化的问题实验使用NFS作为共享存储

一 使用NFS共享存储

1.1 安装NFS

再server3和server1上安装nfs

[ ~]# yum -y install nfs-utils

[ ~]# yum -y install nfs-utils

[ ~]# vi /etc/exports

/data *(rw,no_root_squash)

[ ~]# systemctl restart nfs

[ ~]# systemctl status nfs

011.Kubernetes使用共享存储持久化数据

[ ~]# showmount -e

Export list for docker-server3:
/data *

1.2 到server1上进行挂载测试

[ ~]# mount -t nfs 192.168.132.133:/data /mnt

[ ~]# df -hT

192.168.132.133:/data   nfs4       47G  7.3G   40G  16% /mnt

[ ~]# umount /mnt/

nfs配置成功

1.3 数据库使用共享存储挂载卷

[ ~]# mkdir /data/mysql

[ deployment]# vi mysql-deployment.yaml

apiVersion:  apps/v1
kind: Deployment
metadata:
  name: mysql
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: mysql
  template:
    metadata:
      labels:
        app: mysql
    spec:
      volumes:
        - name: mydata
          nfs:
            server: 192.168.132.133
            path: /data/mysql
      containers:
        - name: mysql
          image: mysql:5.7
          volumeMounts:
            - name: mydata
              mountPath: /var/lib/mysql
          ports:
            - containerPort: 3306
          env:
            - name: MYSQL_ROOT_PASSWORD
              value: RedHat123
            - name: MYSQL_DATABASE
              value: wordpress

[ deployment]# kubectl get pods -o wide

mysql-857589b5d4-j65d2              1/1     Running   0          20s     10.244.2.20   192.168.132.133   <none>

[ ~]# ll /data/mysql

-rw-r----- 1 polkitd ssh_keys       56 Jan 17 22:29 auto.cnf
-rw------- 1 polkitd ssh_keys     1676 Jan 17 22:29 ca-key.pem
-rw-r--r-- 1 polkitd ssh_keys     1112 Jan 17 22:29 ca.pem
-rw-r--r-- 1 polkitd ssh_keys     1112 Jan 17 22:29 client-cert.pem
-rw------- 1 polkitd ssh_keys     1680 Jan 17 22:29 client-key.pem
-rw-r----- 1 polkitd ssh_keys     1346 Jan 17 22:29 ib_buffer_pool
-rw-r----- 1 polkitd ssh_keys 79691776 Jan 17 22:29 ibdata1
-rw-r----- 1 polkitd ssh_keys 50331648 Jan 17 22:29 ib_logfile0
-rw-r----- 1 polkitd ssh_keys 50331648 Jan 17 22:29 ib_logfile1
-rw-r----- 1 polkitd ssh_keys 12582912 Jan 17 22:30 ibtmp1
drwxr-x--- 2 polkitd ssh_keys     4096 Jan 17 22:29 mysql
drwxr-x--- 2 polkitd ssh_keys     8192 Jan 17 22:29 performance_schema
-rw------- 1 polkitd ssh_keys     1680 Jan 17 22:29 private_key.pem
-rw-r--r-- 1 polkitd ssh_keys      452 Jan 17 22:29 public_key.pem
-rw-r--r-- 1 polkitd ssh_keys     1112 Jan 17 22:29 server-cert.pem
-rw------- 1 polkitd ssh_keys     1680 Jan 17 22:29 server-key.pem
drwxr-x--- 2 polkitd ssh_keys     8192 Jan 17 22:29 sys
drwxr-x--- 2 polkitd ssh_keys       20 Jan 17 22:29 wordpress

这样,房mysql的pod是被删除的时候,数据不会丢失

这种方式,可以满足效果,但是当直接对接不同的存储,需要使用不同的对接格式,对于K8S而言,不方便,所以使用PV的格式挂载,即不管使用哪一种存储方式,最终创建一个PV出来,然后K8S直接挂载PV,不用关心底层是哪一种存储

二 持久化卷(PV)

2.1 PV及PVC介绍

PersistentVolume (PV) 和 PersistentVolumeClaim (PVC) 提供了方便的持久化卷:PV 提供网络存储资源,而 PVC 请求存储资源。这样,设置持久化的工作流包括配置底层文件系统或者云数据卷、创建持久性数据卷、最后创建 PVC 来将 Pod 跟数据卷关联起来。PV 和 PVC 可以将 pod 和数据卷解耦,pod 不需要知道确切的文件系统或者支持它的持久化引擎。

PersistentVolume(PV)是集群之中的一块网络存储。跟 Node 一样,也是集群的资源。PV 跟 Volume (卷) 类似,不过会有独立于 Pod 的生命周期

1.为了屏蔽 kubernetes对底层存储的差异,有了个申明称之为pv

2. pod在创建时,只需要声明需要一个pV即可,这

3. 创建pv:

  1. 大小10G
  2. 独享还是共享
  3. 从哪种存储申请

4. 创建pvc:

  1. 大小20G
  2. 独享还是共享

2.2 创建一个PV

基于NFS创建PV

[ yamls]# mkdir /yamls/storage

[ yamls]# cd /yamls/storage

[ storage]# vim pv1.yaml

apiVersion: v1
kind: PersistentVolume
metadata: 
  name: pv1
spec:
  capacity:
    storage: 1G
  accessModes:
    - ReadWriteMany
  nfs:
    server: 192.168.132.133
    path: "/data"

[ storage]# kubectl apply -f pv1.yaml   

[ storage]# kubectl get pv

NAME   CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS   REASON   AGE
pv1    1G         RWX            Retain           Available                                   23s

RECLAIM POLICY回收策略

PV的回收策略(persistentVolumeReclaimPolicy,即PVC释放卷的时候PV该如何操作)也有三种

  • Retain,不清理, 保留Volume(需要手动清理)
  • Recycle,删除数据,即rm -rf /thevolume/*(只有NFS和HostPath支持)
  • Delete,删除存储资源,比如删除AWS EBS卷(只有AWS EBS, GCE PD, Azure Disk和Cinder支持)

2.3 创建一个PVC

[ storage]# vim pvc1.yaml

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: pvc1
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 1Gi

[ storage]# kubectl apply -f pvc1.yaml

persistentvolumeclaim/pvc1 created

[ storage]# kubectl get pvc -n kube-system

No resources found in kube-system namespace.    #pvc只有在创建的命名空间看到

[ storage]# kubectl get pv -n kube-system

NAME   CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS   REASON   AGE
pv1    1G         RWX            Retain           Available                                   8m56s

[ storage]# kubectl get pvc 

NAME   STATUS    VOLUME   CAPACITY   ACCESS MODES   STORAGECLASS   AGE
pvc1   Pending                                                     2m8s

[ storage]# kubectl describe pvc pvc1

Name:          pvc1
Namespace:     default
StorageClass:  
Status:        Pending
Volume:        
Labels:        <none>
Annotations:   kubectl.kubernetes.io/last-applied-configuration:
                 {"apiVersion":"v1","kind":"PersistentVolumeClaim","metadata":{"annotations":{},"name":"pvc1","namespace":"default"},"spec":{"accessModes":...
Finalizers:    [kubernetes.io/pvc-protection]
Capacity:      
Access Modes:  
VolumeMode:    Filesystem
Mounted By:    <none>
Events:
  Type    Reason         Age                  From                         Message
  ----    ------         ----                 ----                         -------
  Normal  FailedBinding  7s (x15 over 3m22s)  persistentvolume-controller  no persistent volumes available for this claim and no storage class is set   #没有完全满足的pv可以绑定

这是因为pv是1G,PVC申请的是1Gi,修改如下

[ storage]# vi pvc1.yaml 

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: pvc1
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 1G

pvc资源只能删除重建

[ storage]# kubectl delete pvc pvc1

persistentvolumeclaim "pvc1" deleted

[ storage]# kubectl apply -f pvc1.yaml

persistentvolumeclaim/pvc1 created

[ storage]# kubectl get pvc

NAME   STATUS   VOLUME   CAPACITY   ACCESS MODES   STORAGECLASS   AGE
pvc1   Bound    pv1      1G         RWX                           5s

已经绑定

[ storage]# kubectl get pv

NAME   CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM          STORAGECLASS   REASON   AGE
pv1    1G         RWX            Retain           Bound    default/pvc1                           16m

2.4 mysql使用pvc绑定

[ ~]# mkdir /data/mysql11

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-rwo.yaml
spec:
  capacity:
    storage: 10G
  accessModes:
    - ReadWriteOnce
  nfs:
    server: 192.168.132.133
    path: "/data/mysql11"

[ storage]# kubectl apply -f pv-rwo.yaml

[ storage]# vi pvc-rwo.yaml

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: pvc-rwo
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10G

[ storage]# kubectl get pvc

NAME      STATUS   VOLUME        CAPACITY   ACCESS MODES   STORAGECLASS   AGE
pvc-rwo   Bound    pv-rwo.yaml   10G        RWO                           6s
pvc1      Bound    pv1           1G         RWX                           10m

[ storage]# kubectl get pv

NAME          CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM             STORAGECLASS   REASON   AGE
pv-rwo.yaml   10G        RWO            Retain           Bound    default/pvc-rwo                           101s
pv1           1G         RWX            Retain           Bound    default/pvc1                              24m

挂载到数据库

[ storage]# vim /yamls/deployment/mysql-deployment.yaml

apiVersion:  apps/v1
kind: Deployment
metadata:
  name: mysql
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: mysql
  template:
    metadata:
      labels:
        app: mysql
    spec:
     # volumes:
     #   - name: mydata
     #     nfs:
     #       server: 192.168.132.133
     #       path: /data/mysql
      volumes:
        - name: mydata
          persistentVolumeClaim:
            claimName: pvc-rwo
      containers:
        - name: mysql
          image: mysql:5.7
          volumeMounts:
            - name: mydata
              mountPath: /var/lib/mysql
          ports:
            - containerPort: 3306
          env:
            - name: MYSQL_ROOT_PASSWORD
              value: RedHat123
            - name: MYSQL_DATABASE
              value: wordpress

[ storage]# kubectl apply -f /yamls/deployment/mysql-deployment.yaml

[ ~]# ll /data/mysql11

total 188484
-rw-r----- 1 polkitd ssh_keys       56 Jan 18 00:46 auto.cnf
-rw------- 1 polkitd ssh_keys     1676 Jan 18 00:46 ca-key.pem
-rw-r--r-- 1 polkitd ssh_keys     1112 Jan 18 00:46 ca.pem
-rw-r--r-- 1 polkitd ssh_keys     1112 Jan 18 00:46 client-cert.pem
-rw------- 1 polkitd ssh_keys     1680 Jan 18 00:46 client-key.pem
-rw-r----- 1 polkitd ssh_keys     1346 Jan 18 00:46 ib_buffer_pool
-rw-r----- 1 polkitd ssh_keys 79691776 Jan 18 00:46 ibdata1
-rw-r----- 1 polkitd ssh_keys 50331648 Jan 18 00:46 ib_logfile0
-rw-r----- 1 polkitd ssh_keys 50331648 Jan 18 00:46 ib_logfile1
-rw-r----- 1 polkitd ssh_keys 12582912 Jan 18 00:46 ibtmp1
drwxr-x--- 2 polkitd ssh_keys     4096 Jan 18 00:46 mysql
drwxr-x--- 2 polkitd ssh_keys     8192 Jan 18 00:46 performance_schema
-rw------- 1 polkitd ssh_keys     1680 Jan 18 00:46 private_key.pem
-rw-r--r-- 1 polkitd ssh_keys      452 Jan 18 00:46 public_key.pem
-rw-r--r-- 1 polkitd ssh_keys     1112 Jan 18 00:46 server-cert.pem
-rw------- 1 polkitd ssh_keys     1680 Jan 18 00:46 server-key.pem
drwxr-x--- 2 polkitd ssh_keys     8192 Jan 18 00:46 sys
drwxr-x--- 2 polkitd ssh_keys       20 Jan 18 00:46 wordpress

已经重建数据,则PV和PVC简单学习到这里


博主声明:本文的内容来源主要来自誉天教育晏威老师,由本人实验完成操作验证,需要的博友请联系誉天教育(http://www.yutianedu.com/),获得官方同意或者晏老师(https://www.cnblogs.com/breezey/)本人同意即可转载,谢谢!

011.Kubernetes使用共享存储持久化数据

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