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NFS简介
NFS是网络文件系统Network File System的缩写，NFS服务器可以让PC将网络中的NFS服务器共享的目录挂载到本地的文件系统中，而在本地的系统中来看，那个远程主机的目录就好像是自己的一个磁盘分区一样。
kubernetes使用NFS共享存储有两种方式：
- 1.手动方式静态创建所需要的PV和PVC。
- 2.通过创建PVC动态地创建对应PV，无需手动创建PV。
下面对这两种方式进行配置并进行演示。
搭建NFS服务器
k8s集群准备，以这篇文章为例：https://blog.csdn.net/networken/article/details/84991940
这里作为测试，临时在master节点上部署NFS服务器。
#master节点安装nfs
yum -y install nfs-utils
#创建nfs目录
mkdir -p /nfs/data/*
#修改权限
chmod -R 777 /nfs/data
#编辑export文件
vim /etc/exports
/nfs/data *(rw,no_root_squash,sync)
#配置生效
exportfs -r
#查看生效
exportfs
#启动rpcbind、nfs服务
systemctl restart rpcbind && systemctl enable rpcbind
systemctl restart nfs && systemctl enable nfs
#查看 RPC 服务的注册状况
rpcinfo -p localhost
#showmount测试
showmount -e 192.168.92.56
#所有node节点安装客户端
yum -y install nfs-utils
systemctl start nfs && systemctl enable nfs
作为准备工作，我们已经在 k8s-master 节点上搭建了一个 NFS 服务器，目录为 /nfs/data.
静态申请PV卷
添加pv卷对应目录,这里创建2个pv卷，则添加2个pv卷的目录作为挂载点。
#创建pv卷对应的目录
mkdir -p /nfs/data/pv001
mkdir -p /nfs/data/pv002
#配置exportrs
vim /etc/exports
/nfs/data *(rw,no_root_squash,sync)
/nfs/data/pv001 *(rw,no_root_squash,sync)
/nfs/data/pv002 *(rw,no_root_squash,sync)
#配置生效
exportfs -r
#重启rpcbind、nfs服务
systemctl restart rpcbind && systemctl restart nfs
创建PV
下面创建2个名为pv001和pv002的PV卷，配置文件 nfs-pv001.yaml 如下：
[centos@k8s-master ~]$ vim nfs-pv001.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: nfs-pv001
labels:
pv: nfs-pv001
spec:
capacity:
storage: 1Gi
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Recycle
storageClassName: nfs
nfs:
path: /nfs/data/pv001
server: 192.168.92.56
nfs-pv002.yaml文件如下：
[centos@k8s-master ~]$ vim nfs-pv001.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: nfs-pv002
labels:
pv: nfs-pv002
spec:
capacity:
storage: 1Gi
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Recycle
storageClassName: nfs
nfs:
path: /nfs/data/pv002
server: 192.168.92.56
配置说明：
① capacity 指定 PV 的容量为 1G。
② accessModes 指定访问模式为 ReadWriteOnce，支持的访问模式有：
- ReadWriteOnce – PV 能以 read-write 模式 mount 到单个节点。
- ReadOnlyMany – PV 能以 read-only 模式 mount 到多个节点。
- ReadWriteMany – PV 能以 read-write 模式 mount 到多个节点。
③ persistentVolumeReclaimPolicy 指定当 PV 的回收策略为 Recycle，支持的策略有：
- Retain – 需要管理员手工回收。
- Recycle – 清除 PV 中的数据，效果相当于执行 rm -rf /thevolume/*。
- Delete – 删除 Storage Provider 上的对应存储资源，例如 AWS EBS、GCE PD、Azure
Disk、OpenStack Cinder Volume 等。
④ storageClassName 指定 PV 的 class 为 nfs。相当于为 PV 设置了一个分类，PVC 可以指定 class 申请相应 class 的 PV。
⑤ 指定 PV 在 NFS 服务器上对应的目录。
创建 pv：
[centos@k8s-master ~]$ kubectl apply -f nfs-pv001.yaml
persistentvolume/nfs-pv001 created
[centos@k8s-master ~]$ kubectl apply -f nfs-pv002.yaml
persistentvolume/nfs-pv002 created
[centos@k8s-master ~]$ kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
nfs-pv001 1Gi RWO Recycle Available nfs 4s
nfs-pv002 1Gi RWO Recycle Available nfs 2s
[centos@k8s-master ~]$
STATUS 为 Available，表示 pv就绪，可以被 PVC 申请。
创建PVC
接下来创建一个名为pvc001和pvc002的PVC，配置文件 nfs-pvc001.yaml 如下：
[centos@k8s-master ~]$ vim nfs-pvc001.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: nfs-pvc001
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
storageClassName: nfs
selector:
matchLabels:
pv: nfs-pv001
nfs-pvc002.yaml配置文件
[centos@k8s-master ~]$ vim nfs-pvc001.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: nfs-pvc002
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
storageClassName: nfs
selector:
matchLabels:
pv: nfs-pv002
执行yaml文件创建 pvc：
[centos@k8s-master ~]$ kubectl apply -f nfs-pvc001.yaml
persistentvolumeclaim/nfs-pvc001 created
[centos@k8s-master ~]$ kubectl apply -f nfs-pvc002.yaml
persistentvolumeclaim/nfs-pvc002 created
[centos@k8s-master ~]$ kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
nfs-pvc001 Bound pv001 1Gi RWO nfs 6s
nfs-pvc002 Bound pv002 1Gi RWO nfs 3s
[centos@k8s-master ~]$ kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
nfs-pv001 1Gi RWO Recycle Bound default/pvc001 nfs 9m12s
nfs-pv002 1Gi RWO Recycle Bound default/pvc002 nfs 9m10s
[centos@k8s-master ~]$
从 kubectl get pvc 和 kubectl get pv 的输出可以看到 pvc001 和pvc002分别绑定到pv001和pv002，申请成功。注意pvc绑定到对应pv通过labels标签方式实现，也可以不指定，将随机绑定到pv。
接下来就可以在 Pod 中使用存储了，Pod 配置文件 nfs-pod001.yaml 如下：
[centos@k8s-master ~]$ vim nfs-pod001.yaml
kind: Pod
apiVersion: v1
metadata:
name: nfs-pod001
spec:
containers:
- name: myfrontend
image: nginx
volumeMounts:
- mountPath: "/var/www/html"
name: nfs-pv001
volumes:
- name: nfs-pv001
persistentVolumeClaim:
claimName: nfs-pvc001
nfs-pod002.yaml 如下：
[centos@k8s-master ~]$ vim nfs-pod002.yaml
kind: Pod
apiVersion: v1
metadata:
name: nfs-pod002
spec:
containers:
- name: myfrontend
image: nginx
volumeMounts:
- mountPath: "/var/www/html"
name: nfs-pv002
volumes:
- name: nfs-pv002
persistentVolumeClaim:
claimName: nfs-pvc002
与使用普通 Volume 的格式类似，在 volumes 中通过 persistentVolumeClaim 指定使用nfs-pvc001和nfs-pvc002申请的 Volume。
执行yaml文件创建nfs-pdo001和nfs-pod002：
[centos@k8s-master ~]$ kubectl apply -f nfs-pod001.yaml
pod/nfs-pod001 created
[centos@k8s-master ~]$ kubectl apply -f nfs-pod002.yaml
pod/nfs-pod002 created
[centos@k8s-master ~]$ kubectl get pod
NAME READY STATUS RESTARTS AGE
nfs-client-provisioner-75bf876d88-sqqpv 1/1 Running 0 25m
nfs-pod001 1/1 Running 0 12s
nfs-pod002 1/1 Running 0 9s
[centos@k8s-master ~]$
验证 PV 是否可用：
[centos@k8s-master ~]$ kubectl exec nfs-pod001 touch /var/www/html/index001.html
[centos@k8s-master ~]$ kubectl exec nfs-pod002 touch /var/www/html/index002.html
[centos@k8s-master ~]$ ls /nfs/data/pv001/
index001.html
[centos@k8s-master ~]$ ls /nfs/data/pv002/
index002.html
[centos@k8s-master ~]$
进入pod查看挂载情况
[centos@k8s-master ~]$ kubectl exec -it nfs-pod001 /bin/bash
root@nfs-pod001:/# df -h
......
192.168.92.56:/nfs/data/pv001 47G 5.2G 42G 11% /var/www/html
......
root@nfs-pod001:/#
删除pv
删除pod，pv和pvc不会被删除，nfs存储的数据不会被删除。
[centos@k8s-master ~]$ kubectl delete -f nfs-pod001.yaml
pod "nfs-pod001" deleted
[centos@k8s-master ~]$ kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
nfs-pv001 1Gi RWO Recycle Bound default/pvc001 nfs 34m
nfs-pv002 1Gi RWO Recycle Bound default/pvc002 nfs 34m
[centos@k8s-master ~]$ kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
nfs-pvc001 Bound pv001 1Gi RWO nfs 25m
nfs-pvc002 Bound pv002 1Gi RWO nfs 25m
[centos@k8s-master ~]$ ls /nfs/data/pv001/
index001.html
[centos@k8s-master ~]$
继续删除pvc，pv将被释放，处于 Available 可用状态，并且nfs存储中的数据被删除。
[centos@k8s-master ~]$ kubectl delete -f nfs-pvc001.yaml
persistentvolumeclaim "nfs-pvc001" deleted
[centos@k8s-master ~]$ kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
nfs-pv001 1Gi RWO Recycle Available nfs 35m
nfs-pv002 1Gi RWO Recycle Bound default/pvc002 nfs 35m
[centos@k8s-master ~]$ ls /nfs/data/pv001/
[centos@k8s-master ~]$
继续删除pv
[centos@k8s-master ~]$ kubectl delete -f nfs-pv001.yaml
persistentvolume "pv001" deleted
动态申请PV卷
项目地址：
https://github.com/kubernetes-incubator/external-storage/tree/master/nfs-client
External NFS驱动的工作原理
K8S的外部NFS驱动，可以按照其工作方式（是作为NFS server还是NFS client）分为两类：
1.nfs-client:
也就是我们接下来演示的这一类，它通过K8S的内置的NFS驱动挂载远端的NFS服务器到本地目录；然后将自身作为storage provider，关联storage class。当用户创建对应的PVC来申请PV时，该provider就将PVC的要求与自身的属性比较，一旦满足就在本地挂载好的NFS目录中创建PV所属的子目录，为Pod提供动态的存储服务。
2.nfs:
与nfs-client不同，该驱动并不使用k8s的NFS驱动来挂载远端的NFS到本地再分配，而是直接将本地文件映射到容器内部，然后在容器内使用ganesha.nfsd来对外提供NFS服务；在每次创建PV的时候，直接在本地的NFS根目录中创建对应文件夹，并export出该子目录。
利用NFS动态提供Kubernetes后端存储卷
本文将介绍使用nfs-client-provisioner这个应用，利用NFS Server给Kubernetes作为持久存储的后端，并且动态提供PV。前提条件是有已经安装好的NFS服务器，并且NFS服务器与Kubernetes的Slave节点都能网络连通。将nfs-client驱动做一个deployment部署到K8S集群中，然后对外提供存储服务。
nfs-client-provisioner 是一个Kubernetes的简易NFS的外部provisioner，本身不提供NFS，需要现有的NFS服务器提供存储
部署nfs-client-provisioner
首先克隆仓库获取yaml文件
git clone https://github.com/kubernetes-incubator/external-storage.git
cp -R external-storage/nfs-client/deploy/ $HOME
cd deploy
修改deployment.yaml文件
这里修改的参数包括NFS服务器所在的IP地址（192.168.92.56），以及NFS服务器共享的路径（/nfs/data），两处都需要修改为你实际的NFS服务器和共享目录。另外修改nfs-client-provisioner镜像从dockerhub拉取。
[centos@k8s-master deploy]$ vim deployment.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: willdockerhub/nfs-client-provisioner:latest
volumeMounts:
- name: nfs-client-root
mountPath: /persistentvolumes
env:
- name: PROVISIONER_NAME
value: fuseim.pri/ifs
- name: NFS_SERVER
value: 192.168.92.56
- name: NFS_PATH
value: /nfs/data
volumes:
- name: nfs-client-root
nfs:
server: 192.168.92.56
path: /nfs/data
部署deployment.yaml
kubectl apply -f deployment.yaml
查看创建的POD
[centos@k8s-master ~]$ kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nfs-client-provisioner-75bf876d88-578lg 1/1 Running 0 51m 10.244.2.131 k8s-node2 <none> <none>
创建StorageClass
storage class的定义，需要注意的是：provisioner属性要等于驱动所传入的环境变量PROVISIONER_NAME的值。否则，驱动不知道知道如何绑定storage class。
此处可以不修改，或者修改provisioner的名字，需要与上面的deployment的PROVISIONER_NAME名字一致。
[centos@k8s-master deploy]$ vim 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"
部署yaml文件
kubectl apply -f class.yaml
查看创建的storageclass
[centos@k8s-master deploy]$ kubectl get sc
NAME PROVISIONER AGE
managed-nfs-storage fuseim.pri/ifs 95m
[centos@k8s-master deploy]$
配置授权
如果集群启用了RBAC，则必须执行如下命令授权provisioner。
[centos@k8s-master deploy]$ vim rbac.yaml
- 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
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
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
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
部署yaml文件
kubectl create -f rbac.yaml
测试
创建测试PVC
kubectl create -f test-claim.yaml
这里指定了其对应的storage-class的名字为managed-nfs-storage，如下：
[centos@k8s-master deploy]$ vim test-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
查看创建的PVC
可以看到PVC状态为Bound，绑定的volume为pvc-a17d9fd5-237a-11e9-a2b5-000c291c25f3。
[centos@k8s-master deploy]$ kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
test-claim Bound pvc-a17d9fd5-237a-11e9-a2b5-000c291c25f3 1Mi RWX managed-nfs-storage 34m
[centos@k8s-master deploy]$
查看自动创建的PV
[centos@k8s-master deploy]$ kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pvc-a17d9fd5-237a-11e9-a2b5-000c291c25f3 1Mi RWX Delete Bound default/test-claim managed-nfs-storage 34m
[centos@k8s-master deploy]$
然后，我们进入到NFS的export目录，可以看到对应该volume name的目录已经创建出来了。
其中volume的名字是namespace，PVC name以及uuid的组合：
[root@k8s-master ~]# cd /nfs/data/
[root@k8s-master data]# ll
total 0
drwxrwxrwx 2 root root 21 Jan 29 12:03 default-test-claim-pvc-a17d9fd5-237a-11e9-a2b5-000c291c25f3
创建测试Pod
指定该pod使用我们刚刚创建的PVC：test-claim，另外注意这里将镜像改为dockerhub镜像。
完成之后，如果attach到pod中执行一些文件的读写操作，就可以确定pod的/mnt已经使用了NFS的存储服务了。
[centos@k8s-master deploy]$ vim test-pod.yaml
kind: Pod
apiVersion: v1
metadata:
name: test-pod
spec:
containers:
- name: test-pod
image: willdockerhub/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
执行yaml文件
kubectl create -f test-pod.yaml
查看创建的测试POD
[centos@k8s-master ~]$ kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nfs-client-provisioner-75bf876d88-578lg 1/1 Running 0 51m 10.244.2.131 k8s-node2 <none> <none>
test-pod 0/1 Completed 0 41m 10.244.1.129 k8s-node1 <none> <none>
在NFS服务器上的共享目录下的卷子目录中检查创建的NFS PV卷下是否有"SUCCESS" 文件。
[root@k8s-master ~]# cd /nfs/data/
[root@k8s-master data]# ll
total 0
drwxrwxrwx 2 root root 21 Jan 29 12:03 default-test-claim-pvc-a17d9fd5-237a-11e9-a2b5-000c291c25f3
[root@k8s-master data]#
[root@k8s-master data]# cd default-test-claim-pvc-a17d9fd5-237a-11e9-a2b5-000c291c25f3/
[root@k8s-master default-test-claim-pvc-a17d9fd5-237a-11e9-a2b5-000c291c25f3]# ll
total 0
-rw-r--r-- 1 root root 0 Jan 29 12:03 SUCCESS
清理测试环境
删除测试POD
kubectl delete -f test-pod.yaml
删除测试PVC
kubectl delete -f test-claim.yaml
在NFS服务器上的共享目录下查看NFS的PV卷已经被删除。
官方wordpress示例
官方链接：
https://kubernetes.io/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/
创建secret
创建secret以存储mysql数据库密码，这里数据库登录密码设为123456
kubectl create secret generic mysql-pass --from-literal=password=123456
查看创建的secret
[centos@k8s-master ~]$ kubectl get secrets
NAME TYPE DATA AGE
mysql-pass Opaque 1 68m
[centos@k8s-master ~]$
部署MYSQL
MYSQL容器挂载持久卷到容器/var/lib/mysql目录下，其中MYSQL_ROOT_PASSWORD环境变量通过Secret方式设置数据库密码。
注意这里在官方示例基础上做了3处修改：
1.PersistentVolumeClaim中增加了如下内容
annotations:
volume.beta.kubernetes.io/storage-class: “managed-nfs-storage”
2.存储改为1Gi仅用来测试
3.msyql镜像改为mysql:latest
[centos@k8s-master ~]$ vim wordpress-mysql.yaml
apiVersion: v1
kind: Service
metadata:
name: wordpress-mysql
labels:
app: wordpress
spec:
ports:
- port: 3306
selector:
app: wordpress
tier: mysql
clusterIP: None
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: mysql-pv-claim
annotations:
volume.beta.kubernetes.io/storage-class: "managed-nfs-storage"
labels:
app: wordpress
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
---
apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
name: wordpress-mysql
labels:
app: wordpress
spec:
selector:
matchLabels:
app: wordpress
tier: mysql
strategy:
type: Recreate
template:
metadata:
labels:
app: wordpress
tier: mysql
spec:
containers:
- image: mysql:latest
name: mysql
env:
- name: MYSQL_ROOT_PASSWORD
valueFrom:
secretKeyRef:
name: mysql-pass
key: password
ports:
- containerPort: 3306
name: mysql
volumeMounts:
- name: mysql-persistent-storage
mountPath: /var/lib/mysql
volumes:
- name: mysql-persistent-storage
persistentVolumeClaim:
claimName: mysql-pv-claim
部署wordpress
注意这里同样在官方示例基础上做了4处修改：
1.Service项的类型改为NodePort
type: NodePort
2.PersistentVolumeClaim中增加了如下内容
annotations:
volume.beta.kubernetes.io/storage-class: “managed-nfs-storage”
3.存储改为1Gi仅用来测试
4.wordpress镜像改为wordpress:latest
[centos@k8s-master ~]$ vim wordpress.yaml
apiVersion: v1
kind: Service
metadata:
name: wordpress
labels:
app: wordpress
spec:
ports:
- port: 80
selector:
app: wordpress
tier: frontend
type: NodePort
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: wp-pv-claim
annotations:
volume.beta.kubernetes.io/storage-class: "managed-nfs-storage"
labels:
app: wordpress
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
---
apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
name: wordpress
labels:
app: wordpress
spec:
selector:
matchLabels:
app: wordpress
tier: frontend
strategy:
type: Recreate
template:
metadata:
labels:
app: wordpress
tier: frontend
spec:
containers:
- image: wordpress:latest
name: wordpress
env:
- name: WORDPRESS_DB_HOST
value: wordpress-mysql
- name: WORDPRESS_DB_PASSWORD
valueFrom:
secretKeyRef:
name: mysql-pass
key: password
ports:
- containerPort: 80
name: wordpress
volumeMounts:
- name: wordpress-persistent-storage
mountPath: /var/www/html
volumes:
- name: wordpress-persistent-storage
persistentVolumeClaim:
claimName: wp-pv-claim
修改mysql连接认证方式
mysql8.0以上版本默认认证方式已经改为caching_sha2_password，wordpres等客户端还不支持，这里改回原来的mysql_native_password认证方式。(你也可以使用mysql:5.7.25等版本镜像避免此问题)。
#获取mysql容器所在pod名称
$ kubectl get pod
#进入mysql的pod
$ kubectl exec -it wordpress-mysql-5fd57746c7-8dhrq /bin/bash
#登录数据库（此处的密码为参数MYSQL_ROOT_PASSWORD对应的值，此处密码为123456）
mysql -u root -p
#使用mysql数据库
use mysql;
#查询mysql的root用户
mysql> select host, user, plugin from user;
+-----------+------------------+-----------------------+
| host | user | plugin |
+-----------+------------------+-----------------------+
| % | root | caching_sha2_password |
| localhost | mysql.infoschema | caching_sha2_password |
| localhost | mysql.session | caching_sha2_password |
| localhost | mysql.sys | caching_sha2_password |
| localhost | root | caching_sha2_password |
+-----------+------------------+-----------------------+
5 rows in set (0.00 sec)
#修改加密规则
ALTER USER 'root'@'%' IDENTIFIED BY 'password' PASSWORD EXPIRE NEVER;
#修改root用户插件验证方式，注意这里的密码，改为个人登录的密码
ALTER USER 'root'@'%' IDENTIFIED WITH mysql_native_password BY '123456';
#刷新权限
FLUSH PRIVILEGES;
查看创建的POD
[centos@k8s-master ~]$ kubectl get pod
NAME READY STATUS RESTARTS AGE
nfs-client-provisioner-75bf876d88-578lg 1/1 Running 2 9h
wordpress-8556476bc5-v79q2 1/1 Running 12 156m
wordpress-mysql-5fd57746c7-8dhrq 1/1 Running 0 13m
查看创建的PV和PVC
[centos@k8s-master ~]$ kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
mysql-pv-claim Bound pvc-a528b88f-23c7-11e9-9d07-000c291c25f3 1Gi RWO managed-nfs-storage 12m
wp-pv-claim Bound pvc-8f93dd7e-23b3-11e9-a2b5-000c291c25f3 1Gi RWO managed-nfs-storage 155m
[centos@k8s-master ~]$ kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pvc-8f93dd7e-23b3-11e9-a2b5-000c291c25f3 1Gi RWO Delete Bound default/wp-pv-claim managed-nfs-storage 155m
pvc-a528b88f-23c7-11e9-9d07-000c291c25f3 1Gi RWO Delete Bound default/mysql-pv-claim managed-nfs-storage 12m
[centos@k8s-master ~]$
查看wordpress service
[centos@k8s-master ~]$ kubectl get svc wordpress
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
wordpress NodePort 10.106.151.14 <none> 80:30533/TCP 157m
[centos@k8s-master ~]$
服务端口为30533，通过nodeport方式访问wordpress.
访问wordpress
http://192.168.92.56:30533
NFS端查看已创建的卷
卷目录下已写入持久化的mysql和wordpress配置数据，删除pod重新创建不会导致数据丢失。
[centos@k8s-master ~]$ cd /nfs/data/
[centos@k8s-master data]$ ll
total 8
drwxrwxrwx 7 polkitd ssh_keys 4096 Jan 29 21:16 default-mysql-pv-claim-pvc-a528b88f-23c7-11e9-9d07-000c291c25f3
drwxrwxrwx 5 root root 4096 Jan 29 21:16 default-wp-pv-claim-pvc-8f93dd7e-23b3-11e9-a2b5-000c291c25f3
[centos@k8s-master data]$
[centos@k8s-master data]$ cd default-mysql-pv-claim-pvc-a528b88f-23c7-11e9-9d07-000c291c25f3/
[centos@k8s-master default-mysql-pv-claim-pvc-a528b88f-23c7-11e9-9d07-000c291c25f3]$ ll
total 181172
-rw-r----- 1 polkitd ssh_keys 56 Jan 29 21:13 auto.cnf
-rw-r----- 1 polkitd ssh_keys 3090087 Jan 29 21:13 binlog.000001
-rw-r----- 1 polkitd ssh_keys 964626 Jan 29 21:28 binlog.000002
-rw-r----- 1 polkitd ssh_keys 32 Jan 29 21:13 binlog.index
-rw------- 1 polkitd ssh_keys 1676 Jan 29 21:13 ca-key.pem
-rw-r--r-- 1 polkitd ssh_keys 1112 Jan 29 21:13 ca.pem
-rw-r--r-- 1 polkitd ssh_keys 1112 Jan 29 21:13 client-cert.pem
-rw------- 1 polkitd ssh_keys 1676 Jan 29 21:13 client-key.pem
-rw-r----- 1 polkitd ssh_keys 5933 Jan 29 21:13 ib_buffer_pool
-rw-r----- 1 polkitd ssh_keys 12582912 Jan 29 21:28 ibdata1
-rw-r----- 1 polkitd ssh_keys 50331648 Jan 29 21:28 ib_logfile0
-rw-r----- 1 polkitd ssh_keys 50331648 Jan 29 21:13 ib_logfile1
-rw-r----- 1 polkitd ssh_keys 12582912 Jan 29 21:14 ibtmp1
drwxr-x--- 2 polkitd ssh_keys 187 Jan 29 21:13 #innodb_temp
drwxr-x--- 2 polkitd ssh_keys 143 Jan 29 21:13 mysql
-rw-r----- 1 polkitd ssh_keys 31457280 Jan 29 21:20 mysql.ibd
drwxr-x--- 2 polkitd ssh_keys 4096 Jan 29 21:13 performance_schema
-rw------- 1 polkitd ssh_keys 1676 Jan 29 21:13 private_key.pem
-rw-r--r-- 1 polkitd ssh_keys 452 Jan 29 21:13 public_key.pem
-rw-r--r-- 1 polkitd ssh_keys 1112 Jan 29 21:13 server-cert.pem
-rw------- 1 polkitd ssh_keys 1676 Jan 29 21:13 server-key.pem
drwxr-x--- 2 polkitd ssh_keys 28 Jan 29 21:13 sys
-rw-r----- 1 polkitd ssh_keys 12582912 Jan 29 21:28 undo_001
-rw-r----- 1 polkitd ssh_keys 11534336 Jan 29 21:28 undo_002
drwxr-x--- 2 polkitd ssh_keys 287 Jan 29 21:19 wordpress
执行pod删除操作，数据和配置不会丢失
[centos@k8s-master ~]$ kubectl delete pod wordpress-mysql-5fd57746c7-87f2m
Pv无法删除问题
PV处于Terminating并且无法删除：
[centos@k8s-master ~]$ kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
nfs-pv3 200M RWX Recycle Terminating kube-system/redis-data-redis-app-5 7h54m
nfs-pv4 200M RWX Recycle Terminating kube-system/redis-data-redis-app-2 7h54m
[centos@k8s-master ~]$ kubectl delete pv nfs-pv3
persistentvolume "nfs-pv3" deleted
^C
删除 kubernetes.io/pv-protection项 可强制删除处于Terminating状态的PV，更改后:wq保存即可。
[centos@k8s-master ~]$ kubectl edit pv nfs-pv3
......
finalizers:
- kubernetes.io/pv-protection #删除此行即可自动删除处于Terminating状态的PV
......
参考文档：
https://jimmysong.io/kubernetes-handbook/practice/using-nfs-for-persistent-storage.html
https://blog.csdn.net/aixiaoyang168/article/details/83988253
http://dockone.io/article/2598