kubernetes存储（四）——NFS Client Provisioner的配置应用+statefulset控制器+部署mysql主从复制集群

一、StorageClass简介
StorageClass提供了一种描述存储类（class）的方法，不同的class可能会映射到不同的服务质量等级和备份策略或其他策略等。

每个 StorageClass 都包含 provisioner、parameters 和 reclaim Policy 字段， 这些字段会在StorageClass需要动态分配 PersistentVolume 时会使用到。

StorageClass的属性
Provisioner（存储分配器）：用来决定使用哪个卷插件分配 PV，该字段必须指定。可以指定内部分配器，也可以指定外部分配器。外部分配器的代码地址为： kubernetes-incubator/external-storage，其中包括NFS和Ceph等。

Reclaim Policy（回收策略）：通过reclaimPolicy字段指定创建的Persistent Volume的回收策略，回收策略包括：Delete 或者 Retain，没有指定默认为Delete。

更多属性查看：https://kubernetes.io/zh/docs/concepts/storage/storage-classes/

二、NFS Client Provisioner的配置应用
NFS Client Provisioner是一个automatic provisioner，使用NFS作为存储，自动创建PV和对应的PVC，本身不提供NFS存储，需要外部先有一套NFS存储服务。

PV以 ${namespace}-${pvcName}-${pvName}`的命名格式提供（在NFS服务器上）
PV回收的时候以 archieved-${namespace}-${pvcName}-${pvName}的命名格式（在NFS服务器上）

nfs-client-provisioner源码地址：

https://github.com/kubernetes-incubator/external-storage/tree/master/nfs-client

2.1NFS动态分配PV示例：

首先修改外部主机server1的挂载目录

[root@server1 ~]# vim /etc/exports
 no_root_squash：增加权限，动态请求会修改目录权限
[root@server1 ~]# cat  /etc/exports   
/nfsdata          *(rw,sync,no_root_squash)
[root@server1 ~]# exportfs -rv  使之生效
exporting *:/nfsdata
[root@server1 ~]# showmount -e
Export list for server1:
/nfsdata *
[root@server1 ~]# cd /nfsdata
[root@server1 nfsdata]# ls
index.html  test.html
[root@server1 nfsdata]# rm -rf *
[root@server1 nfsdata]# ls

配置授权：

实验环境的纯净
[root@server2 ~]# kubectl get pod
No resources found in default namespace.
[root@server2 ~]# kubectl get cm
No resources found in default namespace.
[root@server2 ~]# kubectl get pv
No resources found in default namespace.
[root@server2 ~]# kubectl get pvc
No resources found in default namespace.
[root@server2 ~]# kubectl get all
NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
service/kubernetes   ClusterIP   10.96.0.1            443/TCP   3d10h

源代码获取


添加角色绑定的名称空间

[root@server2 ~]# cd vol/
[root@server2 vol]# mkdir nfs-client
[root@server2 vol]# cd nfs-client/
[root@server2 nfs-client]# 
[root@server2 nfs-client]# vim rbac.yml  
[root@server2 nfs-client]# cat rbac.yml
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

删除重复的选择器字段

[root@server2 nfs-client]# \vi deployment.yml
[root@server2 nfs-client]# cat deployment.yml
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: nfs-client-provisioner:latest 提前下载好镜像到仓库
          volumeMounts:
            - name: nfs-client-root
              mountPath: /persistentvolumes
          env:
            - name: PROVISIONER_NAME   分配器存储类的名称
              value: westos.org/nfs  定义分配器的名称
            - name: NFS_SERVER
              value: 172.25.254.31  定义nfs的主机
            - name: NFS_PATH
              value: /nfsdata  nfs的路径
      volumes:                外部的nfs卷      
        - name: nfs-client-root   指定卷名称
          nfs:
            server: 172.25.254.31   卷地址
            path: /nfsdata  卷名称

定义存储类

[root@server2 nfs-client]# vim  class.yml
[root@server2 nfs-client]# cat class.yml 
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: managed-nfs-storage
provisioner: westos.org/nfs   指定nfs分配器的名称
parameters:
  archiveOnDelete: "false"  存储回收策略，删除不打包，改为true删除会打包

创建pvc

[root@server2 nfs-client]# vim pvc.yml
[root@server2 nfs-client]# cat pvc.yml
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: test-claim
  annotations:
    volume.beta.kubernetes.io/storage-class: "managed-nfs-storage"
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 100Mi
[root@server2 nfs-client]# vim pod.yml   创建pod
[root@server2 nfs-client]# cat pod.yml
kind: Pod
apiVersion: v1
metadata:
  name: test-pod
spec:
  containers:
  - name: test-pod
    image: busybox:latest   确保镜像仓库有镜像
    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

[root@server2 nfs-client]# ls
claim.yml  class.yml  deployment.yml  pod.yml  rbac.yml

[root@server2 nfs-client]# kubectl get pvc
NAME   STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS          AGE
pvc1   Bound绑定    pvc-fd367a74-ef0b-4729-8f9e-0f57a10c949e   100Mi      RWX            managed-nfs-storage   26s

在外部存储查看
default（命名空间）-pvc1-pvc（pvc）-c3be4a0e-bc0d-4908-9286-6e19c18c7f63（pv名称）
SUCCESS：由pod创建

[root@server2 ~]# kubectl delete pod test-pod    删除pod 不会影响到pvc
pod "test-pod" deleted  
[root@server2 ~]# kubectl get storageclasses.storage.k8s.io  
NAME                  PROVISIONER      RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
managed-nfs-storage   westos.org/nfs   Delete          Immediate           false回收策略删除                  20h

[root@server2 ~]# kubectl delete pvc pvc1   删除pvc
persistentvolumeclaim "pvc1" deleted
[root@server1 default-pvc1-pvc-c3be4a0e-bc0d-4908-9286-6e19c18c7f63]# ls  外部挂载卷即/nfsdata下创建的文件会删除

存储回收策略，删除不打包，改为true删除会打包

[root@server2 nfs-client]# ls
class.yml  deployment.yml  pod.yml  pvc.yml  rbac.yml
[root@server2 nfs-client]# vim class.yml 
[root@server2 nfs-client]# cat  class.yml 
#apiVersion: storage.k8s.io/v1
#kind: StorageClass
#metadata:
#  name: managed-nfs-storage
#provisioner: westos.org/nfs
#parameters:
#  archiveOnDelete: "faset"

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: managed-nfs-storage
provisioner: westos.org/nfs
parameters:
  archiveOnDelete: "true"   改为true删除pvc后会定点打包

[root@server2 nfs-client]# kubectl patch storageclass managed-nfs-storage -p  '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'
storageclass.storage.k8s.io/managed-nfs-storage patched
[root@server2 nfs-client]# kubectl get storageclasses.storage.k8s.io 
NAME                            PROVISIONER      RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
managed-nfs-storage (default)   westos.org/nfs   Delete          Immediate           false                  53s

[root@server2 nfs-client]# kubectl apply -f pvc.yml   再次创建pvc
[root@server2 nfs-client]# kubectl apply -f class.yml
[root@server2 nfs-client]# kubectl delete -f pvc.yml   再次删除pvc则会打包
persistentvolumeclaim "pvc1" deleted

注意：打包会消耗nfs服务器的空间。

[root@server1 ~]# cd /nfsdata/
[root@server1 nfsdata]# ls
archived-default-pvc1-pvc-fd367a74-ef0b-4729-8f9e-0f57a10c949e    删除打包保存
default-pvc1-pvc-06ea0af3-c5fb-497d-8284-2ab6e2ccbfb4  新建

再次更改为：fase
2.2默认的 StorageClass 将被用于动态的为没有特定 storage class 需求的 PersistentVolumeClaims 配置存储：（只能有一个默认StorageClass）
如果没有默认StorageClass，PVC 也没有指定storageClassName 的值，那么意味着它只能够跟 storageClassName 也是“”的 PV 进行绑定。
此时不指定存储类也可以进行绑定

[root@server2 nfs-client]# kubectl get pv
No resources found in default namespace.
[root@server2 nfs-client]# kubectl get pvc
No resources found in default namespace.
[root@server2 nfs-client]# kubectl patch storageclass managed-nfs-storage -p  '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'
storageclass.storage.k8s.io/managed-nfs-storage patched
[root@server2 nfs-client]# kubectl get storageclasses.storage.k8s.io 
NAME                            PROVISIONER      RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
managed-nfs-storage (default)   westos.org/nfs   Delete          Immediate           false                  53s

[root@server2 nfs-client]# cat class.yml 
#apiVersion: storage.k8s.io/v1
#kind: StorageClass
#metadata:
#  name: managed-nfs-storage
#provisioner: westos.org/nfs
#parameters:
#  archiveOnDelete: "faset"   

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: managed-nfs-storage
provisioner: westos.org/nfs
parameters:
  archiveOnDelete: "false"  不打包
[root@server2 nfs-client]# cat pvc.yml 
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: pvc1
  #annotations:    不指定storageClassName 的值
  #  volume.beta.kubernetes.io/storage-class: "managed-nfs-storage"
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 100Mi

3.StatefulSe控制器
通过无头服务创建StatefulSe控制器维持Pod的拓扑状态
3.1创建service

[root@server2 ~]# cd nginx/
[root@server2 nginx]# ls
service.yml
[root@server2 nginx]# cat service.yml 
apiVersion: v1
kind: Service
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    name: web
  clusterIP: None
  selector:
    app: nginx
[root@server2 nginx]# kubectl apply -f service.yml 
service/nginx created
[root@server2 nginx]# kubectl get svc  Nginx无头服务none
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.96.0.1            443/TCP   7d1h
nginx        ClusterIP   None                 80/TCP    12s

3.2创建statefulset控制器

[root@server2 nginx]# vim statefulset.yml
[root@server2 nginx]# cat  statefulset.yml
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  serviceName: "nginx"
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx

[root@server2 nginx]# kubectl apply -f statefulset.yml 
statefulset.apps/web created
[root@server2 nginx]# kubectl get pod
NAME    READY   STATUS    RESTARTS   AGE
web-0   1/1     Running   0          9s
web-1   1/1     Running   0          8s

无头服务Nginx的域名解析

设置集群dns解析

[root@server2 nginx]# vim /etc/resolv.conf
[root@server2 nginx]# cat  /etc/resolv.conf
# Generated by NetworkManager
nameserver 114.114.114.114
nameserver 10.96.0.10

[root@server2 ~]# cd nginx/
[root@server2 nginx]# ls
service.yml  statefulset.yml
[root@server2 nginx]# vim statefulset.yml 
[root@server2 nginx]# cat statefulset.yml 
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  serviceName: "nginx"
  replicas: 4
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx

[root@server2 nginx]# kubectl apply -f statefulset.yml 
statefulset.apps/web configured
[root@server2 nginx]# kubectl get svc nginx 
NAME    TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
nginx   ClusterIP   None                 80/TCP    18m
[root@server2 nginx]# kubectl get pod
NAME    READY   STATUS    RESTARTS   AGE
web-0   1/1     Running   0          16m
web-1   1/1     Running   0          16m
web-2   1/1     Running   0          15s
web-3   1/1     Running   0          13s

[root@server2 nginx]# dig nginx.default.svc.cluster.local

; <<>> DiG 9.9.4-RedHat-9.9.4-72.el7 <<>> nginx.default.svc.cluster.local
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 50140
;; flags: qr aa rd; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;nginx.default.svc.cluster.local. IN	A

;; ANSWER SECTION:
nginx.default.svc.cluster.local. 30 IN	A	10.244.1.11
nginx.default.svc.cluster.local. 30 IN	A	10.244.2.15
nginx.default.svc.cluster.local. 30 IN	A	10.244.2.16
nginx.default.svc.cluster.local. 30 IN	A	10.244.1.12

;; Query time: 1 msec
;; SERVER: 10.96.0.10#53(10.96.0.10)
;; WHEN: Wed Jul 15 23:43:59 CST 2020
;; MSG SIZE  rcvd: 248

[root@server2 nginx]# kubectl get pod -o wide   依次创建pod
NAME    READY   STATUS    RESTARTS   AGE   IP            NODE      NOMINATED NODE   READINESS GATES
web-0   1/1     Running   0          30m   10.244.2.15   server3              
web-1   1/1     Running   0          30m   10.244.1.11   server4              
web-2   1/1     Running   0          13m   10.244.2.16   server3              
web-3   1/1     Running   0          13m   10.244.1.12   server4              

root@server2 nginx]# dig web-2.nginx.default.svc.cluster.local

3.3使用statefulset控制器缩减pod（递归缩减）
StatefulSet将应用状态抽象成了两种情况：

拓扑状态：应用实例必须按照某种顺序启动。新创建的Pod必须和原来Pod的网络标识一样
存储状态：应用的多个实例分别绑定了不同存储数据。

StatefulSet给所有的Pod进行了编号，编号规则是：$(statefulset名称)-$(序号)，从0开始。

Pod被删除后重建，重建Pod的网络标识也不会改变,Pod的拓扑状态按照Pod的“名字+编号”的方式固定下来,并且为每个Pod提供了一个固定且唯一的访问入口,即Pod对应的DNS记录。
首先,想要弹缩的StatefulSet. 需先清楚是否能弹缩该应用.

kubectl get statefulsets 

改变StatefulSet副本数量: kubectl scale statefulsets --replicas=“数量”
• 如果StatefulSet开始由 kubectl apply 或 kubectl create --save-config 创建,更新StatefulSet manifests中的 .spec.replicas, 然后执行命令 kubectl apply: kubectl apply -f
也可以通过命令 kubectl edit 编辑该字段: kubectl edit statefulsets
使用 kubectl patch: kubectl patch statefulsets -p ‘{“spec”:{“replicas”:}}’

[root@server2 nginx]# vim statefulset.yml 
[root@server2 nginx]# cat  statefulset.yml 
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  serviceName: "nginx"
  replicas: 0
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx

[root@server2 nginx]# kubectl apply -f statefulset.yml 
statefulset.apps/web configured

pod回收完成再次无法解析域名

再次创建，依次创建pod

3.3 StatefulSet+存储
PV和PVC的设计，使得StatefulSet对存储状态的管理成为了可能:
Pod的创建也是严格按照编号顺序进行的。比如在web-0进入到running状态，并且Conditions为 Ready之前，web-1一直会处于pending状态。

[root@server2 nginx]# vim statefulset.yml 
[root@server2 nginx]# cat statefulset.yml 
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  serviceName: "nginx"
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        volumeMounts:
          - name: www
            mountPath: /usr/share/nginx/html
  volumeClaimTemplates:
    - metadata:
        name: www
      spec:
        storageClassName: managed-nfs-storage
        accessModes:
        - ReadWriteOnce
        resources:
          requests:
            storage: 1Gi

[root@server2 nginx]# kubectl apply -f statefulset.yml 
statefulset.apps/web created

[root@server2 nginx]# kubectl get pvc
NAME        STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS          AGE
www-web-0   Bound    pvc-e75c3cfd-7e89-407d-bf4d-e3dd2a8d10f4   1Gi        RWO            managed-nfs-storage   8m11s
www-web-1   Bound    pvc-8ea48b18-b676-42f4-b802-485ab4502bb9   1Gi        RWO            managed-nfs-storage   8m7s
www-web-2   Bound    pvc-9d5a3796-b533-4e84-b5b4-02d4f82a7564   1Gi        RWO            managed-nfs-storage   8m3s

StatefulSet还会为每一个Pod分配并创建一个同样编号的PVC。这样，kubernetes就可以通过 Persistent Volume机制为这个PVC绑定对应的PV，从而保证每一个Pod都拥有一个独立的 Volume。

[root@server2 nginx]# kubectl get pod
NAME                                     READY   STATUS    RESTARTS   AGE
nfs-client-provisioner-6f4658b4d-rz2rd   1/1     Running   0          2m1s
web-0                                    1/1     Running   0          56s
web-1                                    1/1     Running   0          52s
web-2                                    1/1     Running   0          48s

设置负载均衡：在外出挂载存储点编辑挂载卷

如下实现负载均衡




再次拉伸到之前


四、使用statefullset部署mysql主从集群:
参考网址：
https://kubernetes.io/zh/docs/tasks/run-application/run-replicated-stateful-application/

3.1创建configmap配置文件
ConfigMap 提供 my.cnf 覆盖，使之可以独立控制 MySQL 的主服务器和从服务器的配置。

[root@server2 ~]# mkdir mysql
[root@server2 ~]# cd mysql/
[root@server2 mysql]# \vi cm.yml
[root@server2 mysql]# vim  cm.yml
[root@server2 mysql]# cat   cm.yml
apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql
  labels:
    app: mysql
data:
  master.cnf: |
    # Apply this config only on the master.
    [mysqld]
    log-bin
  slave.cnf: |
    # Apply this config only on slaves.
    [mysqld]
    super-read-only

3.2创建service
Headless Service 给 StatefulSet 控制器为集合中每个 Pod 创建的 DNS 条目提供了一个宿主。因为 Headless Service 名为 mysql，所以可以通过在同一 Kubernetes 集群和 namespace 中的任何其他 Pod 内解析 .mysql 来访问 Pod。

客户端 Service 称为 mysql-read，是一种常规 Service，具有其自己的群集 IP，该群集 IP 在报告为就绪的所有MySQL Pod 中分配连接。可能端点的集合包括 MySQL 主节点和所有从节点。

请注意，只有读取查询才能使用负载平衡的客户端 Service。因为只有一个 MySQL 主服务器，所以客户端应直接连接到 MySQL 主服务器 Pod (通过其在 Headless Service 中的 DNS 条目)以执行写入操作

[root@server2 mysql]# \vi service.yml
[root@server2 mysql]# vim  service.yml
[root@server2 mysql]# cat   service.yml
# Headless service for stable DNS entries of StatefulSet members.
apiVersion: v1
kind: Service
metadata:
  name: mysql
  labels:
    app: mysql
spec:
  ports:
  - name: mysql
    port: 3306
  clusterIP: None
  selector:
    app: mysql
---
# Client service for connecting to any MySQL instance for reads.
# For writes, you must instead connect to the master: mysql-0.mysql.
apiVersion: v1
kind: Service
metadata:
  name: mysql-read
  labels:
    app: mysql
spec:
  ports:
  - name: mysql
    port: 3306
  selector:
    app: mysql

[root@server2 mysql]# kubectl apply -f service.yml 
service/mysql created
service/mysql-read created
[root@server2 mysql]# kubectl get svc
NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)    AGE
kubernetes   ClusterIP   10.96.0.1               443/TCP    7d3h
mysql        ClusterIP   None                    3306/TCP   18s
mysql-read   ClusterIP   10.101.21.238           3306/TCP   18s

创建StatefulSet

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: mysql
spec:
  selector:
    matchLabels:
      app: mysql
  serviceName: mysql
  replicas: 3
  template:
    metadata:
      labels:
        app: mysql
    spec:
      initContainers:
      - name: init-mysql
        image: mysql:5.7   镜像仓库必须有
        command:
        - bash
        - "-c"
        - |
          set -ex
          # Generate mysql server-id from pod ordinal index.
          [[ `hostname` =~ -([0-9]+)$ ]] || exit 1
          ordinal=${BASH_REMATCH[1]}
          echo [mysqld] > /mnt/conf.d/server-id.cnf
          # Add an offset to avoid reserved server-id=0 value.
          echo server-id=$((100 + $ordinal)) >> /mnt/conf.d/server-id.cnf
          # Copy appropriate conf.d files from config-map to emptyDir.
          if [[ $ordinal -eq 0 ]]; then
            cp /mnt/config-map/master.cnf /mnt/conf.d/
          else
            cp /mnt/config-map/slave.cnf /mnt/conf.d/
          fi
        volumeMounts:
        - name: conf
          mountPath: /mnt/conf.d
        - name: config-map
          mountPath: /mnt/config-map
      - name: clone-mysql
        image: xtrabackup:1.0
        command:
        - bash
        - "-c"
        - |
          set -ex
          # Skip the clone if data already exists.
          [[ -d /var/lib/mysql/mysql ]] && exit 0
          # Skip the clone on master (ordinal index 0).
          [[ `hostname` =~ -([0-9]+)$ ]] || exit 1
          ordinal=${BASH_REMATCH[1]}
          [[ $ordinal -eq 0 ]] && exit 0
          # Clone data from previous peer.
          ncat --recv-only mysql-$(($ordinal-1)).mysql 3307 | xbstream -x -C /var/lib/mysql
          # Prepare the backup.
          xtrabackup --prepare --target-dir=/var/lib/mysql
        volumeMounts:
        - name: data
          mountPath: /var/lib/mysql
          subPath: mysql
        - name: conf
          mountPath: /etc/mysql/conf.d
      containers:
      - name: mysql
        image: mysql:5.7
        env:
        - name: MYSQL_ALLOW_EMPTY_PASSWORD
          value: "1"
        ports:
        - name: mysql
          containerPort: 3306
        volumeMounts:
        - name: data
          mountPath: /var/lib/mysql
          subPath: mysql
        - name: conf
          mountPath: /etc/mysql/conf.d
        resources:
          requests:
            cpu: 500m
            memory: 1Gi
        livenessProbe:
          exec:
            command: ["mysqladmin", "ping"]
          initialDelaySeconds: 30
          periodSeconds: 10
          timeoutSeconds: 5
        readinessProbe:
          exec:
            # Check we can execute queries over TCP (skip-networking is off).
            command: ["mysql", "-h", "127.0.0.1", "-e", "SELECT 1"]
          initialDelaySeconds: 5
          periodSeconds: 2
          timeoutSeconds: 1
      - name: xtrabackup
        image: xtrabackup:1.0
        ports:
        - name: xtrabackup：   镜像仓库必须有          containerPort: 3307
        command:
        - bash
        - "-c"
        - |
          set -ex
          cd /var/lib/mysql

          # Determine binlog position of cloned data, if any.
          if [[ -f xtrabackup_slave_info && "x$()" != "x" ]]; then
            # XtraBackup already generated a partial "CHANGE MASTER TO" query
            # because we're cloning from an existing slave. (Need to remove the tailing semicolon!)
            cat xtrabackup_slave_info | sed -E 's/;$//g' > change_master_to.sql.in
            # Ignore xtrabackup_binlog_info in this case (it's useless).
            rm -f xtrabackup_slave_info xtrabackup_binlog_info
          elif [[ -f xtrabackup_binlog_info ]]; then
            # We're cloning directly from master. Parse binlog position.
            [[ `cat xtrabackup_binlog_info` =~ ^(.*?)[[:space:]]+(.*?)$ ]] || exit 1
            rm -f xtrabackup_binlog_info xtrabackup_slave_info
            echo "CHANGE MASTER TO MASTER_LOG_FILE='${BASH_REMATCH[1]}',\
                  MASTER_LOG_POS=${BASH_REMATCH[2]}" > change_master_to.sql.in
          fi

          # Check if we need to complete a clone by starting replication.
          if [[ -f change_master_to.sql.in ]]; then
            echo "Waiting for mysqld to be ready (accepting connections)"
            until mysql -h 127.0.0.1 -e "SELECT 1"; do sleep 1; done

            echo "Initializing replication from clone position"
            mysql -h 127.0.0.1 \
                  -e "$(.sql.in), \
                          MASTER_HOST='mysql-0.mysql', \
                          MASTER_USER='root', \
                          MASTER_PASSWORD='', \
                          MASTER_CONNECT_RETRY=10; \
                        START SLAVE;" || exit 1
            # In case of container restart, attempt this at-most-once.
            mv change_master_to.sql.in change_master_to.sql.orig
          fi

          # Start a server to send backups when requested by peers.
          exec ncat --listen --keep-open --send-only --max-conns=1 3307 -c \
            "xtrabackup --backup --slave-info --stream=xbstream --host=127.0.0.1 --user=root"
        volumeMounts:
        - name: data
          mountPath: /var/lib/mysql
          subPath: mysql
        - name: conf
          mountPath: /etc/mysql/conf.d
        resources:
          requests:
            cpu: 100m
            memory: 100Mi
      volumes:
      - name: conf
        emptyDir: {}
      - name: config-map
        configMap:
          name: mysql
  volumeClaimTemplates:
  - metadata:
      name: data
    spec:
      accessModes: ["ReadWriteOnce"]
      resources:
        requests:
          storage: 10Gi

[root@server2 nfs-client]# kubectl get storageclasses.storage.k8s.io 
NAME                            PROVISIONER      RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
managed-nfs-storage (default)   westos.org/nfs   Delete          Immediate           false                  2m11s

[root@server1 ~]# docker push reg.westos.org/library/xtrabackup:1.0 
The push refers to repository [reg.westos.org/library/xtrabackup]
f85c58969eb0: Pushed 
82d548d175dd: Pushed 
fe4c16cbf7a4: Pushed 
1.0: digest: sha256:39f106eb400e18dcb4bded651a7ab308b39c305578ce228ae35f3c76bc715510 size: 949

docker load导入镜像报错：open /var/lib/docker/tmp/docker-import-970689518/bin/json: no such file or directory
今天将之前打包好的mysql5.7的tar包通过docker load命令导入到Docker环境中却报出了如下错误：
[root@server1 ~]# docker load -i mysql-5.7.17-1.el6.x86_64.rpm-bundle.tar
open /var/lib/docker/tmp/docker-import-578020953/repositories: no such file or directory

错误反应的意思是mysql5.7.19这个tar包缺少docker所需要的一些json文件，它只包含了layer.tar这个文件夹，缺少json这个文件夹，因此mysql5.7.19.tar只是一个tar包，并不能直接用docker load导入。

解决办法如下

[root@server1 ~]#  cat mysql-5.7.17-1.el6.x86_64.rpm-bundle.tar | docker import - mysql-5.7
sha256:475b8072b16469a4a2020b7b7b5ac4681a2ee5a2d6960167cf4f92a50fbc2cef

[root@server1 ~]# docker images | grep mysql-5.7
mysql-5.7                                         latest                           475b8072b164        About a minute ago   470MB

未完成