本文介绍在kubernetes环境中部署mysql主从集群，数据持久化采用nfs。

一、环境介绍

Mysql版本：5.7

Mysql master节点：

主机名：vm1IP地址：192.168.115.5/24

Mysql slave节点：

主机名：vm2IP地址：192.168.115.6/24

NFS节点：

主机名：vm2IP地址：192.168.115.6/24共享目录：/home/mysql_master、/home/mysql_slave

二、准备mysql主从的镜像环境

dockerfile、docker-entrypoint.sh 文件下载地址如下由于我们要配置mysql主从，所以需要对dockerfile、docker-entrypoint.sh 文件做一点的修改，主要是在mysql主从配置部分。

准备master的镜像

将Dockerfile, docker-entrypoint.sh复制一份用于build master镜像文件。在Dockerfile中添加如下内容，将mysql master的server-id设置为1

RUN sed -i '/\[mysqld\]/a server-id=1\nlog-bin' /etc/mysql/mysql.conf.d/mysqld.cnf

在docker-entrypoint.sh中添加如下内容，创建一个复制用户并赋权限，刷新系统权限表

echo "CREATE USER '$MYSQL_REPLICATION_USER'@'%' IDENTIFIED BY '$MYSQL_REPLICATION_PASSWORD' ;" | "${mysql[@]}" echo "GRANT REPLICATION SLAVE ON *.* TO '$MYSQL_REPLICATION_USER'@'%' IDENTIFIED BY '$MYSQL_REPLICATION_PASSWORD' ;" | "${mysql[@]}" echo 'FLUSH PRIVILEGES ;' | "${mysql[@]}"

准备slave的镜像将Dockerfile, docker-entrypoint.sh复制一份用于build slave镜像文件。在Dockerfile中添加如下内容，将mysql slave的server-id设置为一个随机数

RUN RAND="$(date +%s | rev | cut -c 1-2)$(echo ${RANDOM})" && sed -i '/\[mysqld\]/a server-id='$RAND'\nlog-bin' /etc/mysql/mysql.conf.d/mysqld.cnf

在docker-entrypoint.sh中添加如下内容，配置连接master主机的host、user、password等参数，并启动复制进程。

echo "STOP SLAVE;" | "${mysql[@]}" echo "CHANGE MASTER TO master_host='$MYSQL_MASTER_SERVICE_HOST', master_user='$MYSQL_REPLICATION_USER', master_password='$MYSQL_REPLICATION_PASSWORD' ;" | "${mysql[@]}" echo "START SLAVE;" | "${mysql[@]}"

三、开始使用修改好的dockerfile创建mysql master和slave镜像

# cd /root/kubernetes/lnmp/mysql/Dockerfiles/Master# docker build -t registry.fjhb.cn/mysql-master:0.1 .# cd /root/kubernetes/lnmp/mysql/Dockerfiles/Slave# docker build -t registry.fjhb.cn/mysql-slave:0.1 .# docker push registry.fjhb.cn/mysql-master:0.1# docker push registry.fjhb.cn/mysql-slave:0.1

四、创建pv和pvc，用于mysql主从存储持久化数据在nfs服务器上把目录创建出来

# cd /home/# mkdir mysql_master mysql_slave

通过yaml文件创建出两组pv和pvc

# cd /root/kubernetes/lnmp/mysql/Storage# cat nfs-pv-master.yamlapiVersion: v1kind: PersistentVolumemetadata:  name: pv-nfs-mysql-masterspec:  capacity:    storage: 5Gi   accessModes:  - ReadWriteOnce  nfs:     path: /home/mysql_master    server: 192.168.115.6  persistentVolumeReclaimPolicy: Recycle # cat nfs-pvc-master.yamlkind: PersistentVolumeClaimapiVersion: v1metadata:  name: pv-nfs-mysql-masterspec:  accessModes:    - ReadWriteOnce  resources:    requests:      storage: 5Gi# cat nfs-pv-slave.yaml apiVersion: v1kind: PersistentVolumemetadata:  name: pv-nfs-mysql-slavespec:  capacity:    storage: 6Gi   accessModes:  - ReadWriteOnce  nfs:     path: /home/mysql_slave    server: 192.168.115.6  persistentVolumeReclaimPolicy: Recycle # cat nfs-pvc-slave.yaml kind: PersistentVolumeClaimapiVersion: v1metadata:  name: pv-nfs-mysql-slavespec:  accessModes:    - ReadWriteOnce  resources:    requests:      storage: 6Gi# kubectl create -f nfs-pv-master.yaml# kubectl create -f nfs-pvc-master.yaml# kubectl create -f nfs-pv-slave.yaml # kubectl create -f nfs-pvc-slave.yaml

五、根据yaml文件创建mysql master ReplicationController和services

# cat mysql-master-rc.yaml apiVersion: v1kind: ReplicationControllermetadata: name: mysql-master labels:  name: mysql-masterspec:  replicas: 1  selector:   name: mysql-master  template:   metadata:    labels:     name: mysql-master   spec:    containers:    - name: mysql-master      image: registry.fjhb.cn/mysql-master:0.1      volumeMounts:        - mountPath: /var/lib/mysql          name: mysql-master-data      ports:      - containerPort: 3306      env:      - name: MYSQL_ROOT_PASSWORD        value: "12345678"      - name: MYSQL_REPLICATION_USER        value: "repl"      - name: MYSQL_REPLICAITON_PASSWORD        value: "12345678"    volumes:     - name: mysql-master-data       persistentVolumeClaim:        claimName: pv-nfs-mysql-master# cat mysql-master-svc.yaml apiVersion: v1kind: Servicemetadata:  name: mysql-master  labels:   name: mysql-masterspec:  type: NodePort  ports:  - port: 3306    targetPort: 3306    name: http    nodePort: 30066  selector:    name: mysql-master# kubectl create -f mysql-master-rc.yaml # kubectl create -f mysql-master-svc.yaml

使用mysql客户端连接master测试六、根据yaml文件创建mysql slave ReplicationController和services

# cat mysql-slave-rc.yaml apiVersion: v1kind: ReplicationControllermetadata: name: mysql-slave labels:  name: mysql-slavespec:  replicas: 1  selector:   name: mysql-slave  template:   metadata:    labels:     name: mysql-slave   spec:    containers:    - name: mysql-slave      image: registry.fjhb.cn/mysql-slave:0.1      volumeMounts:        - mountPath: /var/lib/mysql          name: mysql-slave-data      ports:      - containerPort: 3306      env:      - name: MYSQL_ROOT_PASSWORD        value: "12345678"      - name: MYSQL_REPLICATION_USER        value: "repl"      - name: MYSQL_REPLICAITON_PASSWORD        value: "12345678"    volumes:     - name: mysql-slave-data       persistentVolumeClaim:        claimName: pv-nfs-mysql-slave# cat mysql-slave-svc.yaml apiVersion: v1kind: Servicemetadata:  name: mysql-slave  labels:   name: mysql-slavespec:  type: NodePort  ports:  - port: 3306    targetPort: 3306    name: http    nodePort: 30067  selector:    name: mysql-slave# kubectl create -f mysql-slave-rc.yaml # kubectl create -f mysql-slave-svc.yaml

七、测试与排错

通过mysql命令行连接slave查看复制的状态，发现状态是connecting使用slave 容器连接master,发现使用root账号可以正常连接，而使用repl账号无法正常连接，提示access deny修改master上的repl用户密码

mysql> alter user repl@'%' identified by "12345678";Query OK, 0 rows affected (0.00 sec)mysql> flush privileges;Query OK, 0 rows affected (0.00 sec)

完成上述修改后在slave上进行验证一下，repl账号可以正常连接

在slave上进行change master操作，因为创建镜像的时候并未配置GTID参数，所以这里不能使用MASTER_AUTO_POSITION=1参数，如果要开启，需要去修改Dockerfile，重新生成镜像。

mysql> stop slave;mysql> set global sql_slave_skip_counter=1;CHANGE MASTER TO \MASTER_HOST='mysql-master', \MASTER_USER='repl', \MASTER_PASSWORD='12345678';mysql> start slave;

参考文档：