本文介绍在Kubernetes集群中部署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：vm1

IP地址：192.168.115.5/24

Mysql slave节点：

主机名：vm2

IP地址：192.168.115.6/24

NFS节点：

主机名：vm2

IP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

https://github.com/docker-library/mysql/tree/master/5.7

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.yaml

apiVersion: v1

kind: PersistentVolume

metadata:

name: pv-nfs-mysql-master

spec:

capacity:

storage: 5Gi

accessModes:

- ReadWriteOnce

nfs:

path: /home/mysql_master

server: 192.168.115.6

persistentVolumeReclaimPolicy: Recycle

# cat nfs-pvc-master.yaml

kind: PersistentVolumeClaim

apiVersion: v1

metadata:

name: pv-nfs-mysql-master

spec:

accessModes:

- ReadWriteOnce

resources:

requests:

storage: 5Gi

# cat nfs-pv-slave.yaml

apiVersion: v1

kind: PersistentVolume

metadata:

name: pv-nfs-mysql-slave

spec:

capacity:

storage: 6Gi

accessModes:

- ReadWriteOnce

nfs:

path: /home/mysql_slave

server: 192.168.115.6

persistentVolumeReclaimPolicy: Recycle

# cat nfs-pvc-slave.yaml

kind: PersistentVolumeClaim

apiVersion: v1

metadata:

name: pv-nfs-mysql-slave

spec:

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: v1

kind: ReplicationController

metadata:

name: mysql-master

labels:

name: mysql-master

spec:

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: v1

kind: Service

metadata:

name: mysql-master

labels:

name: mysql-master

spec:

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: v1

kind: ReplicationController

metadata:

name: mysql-slave

labels:

name: mysql-slave

spec:

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: v1

kind: Service

metadata:

name: mysql-slave

labels:

name: mysql-slave

spec:

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;