如何基于docker搭建mysql8.0主从复制从而实现读写分离
前言
1、 docker的安装与mysql8.0镜像的打包这里不做详细介绍。以后有时间再出详细教程。安装好docker运行环境拉去mysql8镜像,我使用的是自己源码编译的mysql8.0。docker-hub地址如下
docker pull gongxulei/centos-lnmp:mysql8
2、主从复制原理
Master 主库在事务提交时,会把数据变更作为时间 Events 记录在二进制日志文件 Binlog 中。主库推送二进制日志文件 Binlog 中的日志事件到从库的中继日志 Relay Log 。slave重做中继日志中的事件,将改变反映它自己的数据。mysql的主从复制是基于bin-log实现的,因此需要开启bin-log配置,另外mysql8.0默认是开启bin-log的。
如下图所示mysql的主从复制主要分三步实现:
知道了原理我们下面开始搭建
搭建mysql8.0主从复制
1、master搭建
修改配置并启动一个msql的容器(1)f 配置如下
# bin-log二进制日志设置log-bin=/usr/local/mysql/log/mysqlbin/mysql-bin# logging format: mixed|statement|rowbinlog_format=statement# 主从配置master# required unique id between 1 and 2^32 - 1 defaults to 1 if master-host is not setserver-id = 1#是否只读,1 代表只读, 0 代表读写read-only=0#忽略的数据, 指不需要同步的数据库binlog-ignore-db=mysql#指定同步的数据库#binlog-do-db=db01
(2) 启动容器
我这里使用的 -v 来挂载了mysql 的data数据目录、etc配置目录、log日志目录
并映射的容器的3306端口到宿主机3306端口
# docker-mysql-masterdocker run -d -it --privileged=true -p 3306:3306 -v /Users/gongxulei/docker/mysql/master/data:/usr/local/mysql/data -v /Users/gongxulei/docker/mysql/master/etc:/usr/local/mysql/etc -v /Users/gongxulei/docker/mysql/master/log:/usr/local/mysql/log --name my-app-mysql8-master 449f953ecd8b
(3) 初始化mysql并启动mysql
我这里初始化指定了mysql的 --log-bin 文件路径,是因为我没有采用默认的目录(data目录)
如果指定会无法初始化。具体原因见我的之前的一篇文章
# 初始化data目录/usr/local/mysql/bin/mysqld --initialize-insecure --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data --log-bin=/usr/local/mysql/log/mysqlbin/mysql-bin --user=mysql# 以守护进程方式启动mysql/usr/local/mysql/bin/mysqld_safe --user=mysql &
(4) 设置mysql主从复制账户
# 登录mysql/usr/local/mysql/bin/mysql -uroot -p# 设置master的root账户密码 并且允许外部连接mysqlalter mysql.user set host='%' where user='root' and host='localhost';alter user 'root'@'%' identified by 'root123456';# 设置当前master授予slave的账户(用于从库复制)# 注意:这里的ip为slave的ip地址。意思是允许此ip通过账户slave1来访问master数据库create user 'slave1'@'172.17.0.5' identified by 'slave1123456';# 授予slave权限并刷新权限grant replication slave on *.* to 'slave1'@'172.17.0.5';flush privileges;
此时可以使用 show master status命令查看master数据库状态
# 后面设置slave会用到下面的字段mysql> show master status;+------------------+----------+--------------+------------------+-------------------+| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |+------------------+----------+--------------+------------------+-------------------+| mysql-bin.000006 |869 | | mysql | |+------------------+----------+--------------+------------------+-------------------+字段含义:File : 从哪个日志文件开始推送日志文件 Position : 从哪个位置开始推送日志Binlog_Ignore_DB : 指定不需要同步的数据库
2、slave搭建
(1)f 配置如下
# bin-log二进制日志设置log-bin=/usr/local/mysql/log/mysqlbin/mysql-bin# logging format: mixed|statement|rowbinlog_format=statement# 主从配置slave# required unique id between 1 and 2^32 - 1 defaults to 1 if master-host is not setserver-id = 2
(2) 启动容器
我这里使用的 -v 来挂载了mysql 的data数据目录、etc配置目录、log日志目录
并映射的容器的3306端口到宿主机3307端口
# docker-mysql-slavedocker run -d -it --privileged=true -p 3307:3306 -v /Users/gongxulei/docker/mysql/slave1/data:/usr/local/mysql/data -v /Users/gongxulei/docker/mysql/slave1/etc:/usr/local/mysql/etc -v /Users/gongxulei/docker/mysql/slave1/log:/usr/local/mysql/log --name my-app-mysql8-slave1 449f953ecd8b
(3) 初始化mysql并启动mysql
初始化与上面master一致
(4) 设置slave账户并开启salve复制
下面用到的master_host地址为master服务器的IP地址。
master_user,master_password 是之前在master服务器设置的用于主从复制的账户密码
master_log_file,master_log_pos 是master服务器中执行show master status的信息
# 设置密码: 参考上面master的root账户设置# 设置slave账户change master to master_host= '172.17.0.4', master_user='slave1', master_password='slave1123456', master_log_file='mysql-bin.000006', master_log_pos=869;# 开启slave模式start slave;
此时可通过 show slave status命令查看slave是否设置成功
Slave_IO_Running: Yes Slave_SQL_Running: Yes 说明slave设置成功
mysql> show slave status\G;*************************** 1. row ***************************Slave_IO_State: Waiting for master to send eventMaster_Host: 172.17.0.4Master_User: slave1Master_Port: 3306Connect_Retry: 60Master_Log_File: mysql-bin.000006Read_Master_Log_Pos: 1713Relay_Log_File: 4a63c19c8af1-relay-bin.000002Relay_Log_Pos: 1168Relay_Master_Log_File: mysql-bin.000006Slave_IO_Running: YesSlave_SQL_Running: YesReplicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0Last_Error: Skip_Counter: 0Exec_Master_Log_Pos: 1713Relay_Log_Space: 1384Until_Condition: NoneUntil_Log_File: Until_Log_Pos: 0Master_SSL_Allowed: NoMaster_SSL_CA_File: Master_SSL_CA_Path: Master_SSL_Cert: Master_SSL_Cipher: Master_SSL_Key: Seconds_Behind_Master: 0Master_SSL_Verify_Server_Cert: NoLast_IO_Errno: 0Last_IO_Error: Last_SQL_Errno: 0Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 1Master_UUID: 7f06a326-b845-11ea-85b9-0242ac110002Master_Info_File: mysql.slave_master_infoSQL_Delay: 0SQL_Remaining_Delay: NULLSlave_SQL_Running_State: Slave has read all relay log; waiting for more updatesMaster_Retry_Count: 86400Master_Bind: Last_IO_Error_Timestamp: Last_SQL_Error_Timestamp: Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: Executed_Gtid_Set: Auto_Position: 0Replicate_Rewrite_DB: Channel_Name: Master_TLS_Version: Master_public_key_path: Get_master_public_key: 0Network_Namespace: 1 row in set (0.00 sec)ERROR: No query specified
3、测试主从是否成功
在mysql的master服务器中创建数据库并查看是否同步到slave中
# 在master中创建数据库并新增一张测试表CREATE DATABASE `master_test`DROP TABLE IF EXISTS `test1`;CREATE TABLE `test1` (`id` int unsigned NOT NULL AUTO_INCREMENT,`name` varchar(255) COLLATE utf8mb4_general_ci DEFAULT NULL,PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci COMMENT='这是一张测试master-slave的表';
如图上图所示,在slave服务器也有了对应的库跟表,那么恭喜你搭建成功了