多主一从,也称为多源复制,数据流向:
- 主库 1
-> 从库 s - 主库 2 -> 从库 s
- 主库 n
-> 从库 s
应用场景
- 数据汇总,可将多个主数据库同步汇总到一个从数据库中,方便数据统计分析。
- 读写分离,从库只用于查询,提高数据库整体性能。
部署环境
注:使用 docker 部署 mysql 实例,方便快速搭建演示环境。但本文重点是讲解主从配置,因此简略描述 docker 环境构建 mysql
容器实例。
- 数据库:MySQL
5.7.x (相比 5.5,5.6 而言,5.7 同步性能更好,支持多源复制,可实现多主一从,主从库版本应保证一致) - 操作系统:CentOS 7.x
- 容器:Docker 17.09.0-ce
- 镜像:mysql:5.7
- 主库 300:IP=192.168.10.212;
PORT=4300; server-id=300; database=test3; table=user - 主库 400:IP=192.168.10.212;
PORT=4400; server-id=400; database=test4; table=user - 主库 500:IP=192.168.10.212;
PORT=4500; server-id=500; database=test5; table=user - 从库
10345:IP=192.168.10.212; PORT=4345; server-id=10345; database=test3,test4,test5;
table=user
配置约束
- 主从库必须保证网络畅通可访问
- 主库必须开启 binlog 日志
- 主从库的
server-id 必须不同
事前准备
- 关闭
selinux
setenforce 0
vim /etc/sysconfig/selinux
SELINUX=disabled
# 若不关闭,使用docker启动mysql5.7镜像容器时启动不起来,查看日志会有如下错误显示:
ERROR: mysqld failed while attempting to check config
command was: "mysqld --verbose --help"
mysqld: Can't read dir of '/etc/mysql/conf.d/' (Errcode: 13 - Permission denied)
mysqld: [ERROR] Fatal error in defaults handling. Program aborted!
ERROR: mysqld failed while attempting to check config
command was: "mysqld --verbose --help"
mysqld: Can't read dir of '/etc/mysql/conf.d/' (Errcode: 13 - Permission denied)
mysqld: [ERROR] Fatal error in defaults handling. Program aborted!
- 安装并启动
docker
yum install epel-release
yum -y install docker
systemctl start docker.service
- 创建目录
mkdir -p /datavol/mysql-300/{mysql,conf}
mkdir -p /datavol/mysql-400/{mysql,conf}
mkdir -p /datavol/mysql-500/{mysql,conf}
mkdir -p /datavol/mysql-10345/{mysql,conf}
【主库 300】操作及配置
配置
my.cnf
把该文件放到主库所在配置文件路径下:/datavol/mysql-300/conf
[client]
port = 3306
default-character-set = utf8mb4
[mysql]
port = 3306
default-character-set = utf8mb4
[mysqld]
##########################
# summary
##########################
#bind-address = 0.0.0.0
#port = 3306
#datadir=/datavol/mysql/data #数据存储目录
##########################
# log bin
##########################
server-id = 300 #必须唯一
log_bin = mysql-bin #开启及设置二进制日志文件名称
binlog_format = MIXED
sync_binlog = 1
expire_logs_days =7 #二进制日志自动删除/过期的天数。默认值为0,表示不自动删除。
#binlog_cache_size = 128m
#max_binlog_cache_size = 512m
#max_binlog_size = 256M
binlog-do-db = test3 #要同步的数据库
binlog-ignore-db = mysql #不需要同步的数据库
binlog_ignore_db = information_schema
binlog_ignore_db = performation_schema
binlog_ignore_db = sys
##########################
# character set
##########################
character-set-server = utf8mb4
collation-server = utf8mb4_unicode_ci
安装启动
[root@localhost ~]# docker run -d -p 4300:3306 --name=mysql-300 -v /datavol/mysql-300/conf:/etc/mysql/conf.d -v /datavol/mysql-300/mysql:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=123456 mysql:5.7
5691bac538e646db00273e3cad5b350dbe6cce0bd176346b7eefd9a6f9e3a9ad
[root@localhost ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
5691bac538e6 mysql:5.7 "docker-entrypoint..." 44 seconds ago Up 43 seconds 33060/tcp, 0.0.0.0:4300->3306/tcp mysql-300
[root@localhost ~]# docker exec -it mysql-300 /bin/bash
root@5691bac538e6:/# mysql -u root -p
Enter password:
注:若不熟悉
docker,可使用传统方式安装 mysql,效果相同。
创建授权用户
连接
mysql 主数据库,键入命令 mysql -u root -p,输入密码后登录数据库。创建用户用于从库同步复制,授予复制、同步访问的权限
mysql> CREATE USER 'slave'@'%' IDENTIFIED BY '123456';
Query OK, 0 rows affected (0.00 sec)
mysql> grant replication slave on *.* to 'slave'@'%' identified by '123456';
Query OK, 0 rows affected (0.00 sec)
log_bin
是否开启
mysql> show variables like 'log_bin';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_bin | ON |
+---------------+-------+
1 row in set
查看
master 状态
mysql> show master status /G
*************************** 1. row ***************************
File: mysql-bin.000003
Position: 438
Binlog_Do_DB: test3
Binlog_Ignore_DB: mysql,information_schema,performation_schema,sys
【主库 400】配置及操作
配置
my.cnf
把该文件放到主库所在配置文件路径下:/datavol/mysql-400/conf
[client]
port = 3306
default-character-set = utf8mb4
[mysql]
port = 3306
default-character-set = utf8mb4
[mysqld]
##########################
# summary
##########################
#bind-address = 0.0.0.0
#port = 3306
#datadir=/datavol/mysql/data #数据存储目录
##########################
# log bin
##########################
server-id = 400 #必须唯一
log_bin = mysql-bin #开启及设置二进制日志文件名称
binlog_format = MIXED
sync_binlog = 1
expire_logs_days =7 #二进制日志自动删除/过期的天数。默认值为0,表示不自动删除。
#binlog_cache_size = 128m
#max_binlog_cache_size = 512m
#max_binlog_size = 256M
binlog-do-db = test4 #要同步的数据库
binlog-ignore-db = mysql #不需要同步的数据库
binlog_ignore_db = information_schema
binlog_ignore_db = performation_schema
binlog_ignore_db = sys
##########################
# character set
##########################
character-set-server = utf8mb4
collation-server = utf8mb4_unicode_ci
安装启动
[root@localhost ~]# docker run -d -p 4400:3306 --name=mysql-400 -v /datavol/mysql-400/conf:/etc/mysql/conf.d -v /datavol/mysql-400/mysql:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=123456 mysql:5.7
19e93b6d93ca4e6ca0d540e3f6c831b835cdbb35362733867c3977aee4d33bf7
[root@localhost ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
19e93b6d93ca mysql:5.7 "docker-entrypoint..." 4 seconds ago Up 3 seconds 33060/tcp, 0.0.0.0:4400->3306/tcp mysql-400
[root@localhost ~]# docker exec -it mysql-400 /bin/bash
root@19e93b6d93ca:/# mysql -u root -p
Enter password:
创建授权用户
创建用户用于从库同步复制,授予复制、同步访问的权限
mysql> CREATE USER 'slave'@'%' IDENTIFIED BY '123456';
Query OK, 0 rows affected (0.00 sec)
mysql> grant replication slave on *.* to 'slave'@'%' identified by '123456';
Query OK, 0 rows affected (0.00 sec)
log_bin
是否开启
mysql> show variables like 'log_bin';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_bin | ON |
+---------------+-------+
1 row in set
查看
master 状态
mysql> show master status /G;
*************************** 1. row ***************************
File: mysql-bin.000003
Position: 438
Binlog_Do_DB: test4
Binlog_Ignore_DB: mysql,information_schema,performation_schema,sys
【主库 500】配置及操作
配置
my.cnf
把该文件放到主库所在配置文件路径下:/datavol/mysql-500/conf
[client]
port = 3306
default-character-set = utf8mb4
[mysql]
port = 3306
default-character-set = utf8mb4
[mysqld]
##########################
# summary
##########################
#bind-address = 0.0.0.0
#port = 3306
#datadir=/datavol/mysql/data #数据存储目录
##########################
# log bin
##########################
server-id = 500 #必须唯一
log_bin = mysql-bin #开启及设置二进制日志文件名称
binlog_format = MIXED
sync_binlog = 1
expire_logs_days =7 #二进制日志自动删除/过期的天数。默认值为0,表示不自动删除。
#binlog_cache_size = 128m
#max_binlog_cache_size = 512m
#max_binlog_size = 256M
binlog-do-db = test5 #要同步的数据库
binlog-ignore-db = mysql #不需要同步的数据库
binlog_ignore_db = information_schema
binlog_ignore_db = performation_schema
binlog_ignore_db = sys
##########################
# character set
##########################
character-set-server = utf8mb4
collation-server = utf8mb4_unicode_ci
安装启动
[root@localhost ~]# docker run -d -p 4500:3306 --name=mysql-500 -v /datavol/mysql-500/conf:/etc/mysql/conf.d -v /datavol/mysql-500/mysql:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=123456 mysql:5.7
19e93b6d93ca4e6ca0d540e3f6c831b835cdbb35362733867c3977aee4d33bf7
[root@localhost ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
19e93b6d93ca mysql:5.7 "docker-entrypoint..." 4 seconds ago Up 3 seconds 33060/tcp, 0.0.0.0:4500->3306/tcp mysql-500
[root@localhost ~]# docker exec -it mysql-500 /bin/bash
root@19e93b6d93ca:/# mysql -u root -p
Enter password:
创建授权用户
创建用户用于从库同步复制,授予复制、同步访问的权限
mysql> CREATE USER 'slave'@'%' IDENTIFIED BY '123456';
Query OK, 0 rows affected (0.00 sec)
mysql> grant replication slave on *.* to 'slave'@'%' identified by '123456';
Query OK, 0 rows affected (0.00 sec)
log_bin
是否开启
mysql> show variables like 'log_bin';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_bin | ON |
+---------------+-------+
1 row in set
查看
master 状态
mysql> show master status /G
*************************** 1. row ***************************
File: mysql-bin.000003
Position: 438
Binlog_Do_DB: test5
Binlog_Ignore_DB: mysql,information_schema,performation_schema,sys
【从库 10345】配置及操作
配置
my.cnf
把该文件放到主库所在配置文件路径下:/datavol/mysql-10345/conf
[client]
port = 3306
default-character-set = utf8mb4
[mysql]
port = 3306
default-character-set = utf8mb4
[mysqld]
##########################
# summary
##########################
#bind-address = 0.0.0.0
#port = 3306
#datadir=/datavol/mysql/data #数据存储目录
##########################
# log bin
##########################
server-id = 10345
master_info_repository = table
relay_log_info_repository = table
##########################
# character set
##########################
character-set-server = utf8mb4
collation-server = utf8mb4_unicode_ci
安装启动
[root@localhost ~]# docker run -d -p 4345:3306 --name=mysql-10345 -v /datavol/mysql-10345/conf:/etc/mysql/conf.d -v /datavol/mysql-10345/mysql:/var/lib/mysql -e MYSQL_ROOT_PASSWORD=123456 mysql:5.7
19e93b6d93ca4e6ca0d540e3f6c831b835cdbb35362733867c3977aee4d33bf7
[root@localhost ~]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
19e93b6d93ca mysql:5.7 "docker-entrypoint..." 4 seconds ago Up 3 seconds 33060/tcp, 0.0.0.0:4345->3306/tcp mysql-10345
[root@localhost ~]# docker exec -it mysql-10345 /bin/bash
root@19e93b6d93ca:/# mysql -u root -p
Enter password:
设置【主库】信息
登录【从库
10345】,进入 mysql 命令行。
mysql> stop slave;
Query OK, 0 rows affected
mysql> CHANGE MASTER TO
MASTER_HOST='192.168.10.212',
MASTER_PORT=4300,
MASTER_USER='slave',
MASTER_PASSWORD='123456',
MASTER_LOG_FILE='mysql-bin.000003',
MASTER_LOG_POS=438
for channel '300';
Query OK, 0 rows affected
mysql> CHANGE MASTER TO
MASTER_HOST='192.168.10.212',
MASTER_PORT=4400,
MASTER_USER='slave',
MASTER_PASSWORD='123456',
MASTER_LOG_FILE='mysql-bin.000003',
MASTER_LOG_POS=438
for channel '400';
Query OK, 0 rows affected
mysql> CHANGE MASTER TO
MASTER_HOST='192.168.10.212',
MASTER_PORT=4500,
MASTER_USER='slave',
MASTER_PASSWORD='123456',
MASTER_LOG_FILE='mysql-bin.000003',
MASTER_LOG_POS=438
for channel '500';
Query OK, 0 rows affected
mysql> start slave;
Query OK, 0 rows affected
stop
slave; // 停止同步 start slave; // 开始同步 // 必须和【主库】的信息匹配。 CHANGE MASTER TO
MASTER_HOST=’192.168.10.212′, // 主库 IP MASTER_PORT=4300, // 主库端口
MASTER_USER=’slave’, // 访问主库且有同步复制权限的用户 MASTER_PASSWORD=’123456′, //
登录密码 //【关键处】从主库的该 log_bin
文件开始读取同步信息,主库 show master status
返回结果 MASTER_LOG_FILE=’mysql-bin.000003′, //【关键处】从文件中指定位置开始读取,主库 show master status
返回结果 MASTER_LOG_POS=438 **for channel ‘300’; //
定义通道名称 **
查看同步状态
mysql> show slave status /G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.10.212
Master_User: slave
Master_Port: 4300
Connect_Retry: 60
Master_Log_File: mysql-bin.000003
Read_Master_Log_Pos: 1860
Relay_Log_File: 0ad84f013600-relay-bin-300.000002
Relay_Log_Pos: 1742
Relay_Master_Log_File: mysql-bin.000003
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 1860
Relay_Log_Space: 1960
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 300
Master_UUID: 4efae154-ebd4-11e8-bf7d-0242ac110007
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name: 300
Master_TLS_Version:
*************************** 2. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.10.212
Master_User: slave
Master_Port: 4400
Connect_Retry: 60
Master_Log_File: mysql-bin.000003
Read_Master_Log_Pos: 2461
Relay_Log_File: 0ad84f013600-relay-bin-400.000002
Relay_Log_Pos: 1187
Relay_Master_Log_File: mysql-bin.000003
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 2461
Relay_Log_Space: 1405
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 400
Master_UUID: 8fb0aa81-ebd4-11e8-ac5b-0242ac110009
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name: 400
Master_TLS_Version:
*************************** 3. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.10.212
Master_User: slave
Master_Port: 4500
Connect_Retry: 60
Master_Log_File: mysql-bin.000003
Read_Master_Log_Pos: 2151
Relay_Log_File: 0ad84f013600-relay-bin-500.000002
Relay_Log_Pos: 626
Relay_Master_Log_File: mysql-bin.000003
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 2151
Relay_Log_Space: 844
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 500
Master_UUID: b87704d2-ebd5-11e8-a90c-0242ac11000a
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name: 500
Master_TLS_Version:
3 rows in set (0.00 sec)
可以看见设置三个的主从同步通道的所有状态信息。 只有【Slave_IO_Running】和【Slave_SQL_Running】都是
Yes,则同步是正常的。 如果是 No 或者 Connecting 都不行,可查看
mysql-error.log,以排查问题。
mysql> show variables like 'log_error%';
+---------------------+--------+
| Variable_name | Value |
+---------------------+--------+
| log_error | stderr |
| log_error_verbosity | 3 |
+---------------------+--------+
2 rows in set
配置完成,则【从库
10345】开始自动同步。
若需要单独启动或停止某个同步通道,可使用如下命令: start
slave for channel ‘300’; // 启动名称为 300 的同步通道 stop slave for channel ‘300’; //
停止名称为 300 的同步通道
验证数据同步
建库
使用
root 账号登录【主库 300】,创建 test3 数据库
mysql> CREATE DATABASE test3;
Query OK, 1 row affected (0.00 sec)
mysql> USE test3;
Database changed
建表
在【主库
300】中创建 user 表
CREATE TABLE `user` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`name` varchar(20) COLLATE utf8mb4_unicode_ci NOT NULL,
`age` tinyint(3) unsigned NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
新增
在【主库
300】中向 user 表插入一条数据:
mysql> use test3;
Database changed
mysql> INSERT INTO user (id, name, age) VALUES (300, 'Tom', 18);
Database changed
mysql> SELECT * FROM user;
+-----+------+-----+
| id | name | age |
+-----+------+-----+
| 300 | Tom | 18 |
+-----+------+-----+
1 row in set (0.00 sec)
在【从库
10345】中查询 user 表数据:
mysql> use test3;
Database changed
mysql> SELECT * FROM user;
+-----+------+-----+
| id | name | age |
+-----+------+-----+
| 300 | Tom | 18 |
+-----+------+-----+
1 row in set (0.00 sec)
新增记录同步成功。
更新
在【主库
300】中修改刚才插入的数据:
mysql> UPDATE user SET name='Peter' where id=300;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> select * from user;
+-----+-------+-----+
| id | name | age |
+-----+-------+-----+
| 300 | Peter | 18 |
+-----+-------+-----+
1 row in set (0.00 sec)
在【从库
10345】中查询 user 表数据:
mysql> select * from user;
+-----+-------+-----+
| id | name | age |
+-----+-------+-----+
| 300 | Peter | 18 |
+-----+-------+-----+
1 row in set (0.00 sec)
更新记录同步成功。
删除
在【主库
300】中删除刚才更新的数据:
mysql> DELETE FROM user WHERE id=300;
Query OK, 1 row affected (0.00 sec)
mysql> select * from user;
Empty set (0.00 sec)
在【从库
10345】中查询 user 表数据:
mysql> select * from user;
Empty set (0.00 sec)
删除记录同步成功。
注:【主库 400】、【主库 500】的验证操作与上述类似。
补充:
- 如果【主服务器】重启
mysql 服务,【从服务器】会等待与【主服务器】重连。当主服务器恢复正常后,从服务器会自动重新连接上主服务器,并正常同步数据。 - 如果某段时间内,【从数据库】服务器异常导致同步中断(可能是同步点位置不匹配),可以尝试以下恢复方法:进入【主数据库】服务器(正常),在
bin-log 中找到【从数据库】出错前的 position,然后在【从数据库】上执行 change master,将 master_log_file 和
master_log_pos 重新指定后,开始同步。 - 若是不需要同步,登录从库执行:stop
slave; - 若需要单独启动或停止某个同步通道,可使用如下命令:
start slave for channel ‘300’; // 启动名称为 300 的同步通道 stop slave for channel ‘300’;
// 停止名称为 300 的同步通道 - 通常多主一从,主库之间尽量不使用相同的
databaseName,避免冲突。
原创文章,作者:ItWorker,如若转载,请注明出处:https://blog.ytso.com/289618.html