MySQL多主一从（多源复制）同步配置

多主一从，也称为多源复制，数据流向

形式

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。（亦或者可以使用一键安装环境的插件，在这里不做详说）若不熟悉，可使用传统方式安装mysql，效果相同。

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=192.168.1.218; PORT=3306; server-id=2; database=test3; table=user
主库200：IP=192.168.1.225; PORT=3306; server-id=1; database=test4; table=user
从库：IP=192.168.1.128; PORT=3306; server-id=3; database=test3,test4; 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

【主库300】操作及配置

配置my.cnf

[client]
#password   = your_password
port        = 3306
socket      = /tmp/mysql.sock

[mysqld]
port        = 3306  #默认端口
socket      = /tmp/mysql.sock
datadir = /usr/local/mysql/var
skip-external-locking
key_buffer_size = 32M
max_allowed_packet = 1M
table_open_cache = 128
sort_buffer_size = 768K
net_buffer_length = 8K
read_buffer_size = 768K
read_rnd_buffer_size = 512K
myisam_sort_buffer_size = 8M
thread_cache_size = 16
query_cache_size = 16M
tmp_table_size = 32M
performance_schema_max_table_instances = 1000

skip-grant-tables

explicit_defaults_for_timestamp = true
#skip-networking
max_connections = 500
max_connect_errors = 100
open_files_limit = 65535

log-bin=mysql-bin    #开启二进制日志记录
binlog_format=mixed
server-id   = 3    #配置唯一id
expire_logs_days = 10    #日志过期时间（天）
early-plugin-load = ""

#不给从机同步的库
binlog-ignore-db=sys
binlog-ignore-db=mysql
binlog-ignore-db=information_schema
binlog-ignore-db=performance_schema

default_storage_engine = InnoDB
innodb_file_per_table = 1
innodb_data_home_dir = /usr/local/mysql/var
innodb_data_file_path = ibdata1:10M:autoextend
innodb_log_group_home_dir = /usr/local/mysql/var
innodb_buffer_pool_size = 128M
innodb_log_file_size = 32M
innodb_log_buffer_size = 8M
innodb_flush_log_at_trx_commit = 1
innodb_lock_wait_timeout = 50

创建授权用户

mysql重启，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 '用户名'@'%' IDENTIFIED BY '密码';#创建用户
mysql> GRANT REPLICATION SLAVE ON *.* TO '用户名'@'%';#分配权限
mysql>flush privileges;   #刷新权限

查看log_bin是否开启

mysql> show variables like 'log_bin';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_bin       | ON    |
+---------------+-------+
1 row in set (0.00 sec)

查看master状态，记录二进制文件名(mysql-bin.000006)和位置(916)

mysql> show master status;
+------------------+----------+--------------+-------------------------------------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB                                | Executed_Gtid_Set |
+------------------+----------+--------------+-------------------------------------------------+-------------------+
| mysql-bin.000006 |      916 |              | sys,mysql,information_schema,performance_schema |                   |
+------------------+----------+--------------+-------------------------------------------------+-------------------+
1 row in set (0.00 sec)

【主库400】配置及操作

配置my.cnf

[client]
#password   = your_password
port        = 3306
socket      = /tmp/mysql.sock

[mysqld]
port        = 3306
socket      = /tmp/mysql.sock
datadir = /usr/local/mysql/var
skip-external-locking
key_buffer_size = 32M
max_allowed_packet = 1M
table_open_cache = 128
sort_buffer_size = 768K
net_buffer_length = 8K
read_buffer_size = 768K
read_rnd_buffer_size = 512K
myisam_sort_buffer_size = 8M
thread_cache_size = 16
query_cache_size = 16M
tmp_table_size = 32M
performance_schema_max_table_instances = 1000

explicit_defaults_for_timestamp = true
#skip-networking
max_connections = 500
max_connect_errors = 100
open_files_limit = 65535

log-bin=mysql-bin    #开启二进制日志
binlog_format=mixed
server-id   = 1    #唯一id
expire_logs_days = 10    #过期日期（天）
early-plugin-load = ""

#不给从机同步的库
binlog-ignore-db=sys
binlog-ignore-db=mysql
binlog-ignore-db=information_schema
binlog-ignore-db=performance_schema

default_storage_engine = InnoDB
innodb_file_per_table = 1
innodb_data_home_dir = /usr/local/mysql/var
innodb_data_file_path = ibdata1:10M:autoextend
innodb_log_group_home_dir = /usr/local/mysql/var
innodb_buffer_pool_size = 128M
innodb_log_file_size = 32M
innodb_log_buffer_size = 8M
innodb_flush_log_at_trx_commit = 1
innodb_lock_wait_timeout = 50

[mysqldump]
quick
"/etc/my.cnf" 69L, 1430C

创建授权用户

mysql重启，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 '用户名'@'%' IDENTIFIED BY '密码';#创建用户
mysql> GRANT REPLICATION SLAVE ON *.* TO '用户名'@'%';#分配权限
mysql>flush privileges;   #刷新权限

注：各个主机创建的用户可以相同的。

查看log_bin是否开启

mysql> show variables like 'log_bin';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_bin       | ON    |
+---------------+-------+
1 row in set (0.00 sec)

查看master状态，记录二进制文件名(mysql-bin.000008)和位置(892)

mysql> show master status;
+------------------+----------+--------------+-------------------------------------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB                                | Executed_Gtid_Set |
+------------------+----------+--------------+-------------------------------------------------+-------------------+
| mysql-bin.000008 |      892 |              | sys,mysql,information_schema,performance_schema |                   |
+------------------+----------+--------------+-------------------------------------------------+-------------------+
1 row in set (0.00 sec)

【从库】配置及操作

配置my.cnf

[client]
#password   = your_password
port        = 3306
socket      = /tmp/mysql.sock

[mysqld]
port        = 3306
socket      = /tmp/mysql.sock
datadir = /usr/local/mysql/var
skip-external-locking
key_buffer_size = 32M
max_allowed_packet = 1M
table_open_cache = 128
sort_buffer_size = 768K
net_buffer_length = 8K
read_buffer_size = 768K
read_rnd_buffer_size = 512K
myisam_sort_buffer_size = 8M
thread_cache_size = 16
query_cache_size = 16M
tmp_table_size = 32M
performance_schema_max_table_instances = 1000

explicit_defaults_for_timestamp = true
#skip-networking
max_connections = 500
max_connect_errors = 100
open_files_limit = 65535

#log-bin=mysql-bin    #关闭二进制日志
binlog_format=mixed
server-id   = 2    #配置唯一id
expire_logs_days = 10    #过期时间（天）
early-plugin-load = ""

#加上以下参数避免更新不及时，slave 重启后导致的主从复制出错
read_only = 1
master_info_repository=TABLE
relay_log_info_repository=TABLE
relay_log_recovery=1 #从机禁止写操作

default_storage_engine = InnoDB
innodb_file_per_table = 1
innodb_data_home_dir = /usr/local/mysql/var
innodb_data_file_path = ibdata1:10M:autoextend
innodb_log_group_home_dir = /usr/local/mysql/var
innodb_buffer_pool_size = 128M
innodb_log_file_size = 32M
innodb_log_buffer_size = 8M
innodb_flush_log_at_trx_commit = 1
innodb_lock_wait_timeout = 50

[mysqldump]
quick
"/etc/my.cnf" 69L, 1494C

重启mysql，打开mysql会话，执行同步SQL语句(需要主服务器主机名，登陆凭据，二进制文件的名称和位置)：

mysql> CHANGE MASTER TO
    ->     MASTER_HOST='192.168.1.218',
    ->     MASTER_USER='用户名',
    ->     MASTER_PASSWORD='密码',
    ->     MASTER_LOG_FILE='mysql-bin.000006',
    ->     MASTER_LOG_POS=916
    ->     for channel '300';

mysql> CHANGE MASTER TO
    ->     MASTER_HOST='192.168.1.225',
    ->     MASTER_USER='用户名',
    ->     MASTER_PASSWORD='密码',
    ->     MASTER_LOG_FILE='mysql-bin.000008',
    ->     MASTER_LOG_POS=892
    ->     for channel '200';

关键点解说

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

启动slave同步进程

mysql>start slave;

查看同步状态

mysql> show slave status \G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.1.225
                  Master_User: root2
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000008
          Read_Master_Log_Pos: 892
               Relay_Log_File: localhost-relay-bin-200.000061
                Relay_Log_Pos: 320
        Relay_Master_Log_File: mysql-bin.000008
             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: 892
              Relay_Log_Space: 701
              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: 1
                  Master_UUID: 6c83a613-5cfe-11e9-92a0-000c29804965
             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: 200
           Master_TLS_Version: 
*************************** 2. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.1.218
                  Master_User: root3
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000006
          Read_Master_Log_Pos: 916
               Relay_Log_File: localhost-relay-bin-300.000065
                Relay_Log_Pos: 320
        Relay_Master_Log_File: mysql-bin.000006
             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: 916
              Relay_Log_Space: 701
              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: 3
                  Master_UUID: 164794cb-7557-11e9-bb7c-000c29b01621
             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 rows in set (0.00 sec)

ERROR: 
No query specified

可以看见设置两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，一般出错都是【MASTER_LOG_FILE】和【MASTER_LOG_POS】不一致问题，需要细细核查才行。

配置完成，则【从库】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

同步功能可自行验证（亲测有效）

参考

MySQL5.7多主一从（多源复制）同步配置

MySQL主从复制(Master-Slave)实践

MySQL多主一从（多源复制）同步配置

形式

应用场景

部署环境

配置约束

【主库300】操作及配置

【主库400】配置及操作

【从库】配置及操作

参考

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