多主一從，也稱爲多源複製，數據流向：
主庫1 -> 從庫s
主庫2 -> 從庫s
主庫n -> 從庫s
應用場景
數據彙總，可將多個主數據庫同步彙總到一個從數據庫中，方便數據統計分析。
讀寫分離，從庫只用於查詢，提高數據庫整體性能。
部署環境
注：使用docker部署mysql實例，方便快速搭建演示環境。但本文重點是講解主從配置，因此簡略描述docker環境構建mysql容器實例。
數據庫：MySQL 5.7.x （相比5.5，5.6而言，5.7同步性能更好，支持多源複製，可實現多主一從，主從庫版本應保證一致）
操作系統：CentOS 7.x
容器：Docker 17.09.0-ce
鏡像：mysql:5.7
主庫300：IP=192.168.10.212; PORT=4300; server-id=300; database=test3; table=user
主庫400：IP=192.168.10.212; PORT=4400; server-id=400; database=test4; table=user
主庫500：IP=192.168.10.212; PORT=4500; server-id=500; database=test5; table=user
從庫10345：IP=192.168.10.212; PORT=4345; server-id=10345; database=test3,test4,test5; table=user
配置約束
主從庫必須保證網絡暢通可訪問
主庫必須開啓binlog日誌
主從庫的server-id必須不同
【主庫300】操作及配置
配置my.cnf
[client]port = 3306default-character-set = utf8mb4[mysql]port = 3306default-character-set = utf8mb4[mysqld]########################### summary###########################bind-address = 0.0.0.0#port = 3306#datadir=/datavol/mysql/data #數據存儲目錄########################### log bin##########################server-id = 300 #必須唯一log_bin = mysql-bin #開啓及設置二進制日誌文件名稱binlog_format = MIXEDsync_binlog = 1expire_logs_days =7 #二進制日誌自動刪除/過期的天數。默認值爲0，表示不自動刪除。#binlog_cache_size = 128m#max_binlog_cache_size = 512m#max_binlog_size = 256Mbinlog-do-db = test3 #要同步的數據庫binlog-ignore-db = mysql #不需要同步的數據庫 binlog_ignore_db = information_schemabinlog_ignore_db = performation_schemabinlog_ignore_db = sys ########################### character set##########################character-set-server = utf8mb4collation-server = utf8mb4_unicode_ci
安裝啓動
[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:5.75691bac538e646db00273e3cad5b350dbe6cce0bd176346b7eefd9a6f9e3a9ad [root@localhost ~]# docker psCONTAINER 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/bashroot@5691bac538e6:/# mysql -u root -pEnter password:
注：若不熟悉docker，可使用傳統方式安裝mysql，效果相同。
創建授權用戶
連接mysql主數據庫，鍵入命令mysql -u root -p，輸入密碼後登錄數據庫。創建用戶用於從庫同步複製，授予複製、同步訪問的權限
mysql> grant replication slave on *.* to 'slave'@'%' identified by '123456'; Query OK, 0 rows affected (0.00 sec)
log_bin是否開啓
mysql> show variables like 'log_bin'; +---------------+-------+| Variable_name | Value | +---------------+-------+| log_bin | ON | +---------------+-------+1 row in set
查看master狀態
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
【主庫400】配置及操作
配置my.cnf
[client]port = 3306default-character-set = utf8mb4[mysql]port = 3306default-character-set = utf8mb4[mysqld]########################### summary###########################bind-address = 0.0.0.0#port = 3306#datadir=/datavol/mysql/data #數據存儲目錄########################### log bin##########################server-id = 400 #必須唯一log_bin = mysql-bin #開啓及設置二進制日誌文件名稱binlog_format = MIXEDsync_binlog = 1expire_logs_days =7 #二進制日誌自動刪除/過期的天數。默認值爲0，表示不自動刪除。#binlog_cache_size = 128m#max_binlog_cache_size = 512m#max_binlog_size = 256Mbinlog-do-db = test4 #要同步的數據庫binlog-ignore-db = mysql #不需要同步的數據庫 binlog_ignore_db = information_schemabinlog_ignore_db = performation_schemabinlog_ignore_db = sys ########################### character set##########################character-set-server = utf8mb4collation-server = utf8mb4_unicode_ci
安裝啓動
[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:5.719e93b6d93ca4e6ca0d540e3f6c831b835cdbb35362733867c3977aee4d33bf7 [root@localhost ~]# docker psCONTAINER 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/bashroot@19e93b6d93ca:/# mysql -u root -pEnter password:
創建授權用戶
創建用戶用於從庫同步複製，授予複製、同步訪問的權限
mysql> grant replication slave on *.* to 'slave'@'%' identified by '123456'; Query OK, 0 rows affected (0.00 sec)
log_bin是否開啓
mysql> show variables like 'log_bin'; +---------------+-------+| Variable_name | Value | +---------------+-------+| log_bin | ON | +---------------+-------+1 row in set
查看master狀態
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
【主庫500】配置及操作
配置my.cnf
[client]port = 3306default-character-set = utf8mb4[mysql]port = 3306default-character-set = utf8mb4[mysqld]########################### summary###########################bind-address = 0.0.0.0#port = 3306#datadir=/datavol/mysql/data #數據存儲目錄########################### log bin##########################server-id = 500 #必須唯一log_bin = mysql-bin #開啓及設置二進制日誌文件名稱binlog_format = MIXEDsync_binlog = 1expire_logs_days =7 #二進制日誌自動刪除/過期的天數。默認值爲0，表示不自動刪除。#binlog_cache_size = 128m#max_binlog_cache_size = 512m#max_binlog_size = 256Mbinlog-do-db = test5 #要同步的數據庫binlog-ignore-db = mysql #不需要同步的數據庫 binlog_ignore_db = information_schemabinlog_ignore_db = performation_schemabinlog_ignore_db = sys ########################### character set##########################character-set-server = utf8mb4collation-server = utf8mb4_unicode_ci
安裝啓動
[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:5.719e93b6d93ca4e6ca0d540e3f6c831b835cdbb35362733867c3977aee4d33bf7 [root@localhost ~]# docker psCONTAINER 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/bashroot@19e93b6d93ca:/# mysql -u root -pEnter password:
創建授權用戶
創建用戶用於從庫同步複製，授予複製、同步訪問的權限
mysql> grant replication slave on *.* to 'slave'@'%' identified by '123456'; Query OK, 0 rows affected (0.00 sec)
log_bin是否開啓
mysql> show variables like 'log_bin'; +---------------+-------+| Variable_name | Value | +---------------+-------+| log_bin | ON | +---------------+-------+1 row in set
查看master狀態
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
【從庫10345】配置及操作
配置my.cnf
[client]port = 3306default-character-set = utf8mb4[mysql]port = 3306default-character-set = utf8mb4[mysqld]########################### summary###########################bind-address = 0.0.0.0#port = 3306#datadir=/datavol/mysql/data #數據存儲目錄########################### log bin##########################server-id = 10345master_info_repository = tablerelay_log_info_repository = table ########################### character set##########################character-set-server = utf8mb4collation-server = utf8mb4_unicode_ci
安裝啓動
[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:5.719e93b6d93ca4e6ca0d540e3f6c831b835cdbb35362733867c3977aee4d33bf7 [root@localhost ~]# docker psCONTAINER 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/bashroot@19e93b6d93ca:/# mysql -u root -pEnter password:
設置【主庫】信息
登錄【從庫10345】，進入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; //開始同步
//必須和【主庫】的信息匹配。
CHANGE MASTER TO
MASTER_HOST='192.168.10.212', //主庫IP
MASTER_PORT=4300, //主庫端口
MASTER_USER='slave', //訪問主庫且有同步複製權限的用戶
MASTER_PASSWORD='123456', //登錄密碼
//【關鍵處】從主庫的該log_bin文件開始讀取同步信息，主庫show master status返回結果
MASTER_LOG_FILE='mysql-bin.000003',
//【關鍵處】從文件中指定位置開始讀取，主庫show master status返回結果
MASTER_LOG_POS=438
for channel '300'; //定義通道名稱
查看同步狀態
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)
可以看見設置三個的主從同步通道的所有狀態信息。
只有【Slave_IO_Running】和【Slave_SQL_Running】都是Yes，則同步是正常的。
如果是No或者Connecting都不行，可查看mysql-error.log，以排查問題。
mysql> show variables like 'log_error%'; +---------------------+--------+| Variable_name | Value | +---------------------+--------+| log_error | stderr | | log_error_verbosity | 3 | +---------------------+--------+2 rows in set
配置完成，則【從庫10345】開始自動同步。
若需要單獨啓動或停止某個同步通道，可使用如下命令：
start slave for channel '300'; //啓動名稱爲300的同步通道
stop slave for channel '300'; //停止名稱爲300的同步通道
驗證數據同步
建庫
使用root賬號登錄【主庫300】，創建test3數據庫
mysql> CREATE DATABASE test3; Query OK, 1 row affected (0.00 sec) mysql> USE test3; Database changed
建表
在【主庫300】中創建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【主庫300】中向user表插入一條數據：
mysql> use test3;Database changedmysql> INSERT INTO user (id, name, age) VALUES (300, 'Tom', 18);Database changedmysql> SELECT * FROM user;+-----+------+-----+ | id | name | age | +-----+------+-----+ | 300 | Tom | 18 | +-----+------+-----+ 1 row in set (0.00 sec)
在【從庫10345】中查詢user表數據：
mysql> use test3; Database changed mysql> SELECT * FROM user; +-----+------+-----+| id | name | age |+-----+------+-----+| 300 | Tom | 18 |+-----+------+-----+1 row in set (0.00 sec)
新增記錄同步成功。
更新
在【主庫300】中修改剛纔插入的數據：
mysql> UPDATE user SET name='Peter' where id=300;Query OK, 1 row affected (0.01 sec) Rows matched: 1 Changed: 1 Warnings: 0mysql> select * from user;+-----+-------+-----+ | id | name | age | +-----+-------+-----+ | 300 | Peter | 18 | +-----+-------+-----+ 1 row in set (0.00 sec)
在【從庫10345】中查詢user表數據：
mysql> select * from user; +-----+-------+-----+| id | name | age |+-----+-------+-----+| 300 | Peter | 18 |+-----+-------+-----+1 row in set (0.00 sec)
更新記錄同步成功。
刪除
在【主庫300】中刪除剛纔更新的數據：
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【從庫10345】中查詢user表數據：
mysql> select * from user;Empty set (0.00 sec)
刪除記錄同步成功。
注：【主庫400】、【主庫500】的驗證操作與上述類似。
補充：
如果【主服務器】重啓mysql服務，【從服務器】會等待與【主服務器】重連。當主服務器恢復正常後，從服務器會自動重新連接上主服務器，並正常同步數據。
如果某段時間內，【從數據庫】服務器異常導致同步中斷（可能是同步點位置不匹配），可以嘗試以下恢復方法：進入【主數據庫】服務器（正常），在bin-log中找到【從數據庫】出錯前的position，然後在【從數據庫】上執行change master，將master_log_file和master_log_pos重新指定後，開始同步。
歡迎工作一到五年的Java工程師朋友們加入Java技術交流羣：659270626
羣內提供免費的Java架構學習資料（裏面有高可用、高併發、高性能及分佈式、Jvm性能調優、Spring源碼，MyBatis，Netty,Redis,Kafka,Mysql,Zookeeper,Tomcat,Docker,Dubbo,Nginx等多個知識點的架構資料）合理利用自己每一分每一秒的時間來學習提升自己，不要再用"沒有時間“來掩飾自己思想上的懶惰！趁年輕，使勁拼，給未來的自己一個交代！