mysql实现主从复制

February 19, 2019 - 7 min read

基本流程

docker-compose.yml文件配置

#数据库-主库
    mysql57:
        image: ${MYSQL_IMAGE}
        environment:
            - MYSQL_ROOT_PASSWORD=${MYSQL_MASTER_ROOT_PASSWORD}
            #- MYSQL_USER=user
            #- MYSQL_PASSWORD=password
        volumes:
            #配置文件
            - ${MYSQL_MASTER_CONF}:/etc/mysql/my.cnf:ro
            #数据目录
            - ${MYSQL_MASTER_DATA}:/var/lib/mysql/:rw
            #查询日志文件
            #- ./logs/mysql/query_mysql.log:/var/logs/mysql/query.mysql.log:rw
            #慢查询日志文件
            #- ./logs/mysql/slow_mysql.log:/var/logs/mysql/slow.mysql.log:rw
        restart: always
        ports:
            - "${MYSQL_MASTER_PORT}:3306"
        container_name: mysql57
    #从库01
    mysql57-slave01:
       depends_on:
           - mysql57
       image: ${MYSQL_IMAGE}
       environment:
           - MYSQL_ROOT_PASSWORD=${MYSQL_SLAVE_01_ROOT_PASSWORD}
           - MASTER_HOST=mysql57
           #- MYSQL_USER=user
           #- MYSQL_PASSWORD=password
       volumes:
           #配置文件
           - ${MYSQL_SLAVE_01_CONF}:/etc/mysql/my.cnf:ro
           #数据目录
           - ${MYSQL_SLAVE_01_DATA}:/var/lib/mysql/:rw
           #查询日志文件
           #- ./logs/mysql/query_mysql.log:/var/logs/mysql/query.mysql.log:rw
           #慢查询日志文件
           #- ./logs/mysql/slow_mysql.log:/var/logs/mysql/slow.mysql.log:rw
       restart: always
       ports:
           - "${MYSQL_SLAVE_01_PORT}:3306"
       container_name: mysql57-slave01
    #从库02
    mysql57-slave02:
       depends_on:
           - mysql57
       image: ${MYSQL_IMAGE}
       environment:
           - MYSQL_ROOT_PASSWORD=${MYSQL_SLAVE_02_ROOT_PASSWORD}
           - MASTER_HOST=mysql57
           #- MYSQL_USER=user
           #- MYSQL_PASSWORD=password
       volumes:
           #配置文件
           - ${MYSQL_SLAVE_02_CONF}:/etc/mysql/my.cnf:ro
           #数据目录
           - ${MYSQL_SLAVE_02_DATA}:/var/lib/mysql/:rw
           #查询日志文件
           #- ./logs/mysql/query_mysql.log:/var/logs/mysql/query.mysql.log:rw
           #慢查询日志文件
           #- ./logs/mysql/slow_mysql.log:/var/logs/mysql/slow.mysql.log:rw
       restart: always
       ports:
           - "${MYSQL_SLAVE_02_PORT}:3306"
       container_name: mysql57-slave02

master配置

my.cnf文件加入:

## 设置server_id，一般设置为IP，同一局域网内注意要唯一
server_id=id1
## 复制过滤：也就是指定哪个数据库不用同步（mysql库一般不同步）
binlog-ignore-db=mysql
## 开启二进制日志功能，可以随便取，最好有含义（关键就是这里了）
log-bin=community-mysql-bin
## 为每个session 分配的内存，在事务过程中用来存储二进制日志的缓存
binlog_cache_size=1M
## 主从复制的格式（mixed,statement,row，默认格式是statement）
binlog_format=mixed
## 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。
expire_logs_days=7
## 跳过主从复制中遇到的所有错误或指定类型的错误，避免slave端复制中断。
## 如：1062错误是指一些主键重复，1032错误是因为主从数据库数据不一致
slave_skip_errors=1062

重启master

service mysql restart

查看master状态

mysql> show master status \G;

得到类似:

*************************** 1. row ***************************
             File: community-mysql-bin.000003
         Position: 50759
     Binlog_Do_DB:
 Binlog_Ignore_DB: mysql
Executed_Gtid_Set:
1 row in set (0.00 sec)

master库创建slave用户

CREATE USER 'slave01'@'%' IDENTIFIED BY 'password';
GRANT REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'slave01'@'%';
CREATE USER 'slave02'@'%' IDENTIFIED BY 'password';
GRANT REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'slave02'@'%';

slave配置

my.cnf文件加入:

## 设置server_id,唯一
server_id=id2
## 复制过滤：也就是指定哪个数据库不用同步（mysql库一般不同步）
binlog-ignore-db=mysql
## 开启二进制日志功能，以备Slave作为其它Slave的Master时使用
log-bin=community-mysql-slave-bin
## 为每个session 分配的内存，在事务过程中用来存储二进制日志的缓存
binlog_cache_size=1M
## 主从复制的格式（mixed,statement,row，默认格式是statement）
binlog_format=mixed
## 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。
expire_logs_days=7
## 跳过主从复制中遇到的所有错误或指定类型的错误，避免slave端复制中断。
## 如：1062错误是指一些主键重复，1032错误是因为主从数据库数据不一致
slave_skip_errors=1062
## relay_log配置中继日志
relay_log=community-mysql-relay-bin
## log_slave_updates表示slave将复制事件写进自己的二进制日志
log_slave_updates=1
## 防止改变数据(除了特殊的线程)
read_only=1

重启slave

service mysql restart

查看slave状态

show slave status \G;

连接master服务器

-- 两个从库分别配置主库
change master to master_host='mysql57',master_user='slave01',master_password='password',master_port=port,master_log_file='master库的master_log_file文件:上面通过`show master status`得到的File字段',master_log_pos=0;  
change master to master_host='mysql57',master_user='slave02',master_password='password',master_port=port,master_log_file='master库的master_log_file文件:上面通过`show master status`得到的File字段',master_log_pos=0;
-- 开启同步
start slave;
-- 查看状态
show slave status \G;

显示类似内容:

*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: mysql57
                  Master_User: slave
                  Master_Port: 3306
                Connect_Retry: 30
              Master_Log_File: community-mysql-bin.000003
          Read_Master_Log_Pos: 51273
               Relay_Log_File: community-mysql-relay-bin.000002
                Relay_Log_Pos: 51506
        Relay_Master_Log_File: community-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: 51273
              Relay_Log_Space: 51723
              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: 100
                  Master_UUID: 9d09b11c-fdeb-11e8-8ac4-0242ac140006
             Master_Info_File: /var/lib/mysql/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:
           Master_TLS_Version:
1 row in set (0.00 sec)

如果Slave_IO_Running,Slave_SQL_Running不为YES,则排查以上步骤是否正确

至此配置完成

laravel中相关配置

在config/database.php中mysql段配置如下:

'mysql' => [
    'read' => [
        'host' => env('DB_SLAVE_HOST', '127.0.0.1'),
    ],
    'write' => [
        'host' => env('DB_HOST', '127.0.0.1'),
    ],
    'sticky'    => true,
    'driver'    => 'mysql',
    'database' => env('DB_DATABASE', ''),
    'username' => env('DB_USERNAME', ''),
    'password' => env('DB_PASSWORD', ''),
    'unix_socket' => env('DB_SOCKET', ''),
    'charset' => 'utf8mb4',
    'collation' => 'utf8mb4_general_ci',
    'prefix'    => '',
    'strict' => false,
    'engine' => null,
],

注意

如果是线上操作(持续有数据写入),则需要按照以下步骤：master锁表-->master备份数据-->master解锁表 -->slave导入数据-->slave设置主从-->查看主从
如果多个从库需要注意
1. 数据目录auto.cnf中的server-uuid唯一
2. 配置文件my.cnf中的server_id唯一
需要在从库的容器环境变量中添加MASTER_HOST=主节点容器名称来确保容器重启之后自动同步主库binlog

错误修复

如果遇到类似以下错误,可能是由于主从库之间结构不同或其他原因造成的SQL query执行失败

mysql> SHOW SLAVE STATUS \G
*************************** 1. row ***************************
             Slave_IO_State: Waiting for master to send event
                Master_Host: 1.2.3.4
                Master_User: slave_user
                Master_Port: 3306
              Connect_Retry: 60
            Master_Log_File: mysql-bin.001079
        Read_Master_Log_Pos: 269214454
             Relay_Log_File: slave-relay.000130
              Relay_Log_Pos: 100125935
      Relay_Master_Log_File: mysql-bin.001079
           Slave_IO_Running: Yes
          Slave_SQL_Running: No
            Replicate_Do_DB: mydb
        Replicate_Ignore_DB:
         Replicate_Do_Table:
     Replicate_Ignore_Table:
    Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
                 Last_Errno: 1146
                 Last_Error: Error 'Table 'mydb.taggregate_temp_1212047760' doesn't exist' on query. Default database: 'mydb'. 
Query: 'UPDATE thread AS thread,taggregate_temp_1212047760 AS aggregate
        SET thread.views = thread.views + aggregate.views
        WHERE thread.threadid = aggregate.threadid'
               Skip_Counter: 0
        Exec_Master_Log_Pos: 203015142
            Relay_Log_Space: 166325247
            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: NULL
1 row in set (0.00 sec)

可以通过以下步骤跳过错误

mysql> stop slave;-- 停止
mysql> SET GLOBAL SQL_SLAVE_SKIP_COUNTER = 1;-- 跳过指定数量的SQL query,此处为1条
mysql> start slave;-- 开启
mysql> show slave status \G;-- 状态
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: mysql57
                  Master_User: slave
                  Master_Port: 3306
                Connect_Retry: 30
              Master_Log_File: community-mysql-bin.000005
          Read_Master_Log_Pos: 2145
               Relay_Log_File: community-mysql-relay-bin.000010
                Relay_Log_Pos: 330
        Relay_Master_Log_File: community-mysql-bin.000005
             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: 2145
              Relay_Log_Space: 2771
              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: 100
                  Master_UUID: c28b993e-368d-11e9-96c4-0242ac120002
             Master_Info_File: /var/lib/mysql/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:
           Master_TLS_Version:
1 row in set (0.00 sec)

ERROR:
No query specified