mysql双主配置

测试环境：mysql8

注：MySQL双主需要配置默认跳过几条报错：1062,1053,1032,1146,1051,1050,ddl_exist_errors

1. 下载mysql，并初始化密码

已测试环境：centos7，centos8

注：yum下载mysql一般无初始密码，安装包下载一般密码在：/var/log/mysqld.log或/var/log/mysql/mysqld.log

 

 

2. 改配置

注1：使用mysql_native_password是为了方便配置密码

注2：以下配置是为了应对网络抖动引起的读写切换，防止短时间反复读写易位后产生主键冲突（比如写操作从节点一切换到节点二片刻后再次切回，节点二正在读取主键为100的数据，主键101排队，此时节点二成为主，写入主键101，102；此时节点一再次写入主键102。。。）；但是如此配置会导致主键不再连续

节点1：
auto-increment-increment=2
auto-increment-offset=1
节点2：
auto-increment-increment=2
auto-increment-offset=2

 

 

各节点详细配置如下：

节点一：

[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
log-error=/var/log/mysql/mysqld.log
pid-file=/run/mysqld/mysqld.pid

default-authentication-plugin=mysql_native_password
server-id=1
log-bin=no
binlog_format=mixed
relay-log=relay-bin
relay-log-index=slave-relay-bin.index
auto-increment-increment=2
auto-increment-offset=1
log-slave-updates
slave_skip_errors=1062,1053,1032,1146,1051,1050,ddl_exist_errors
sql_mode=STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION

节点二：

[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
log-error=/var/log/mysql/mysqld.log
pid-file=/run/mysqld/mysqld.pid

default-authentication-plugin=mysql_native_password
server-id=2
log-bin=on
binlog_format=mixed
relay-log=relay-bin
relay-log-index=slave-relay-bin.index
auto-increment-increment=2
auto-increment-offset=2
log-slave-updates
slave_skip_errors=1062,1053,1032,1146,1051,1050,ddl_exist_errors
sql_mode=STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION

 

改完配置后，重启数据库

systemctl restart mysqld

 

3. 创建共享用户，并配置同步

两个节点同时执行以下命令

CREATE USER share@'%' IDENTIFIED BY 'Admin123!';
GRANT REPLICATION SLAVE ON *.* to share@'%';
reset master;
change master to master_host='192.168.202.10',master_port=3306,master_user='share',master_password='Admin123!';

 

4. 验证

show master status;
show slave status\G

示例

注意：

Slave_IO_Running: Yes

Slave_SQL_Running: Yes

#横向看主（数据少）
mysql> show master status; 
+-----------+----------+--------------+------------------+-------------------+
| File      | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+-----------+----------+--------------+------------------+-------------------+
| no.000001 |     4054 |              |                  |                   |
+-----------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

#纵向看从（数据太多）
mysql> show master status\G  
*************************** 1. row ***************************
             File: no.000001
         Position: 4054
     Binlog_Do_DB: 
 Binlog_Ignore_DB: 
Executed_Gtid_Set: 
1 row in set (0.00 sec)

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for source to send event
                  Master_Host: 192.168.202.10
                  Master_User: share
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: on.000001
          Read_Master_Log_Pos: 4103
               Relay_Log_File: relay-bin.000002
                Relay_Log_Pos: 1213
        Relay_Master_Log_File: on.000001
             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: 4103
              Relay_Log_Space: 1416
              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: 2
                  Master_UUID: 58a1741a-a12c-11ed-8177-0050569c7c4a
             Master_Info_File: mysql.slave_master_info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Replica 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: 
       Master_public_key_path: 
        Get_master_public_key: 0
            Network_Namespace: 
1 row in set, 1 warning (0.01 sec)

mysql> 

 

5. 测试示例

1）从任意节点建库建表，两个节点上的库表都能同步

create database if not exists testdb1;
create table testdb1.table01(
id INT UNSIGNED AUTO_INCREMENT primary key,
name VARCHAR(100) NOT NULL,
sex VARCHAR(40) NOT NULL,
age smallint,
salary int default 0
);
insert into testdb1.table01(name,sex,age,salary) values('tom','man',18,9000);
delete from testdb1.table01 where name='tom';
drop table testdb1.table01;
drop database testdb1;

验证

show databases;
show tables from testdb1;
desc testdb1.table01;
select * from testdb1.table01;