mysql基础之mariadb集群双主(主主)架构

一、概念

  在企业中,数据库高可用一直是企业的重中之重,中小企业很多都是使用mysql主从方案,一主多从,读写分离等,但是单主存在单点故障,从库切换成主库需要作改动。因此,如果是双主或者多主,就会增加mysql入口,增加高可用。不过多主需要考虑自增长ID问题,这个需要特别设置配置文件,比如双主,可以使用奇偶,总之,主之间设置自增长ID相互不冲突就能完美解决自增长ID冲突问题。

单点故障解决方案:
  主主架构:
    互为主备,互相监控对方二进制日志文件进行同步
    note:当两个sql语句发生冲突的时候主主架构有可能出现数据不一致的现象;
  MHAmaster high availability):
    HMA可以有多个配置文件,一个配置文件监控一个主从架构

二、主主架构思路

1、两台mysql都可读可写,互为主备,默认只使用一台(masterA)负责数据的写入,另一台(masterB)备用;

2、masterA是masterB的主库,masterB又是masterA的主库,它们互为主从;

3、两台主库之间做高可用,可以采用keepalived等方案(使用VIP对外提供服务);

4、所有提供服务的从服务器与masterB进行主从同步(双主多从);

5、建议采用高可用策略的时候,masterA或masterB均不因宕机恢复后而抢占VIP(非抢占模式);

 三、演示步骤

环境(主1服务器端IP:192.168.11.7;主2服务器端IP:192.168.11.8)

1、修改配置文件,配置服务器编号,开启bin-log

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[root@bi7 ~]# vim /etc/my.cnf.d/server.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
server-id=7
log_bin=mysql-bin
binlog_format=row
relay-log=relay-mysql
relay-log-index=relay-mysql.index
log_slave_updates=on
auto-increment-increment=2
auto-increment-offset=1

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[root@bi8 ~]# vim /etc/my.cnf.d/server.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
server-id=8
log_bin=mysql-bin
binlog_format=row
relay-log=relay-mysql
relay-log-index=relay-mysql.index
log_slave_updates=on
auto-increment-increment=2
auto-increment-offset=2

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2、重启mysql服务(两台主机)

 systemctl restart mariadb
 ss -tnl |grep 3306
LISTEN     0      80          :::3306                    :::*

3、创建复制用的用户(两台主机)

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[root@bi8 ~]# mysql -uroot -proot
Welcome to the MariaDB monitor.  Commands end with ; or g.
Your MariaDB connection id is 9
Server version: 10.2.26-MariaDB-log MariaDB Server

Copyright c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or 'h' for help. Type 'c' to clear the curbit input statement.
MariaDB [none)]> grant replication slave on *.* to 'master'@'%' identified by '123';
Query OK, 0 rows affected 0.00 sec)

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4、(若第一次同步可忽略此步骤)这里可以清空两台主机的master和slave日志(若之前有开启过同步的,需要先停止同步:stop slave;)
在mysql命令行中输入:
  reset master;
  reset slave;

5、查看二进制日志文件的位置

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--主1 
MariaDB [none)]> show master status; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000001 | 1087 | | | +------------------+----------+--------------+------------------+ 1 row in set 0.00 sec)

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--主2
MariaDB [none)]> show master status; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000001 | 520 | | | +------------------+----------+--------------+------------------+ 1 row in set 0.00 sec)

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6、为防止配置同步的同时又数据写入,可给数据库加读锁(两台主机):

MariaDB [none)]> flush tables with read lock;
Query OK, 0 rows affected 0.00 sec)

7、两台服务器互相连接

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--主1连接主2
MariaDB [none)]> change master to master_host='192.168.11.8',master_user='master',master_password='123',master_log_file='mysql-bin.000001',master_log_pos=520;
Query OK, 0 rows affected 0.01 sec)
--主2连接主1
MariaDB [none)]> change master to master_host='192.168.11.7',master_user='master',master_password='123',master_log_file='mysql-bin.000001',master_log_pos=1087;
Query OK, 0 rows affected 0.05 sec)

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8、启动slave(两台主机)

MariaDB [none)]> start slave;
Query OK, 0 rows affected 0.01 sec)

9、检查连接状态(两台主机)

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MariaDB [none)]> show slave statusG;
*************************** 1. row ***************************
               Slave_IO_State: Connecting to master
                  Master_Host: 192.168.11.7
                  Master_User: master
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000001
          Read_Master_Log_Pos: 1087
               Relay_Log_File: relay-mysql.000001
                Relay_Log_Pos: 4
        Relay_Master_Log_File: mysql-bin.000001
             Slave_IO_Running: Connecting
            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: 1087
              Relay_Log_Space: 256
              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
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 2003
                Last_IO_Error: error connecting to master 'master@192.168.11.7:3306' - retry-time: 60  maximum-retries: 86400  message: Can't connect to MySQL server on '192.168.11.7' 113 "No route to host")
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 0
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
                   Using_Gtid: No
                  Gtid_IO_Pos: 
      Replicate_Do_Domain_Ids: 
  Replicate_Ignore_Domain_Ids: 
                Parallel_Mode: conservative
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
1 row in set 0.00 sec)

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10、添加防火墙规则

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[root@bi7 ~]# firewall-cmd --add-port=3306/tcp
success
[root@bi7 ~]# firewall-cmd --add-port=3306/tcp --permanent
success
[root@bi8 ~]# firewall-cmd --add-port=3306/tcp
success
[root@bi8 ~]# firewall-cmd --add-port=3306/tcp --permanent
success

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11、再次检查连接状态(两台主机)

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MariaDB [none)]> show slave statusG;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.11.8
                  Master_User: master
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000001
          Read_Master_Log_Pos: 520
               Relay_Log_File: relay-mysql.000002
                Relay_Log_Pos: 555
        Relay_Master_Log_File: mysql-bin.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: 520
              Relay_Log_Space: 860
              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: 8
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
                   Using_Gtid: No
                  Gtid_IO_Pos: 
      Replicate_Do_Domain_Ids: 
  Replicate_Ignore_Domain_Ids: 
                Parallel_Mode: conservative
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
1 row in set 0.00 sec)

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12、测试

--解锁(两台主机)
MariaDB [none)]> unlock tables; Query OK, 0 rows affected 0.00 sec)

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--查看主1的原本数据库
MariaDB [none)]> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | bi | +--------------------+ 4 rows in set 0.00 sec) --在主1上创建新库yang MariaDB [none)]> create database if not exists yang default character set utf8; Query OK, 1 row affected 0.00 sec)

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--查看主2是否有新建的数据库
MariaDB [none)]> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | yang | +--------------------+ 4 rows in set 0.10 sec)
--使用yang数据库 MariaDB [none)]> use yang; Database changed
--在主2上创建新表hello,并插入一条数据 MariaDB [yang]> create table helloid tinyint unsigned primary key auto_increment not null,name varchar20)); Query OK, 0 rows affected 0.03 sec) MariaDB [yang]> insert into hello values0,'李国祥'); Query OK, 1 row affected 0.00 sec) MariaDB [yang]> select * from hello; +----+-----------+ | id | name | +----+-----------+ | 2 | 李国祥 | +----+-----------+ 1 row in set 0.00 sec)

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--查看主1是否新插入的数据
MariaDB [none)]> use yang; Database changed MariaDB [yang]> select * from hello; +----+-----------+ | id | name | +----+-----------+ | 2 | 李国祥 | +----+-----------+ 1 row in set 0.01 sec)

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