MySQL主主同步方案

2019/10/21 19:17
阅读数 5

MySQL主主同步方案

l MySQL主主+Keepalived

l MySQL+DRBD+Heartbeat

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。

 

主主方案实现思路

1、 两台mysql都可读写,互为主备默认只使用一台masterA负责数据的写入,另一台masterB备用处于备用状态

2、 masterAmasterB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,masterAmasterB均不因宕机恢复后而抢占VIP(非抢占模式);

这样做可以在一定程度上保证主库的高可用,在一台主库down掉之后,可以在极短的时间内切换到另一台主库上尽可能减少主库宕机对业务造成的影响,减少了主从同步给生产主库带来的压力;

 

但是也有几个不足的地方:

  • masterB可能会一直处于空闲状态(可以用它当从库,负责部分查询);
  • 主库后面提供服务的从库要等masterB先同步完了数据后才能去masterB上去同步数据,这样可能会造成一定程度的同步延时;

 

 

第1台机器

[root@localhost ~]# vim /etc/my.cnf

[mysqld]

server-id=1

log-bin=mysql-binlog#打开二进制功能

log-slave-updates=true

max_binlog_size=1024M#binlog单文件最大值

auto_increment_offset = 1

auto_increment_increment = 2#奇数ID

 

replicate-ignore-db = information_schema#忽略不同步主从的数据库

replicate-ignore-db = performance_schema

replicate-ignore-db = test

replicate-ignore-db = mysql

 

max_connections = 3000

max_connect_errors = 30

 

skip-character-set-client-handshake#忽略应用程序想要设置的其他字符集

init-connect='SET NAMES utf8'#连接时执行的SQL

character-set-server=utf8#服务端默认字符集

wait_timeout=1800#请求的最大连接时间

interactive_timeout=1800#和上一参数同时修改才会生效

sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES#sql模式

 

relay-log=relay-log-bin#开启中继日志

relay-log-index=slave-relay-bin.index

[root@localhost ~]# systemctl restart mariadb

[root@localhost ~]# mysql

MariaDB [(none)]> grant replication slave on *.* to 'repl'@'192.168.200.112' identified by '123456';

Query OK, 0 rows affected (0.00 sec)

 

MariaDB [(none)]> flush privileges;

Query OK, 0 rows affected (0.00 sec)

 

MariaDB [(none)]> show master status;

+---------------------+----------+--------------+------------------+

| File                | Position | Binlog_Do_DB | Binlog_Ignore_DB |

+---------------------+----------+--------------+------------------+

| mysql-binlog.000004 |      486 |              |                  |

+---------------------+----------+--------------+------------------+

1 row in set (0.00 sec)

 

2台机器

[root@localhost ~]# cat /etc/my.cnf

[mysqld]

server-id       = 2

log-bin=mysql-binlog

log-slave-updates=true

max_binlog_size=1024M

auto_increment_offset = 2

auto_increment_increment = 2#ID

 

replicate-ignore-db = information_schema

replicate-ignore-db = performance_schema

replicate-ignore-db = test

replicate-ignore-db = mysql

 

max_connections = 3000

max_connect_errors = 30

 

skip-character-set-client-handshake

init-connect='SET NAMES utf8'

character-set-server=utf8

wait_timeout=1800

interactive_timeout=1800

sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES

 

relay-log=relay-log-bin

relay-log-index=slave-relay-bin.index

[root@localhost ~]# systemctl restart mariadb

[root@localhost ~]# mysql

MariaDB [(none)]> grant replication slave on *.* to 'repl'@'192.168.200.111' identified by '123456';

Query OK, 0 rows affected (0.00 sec)

 

MariaDB [(none)]> flush privileges;

Query OK, 0 rows affected (0.00 sec)

 

MariaDB [(none)]> show master status;

+---------------------+----------+--------------+------------------+

| File                | Position | Binlog_Do_DB | Binlog_Ignore_DB |

+---------------------+----------+--------------+------------------+

| mysql-binlog.000001 |      889 |              |                  |

+---------------------+----------+--------------+------------------+

1 row in set (0.00 sec)

特别参数说明

log-slave-updates = true     #将复制事件写入binlog,一台服务器既做主库又做从库此选项必须要开启

masterA自增长ID

auto_increment_offset = 1

auto_increment_increment = 2    #奇数ID

masterB自增加ID

auto_increment_offset = 2

auto_increment_increment = 2    #偶数ID

 

测试环境,可以保证没数据写入否则需要的步骤是:先masterA锁表-->masterA备份数据-->masterA解锁表 -->masterB导入数据-->masterB设置主从-->查看主从

第1台机器

MariaDB [(none)]> stop slave;

Query OK, 0 rows affected, 1 warning (0.00 sec)

 

MariaDB [(none)]> change master to master_host='192.168.200.112',master_port=3306,master_user='repl',master_password='123456',master_log_file='mysql-binlog.000001',master_log_pos=889;

Query OK, 0 rows affected (0.04 sec)

 

MariaDB [(none)]> start slave;

Query OK, 0 rows affected (0.01 sec)

MariaDB [(none)]> show slave status\G;

*************************** 1. row ***************************

               Slave_IO_State: Waiting for master to send event

                  Master_Host: 192.168.200.112

                  Master_User: repl

                  Master_Port: 3306

                Connect_Retry: 60

              Master_Log_File: mysql-binlog.000001

          Read_Master_Log_Pos: 889

               Relay_Log_File: relay-log-bin.000002

                Relay_Log_Pos: 532

        Relay_Master_Log_File: mysql-binlog.000001

             Slave_IO_Running: Yes

            Slave_SQL_Running: Yes

 

第2台机器

MariaDB [(none)]> stop slave;

Query OK, 0 rows affected (0.01 sec)

 

MariaDB [(none)]> change master to master_host='192.168.200.111',master_port=3306,master_user='repl',master_password='123456',master_log_file='mysql-binlog.000004',master_log_pos=486;

Query OK, 0 rows affected (0.13 sec)

 

MariaDB [(none)]> start slave;

Query OK, 0 rows affected (0.01 sec)

 

MariaDB [(none)]> show slave status\G;

*************************** 1. row ***************************

               Slave_IO_State: Waiting for master to send event

                  Master_Host: 192.168.200.111

                  Master_User: repl

                  Master_Port: 3306

                Connect_Retry: 60

              Master_Log_File: mysql-binlog.000004

          Read_Master_Log_Pos: 486

               Relay_Log_File: relay-log-bin.000002

                Relay_Log_Pos: 532

        Relay_Master_Log_File: mysql-binlog.000004

             Slave_IO_Running: Yes

            Slave_SQL_Running: Yes

 

第1台机器

MariaDB [(none)]> create database test01;

Query OK, 1 row affected (0.01 sec)

 

第2台机器

MariaDB [(none)]> show databases;

+--------------------+

| Database           |

+--------------------+

| information_schema |

| mysql              |

| performance_schema |

| test               |

| test01             |

+--------------------+

5 rows in set (0.00 sec)

 

MariaDB [(none)]> create database test02;

Query OK, 1 row affected (0.00 sec)

 

第1台机器

MariaDB [(none)]> show databases;

+--------------------+

| Database           |

+--------------------+

| information_schema |

| mysql              |

| performance_schema |

| test               |

| test01             |

| test02             |

+--------------------+

6 rows in set (0.00 sec)

MySQL主主高可用方案

masterA配置

[root@localhost ~]# yum -y install keepalived

[root@localhost ~]# cat /etc/keepalived/keepalived.conf

! Configuration File for keepalived

 

global_defs {

   router_id LVS_MASTER-A

}

 

vrrp_script mysql {

    script "/opt/mysql.sh"

    interval 2

    weight -5                 

    fall 2                 

    rise 1

}

 

vrrp_instance VI_1 {

    state BACKUP

    interface ens32

    virtual_router_id 51

priority 100

nopreempt

    advert_int 1

    authentication {

        auth_type PASS

        auth_pass 1111

    }

    track_script {

        mysql

    }

    virtual_ipaddress {

        192.168.200.254

    }

}

[root@localhost ~]# cat /opt/mysql.sh

#!/bin/bash

counter=$(netstat -na|grep "LISTEN"|grep "3306"|wc -l)

if [ "${counter}" -eq 0 ]; then

    systemctl stop keepalived

fi

[root@localhost ~]# chmod +x /opt/mysql.sh

[root@localhost ~]# systemctl start keepalived

[root@localhost ~]# ip a | grep ens32

2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000

    inet 192.168.200.111/24 brd 192.168.200.255 scope global ens32

inet 192.168.200.254/32 scope global ens32

 

[root@localhost ~]# tail -f /var/log/messages

Feb 12 17:23:23 localhost Keepalived_vrrp[70087]: VRRP_Instance(VI_1) Transition to MASTER STATE

Feb 12 17:23:24 localhost Keepalived_vrrp[70087]: VRRP_Instance(VI_1) Entering MASTER STATE

Feb 12 17:23:24 localhost Keepalived_vrrp[70087]: VRRP_Instance(VI_1) setting protocol iptable drop rule

Feb 12 17:23:24 localhost Keepalived_vrrp[70087]: VRRP_Instance(VI_1) setting protocol VIPs.

Feb 12 17:23:24 localhost Keepalived_vrrp[70087]: Sending gratuitous ARP on ens32 for 192.168.200.254

Feb 12 17:23:24 localhost Keepalived_vrrp[70087]: VRRP_Instance(VI_1) Sending/queueing gratuitous ARPs on ens32 for 192.168.200.254

Feb 12 17:23:24 localhost Keepalived_vrrp[70087]: Sending gratuitous ARP on ens32 for 192.168.200.254

masterB配置

[root@localhost ~]# cat /etc/keepalived/keepalived.conf

! Configuration File for keepalived

 

global_defs {

   router_id LVS_MASTER-B

}

 

vrrp_script mysql {

    script "/opt/mysql.sh"

    interval 2

    weight -5                 

    fall 2                 

    rise 1

}

 

vrrp_instance VI_1 {

    state BACKUP

    interface ens32

    virtual_router_id 51

    priority 99

    advert_int 1

    authentication {

        auth_type PASS

        auth_pass 1111

    }

    track_script {

        mysql

    }

    virtual_ipaddress {

        192.168.200.254

    }

}

[root@localhost ~]# cat /opt/mysql.sh

#!/bin/bash

counter=$(netstat -na|grep "LISTEN"|grep "3306"|wc -l)

if [ "${counter}" -eq 0 ]; then

    systemctl stop keepalived

fi

[root@localhost ~]# chmod +x /opt/mysql.sh

[root@localhost ~]# systemctl start keepalived

[root@localhost ~]# tail -f /var/log/messages

Feb 12 17:28:02 localhost Keepalived_healthcheckers[70075]: WARNING - script '/root/shutdown.sh' is not executable for uid:gid 0:0 - disabling.

Feb 12 17:28:02 localhost Keepalived_healthcheckers[70075]: SECURITY VIOLATION - check scripts are being executed but script_security not enabled.

Feb 12 17:28:02 localhost kernel: ip_set: protocol 6

Feb 12 17:28:02 localhost kernel: IPVS: [wrr] scheduler registered.

Feb 12 17:28:02 localhost Keepalived_healthcheckers[70075]: Activating healthchecker for service [192.168.200.254]:3306

Feb 12 17:28:02 localhost Keepalived_vrrp[70076]: VRRP_Instance(VI_1) removing protocol VIPs.

Feb 12 17:28:02 localhost Keepalived_vrrp[70076]: VRRP_Instance(VI_1) removing protocol iptable drop rule

Feb 12 17:28:02 localhost Keepalived_vrrp[70076]: Using LinkWatch kernel netlink reflector...

Feb 12 17:28:02 localhost Keepalived_vrrp[70076]: VRRP_Instance(VI_1) Entering BACKUP STATE

Feb 12 17:28:02 localhost Keepalived_vrrp[70076]: VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)]

 

1、 测试VIP转移

masterA配置

[root@localhost ~]# systemctl stop mariadb

[root@localhost ~]# ip a | grep ens32

2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000

    inet 192.168.200.111/24 brd 192.168.200.255 scope global ens32

[root@localhost ~]# ps aux | grep mysql

root      83651  0.0  0.0 112720   980 pts/2    S+   14:30   0:00 grep --color=auto mysql

masterB配置

[root@localhost ~]# ip a | grep ens32

2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000

    inet 192.168.200.112/24 brd 192.168.200.255 scope global ens32

inet 192.168.200.254/32 scope global ens32

 

[root@localhost ~]# tail -f /var/log/messages

Feb 13 14:30:02 localhost Keepalived_vrrp[79095]: VRRP_Instance(VI_1) Entering MASTER STATE

Feb 13 14:30:02 localhost Keepalived_vrrp[79095]: VRRP_Instance(VI_1) setting protocol VIPs.

Feb 13 14:30:02 localhost Keepalived_vrrp[79095]: Sending gratuitous ARP on ens32 for 192.168.200.254

Feb 13 14:30:02 localhost Keepalived_vrrp[79095]: VRRP_Instance(VI_1) Sending/queueing gratuitous ARPs on ens32 for 192.168.200.254

 

2、 在远程客户端测试

mysql服务器授权

[root@localhost ~]# mysql -uroot

MariaDB [(none)]> grant all on *.* to 'root'@'192.168.200.%' identified by '123456';

MariaDB [(none)]> flush privileges;

通过vip登陆测试

[root@localhost ~]# mysql -uroot -p123456 -h 192.168.200.254

Welcome to the MariaDB monitor.  Commands end with ; or \g.

Your MariaDB connection id is 5796

Server version: 5.5.56-MariaDB MariaDB Server

 

Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.

 

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

 

MariaDB [(none)]> show databases;

+--------------------+

| Database           |

+--------------------+

| information_schema |

| mysql              |

| performance_schema |

| test               |

| test01             |

| test02             |

+--------------------+

6 rows in set (0.00 sec)

 

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