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主主方案，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、 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）；
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)
第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#偶数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 statusG;
*************************** 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 statusG;
*************************** 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)