前言：
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因为主2，从2，都是通过同一个镜像生成的系统，所以mysql的 server-uuid 是一样的，在配置前，需要做以下操作
重命名 /var/lib/mysql/auto.cnf 文件
mv auto.cnf auto.cnf.bak
重启mysql 重新生成 auto.cnf 文件
因为之前配置过 ali-shuidi01,ali-shuidi02的主从关系，所以先将两者之前的主从关系取消，在master1上执行
mysql> stop slave;Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> reset master;Query OK, 0 rows affected (0.01 sec)
2. master1 配置文件修改
vim /etc/my.cnf
#主服务器唯一IDserver-id=1#启用二进制日志log-bin=mysql-bin# 设置不要复制的数据库(可设置多个)binlog-ignore-db=mysqlbinlog-ignore-db=information_schemabinlog-ignore-db=performance_schemabinlog-ignore-db=sys#设置需要复制的数据库binlog-do-db=copydb2#设置logbin格式binlog_format=STATEMENT# 在作为从数据库的时候，有写入操作也要更新二进制日志文件log-slave-updates#表示自增长字段每次递增的量，指自增字段的起始值，其默认值是1，取值范围是1 .. 65535auto-increment-increment=2# 表示自增长字段从哪个数开始，指字段一次递增多少，他的取值范围是1 .. 65535auto-increment-offset=1
3. master2 配置文件修改
vim /etc/my.cnf
#主服务器唯一IDserver-id=3#启用二进制日志log-bin=mysql-bin# 设置不要复制的数据库(可设置多个)binlog-ignore-db=mysqlbinlog-ignore-db=information_schemabinlog-ignore-db=performance_schemabinlog-ignore-db=sys#设置需要复制的数据库binlog-do-db=copydb2#设置logbin格式binlog_format=STATEMENT# 在作为从数据库的时候，有写入操作也要更新二进制日志文件log-slave-updates#表示自增长字段每次递增的量，指自增字段的起始值，其默认值是1，取值范围是1 .. 65535auto-increment-increment=2# 表示自增长字段从哪个数开始，指字段一次递增多少，他的取值范围是1 .. 65535auto-increment-offset=2
4. slave1 配置文件修改
vim /etc/my.cnf
#从服务器唯一IDserver-id=2#启用中继日志relay-log=mysql-relay
5. slave2配置文件修改
vim /etc/my.cnf
#从服务器唯一IDserver-id=4 #启用中继日志relay-log=mysql-relay
6. 双主机、双从机重启 mysql 服务, 主机从机都关闭防火墙
[root@shuidi01 etc]# systemctl restart mysqld[root@shuidi01 etc]# systemctl status mysqld● mysqld.service - MySQL ServerLoaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)Active: active (running) since 一 2020-03-30 20:38:23 CST; 6s agoDocs: man:mysqld(8)Process: 9985 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)Process: 9946 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)Main PID: 9990 (mysqld)CGroup: /system.slice/mysqld.service└─9990 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
3月 30 20:38:22 shuidi01 systemd[1]: Starting MySQL Server...3月 30 20:38:23 shuidi01 systemd[1]: Started MySQL Server.
[root@shuidi02 etc]# systemctl restart mysqld[root@shuidi02 etc]# systemctl status mysqld● mysqld.service - MySQL ServerLoaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)Active: active (running) since 一 2020-03-30 20:39:10 CST; 7s agoDocs: man:mysqld(8)Process: 868 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)Process: 845 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)Main PID: 873 (mysqld)CGroup: /system.slice/mysqld.service└─873 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
3月 30 20:39:09 shuidi02 systemd[1]: Starting MySQL Server...3月 30 20:39:10 shuidi02 systemd[1]: Started MySQL Server.
[root@shuidi03 etc]# systemctl restart mysqld[root@shuidi03 etc]# systemctl status mysqld● mysqld.service - MySQL ServerLoaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)Active: active (running) since 一 2020-03-30 20:39:42 CST; 5s agoDocs: man:mysqld(8)Process: 8507 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)Process: 8485 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)Main PID: 8512 (mysqld)CGroup: /system.slice/mysqld.service└─8512 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
3月 30 20:39:41 shuidi03 systemd[1]: Starting MySQL Server...3月 30 20:39:42 shuidi03 systemd[1]: Started MySQL Server.
[root@shuidi04 etc]# systemctl restart mysqld[root@shuidi04 etc]# systemctl status mysqld● mysqld.service - MySQL ServerLoaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)Active: active (running) since 一 2020-03-30 20:40:13 CST; 8s agoDocs: man:mysqld(8)Process: 8861 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)Process: 8839 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)Main PID: 8866 (mysqld)CGroup: /system.slice/mysqld.service└─8866 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
3月 30 20:40:12 shuidi04 systemd[1]: Starting MySQL Server...3月 30 20:40:13 shuidi04 systemd[1]: Started MySQL Server.
7. 在两台主机上建立账户并授权 slave
master1:
mysql> GRANT REPLICATION SLAVE ON *.* TO 'slave'@'%' IDENTIFIED BY 'Zan_666888';Query OK, 0 rows affected, 1 warning (0.00 sec)#查询Master1的状态mysql> show master status;+------------------+----------+--------------+-------------------------------------------------+-------------------+| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |+------------------+----------+--------------+-------------------------------------------------+-------------------+| mysql-bin.000002 | 435 | copydb2 | mysql,information_schema,performance_schema,sys | |+------------------+----------+--------------+-------------------------------------------------+-------------------+1 row in set (0.00 sec)
master2:
mysql> GRANT REPLICATION SLAVE ON *.* TO 'slave'@'%' IDENTIFIED BY 'Zan_666888';Query OK, 0 rows affected, 1 warning (0.01 sec)#查询Master2的状态mysql> show master status;+------------------+----------+--------------+-------------------------------------------------+-------------------+| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |+------------------+----------+--------------+-------------------------------------------------+-------------------+| mysql-bin.000001 | 435 | copydb2 | mysql,information_schema,performance_schema,sys | |+------------------+----------+--------------+-------------------------------------------------+-------------------+1 row in set (0.00 sec)
#分别记录下File和Position的值
#执行完此步骤后不要再操作主服务器MYSQL，防止主服务器状态值变化
8. 在从机上配置需要复制的主机
Slava1 复制 Master1，Slava2 复制 Master2
#复制主机的命令CHANGE MASTER TO MASTER_HOST='主机的IP地址',MASTER_USER='slave',MASTER_PASSWORD='123123',MASTER_LOG_FILE='mysql-bin.具体数字',MASTER_LOG_POS=具体值;
slave1:
CHANGE MASTER TO MASTER_HOST='172.16.94.131',MASTER_USER='slave',MASTER_PASSWORD='Zan_666888',MASTER_LOG_FILE='mysql-bin.000002',MASTER_LOG_POS=435;
slave2:
CHANGE MASTER TO MASTER_HOST='172.16.94.133',MASTER_USER='slave',MASTER_PASSWORD='Zan_666888',MASTER_LOG_FILE='mysql-bin.000001',MASTER_LOG_POS=435;
#启动两台从服务器复制功能
slave1:
mysql> start slave;#查看从服务器状态show slave status\G;
slave2:
mysql> start slave; #查看从服务器状态 show slave status\G;
#下面两个参数都是Yes，则说明主从配置成功！
# Slave_IO_Running: Yes
# Slave_SQL_Running: Yes
9. 两个主机互相复制
Master2 复制 Master1，Master1 复制 Master2
master2:
mysql> CHANGE MASTER TO MASTER_HOST='172.16.94.131',-> MASTER_USER='slave',-> MASTER_PASSWORD='Zan_666888',-> MASTER_LOG_FILE='mysql-bin.000002',MASTER_LOG_POS=435;Query OK, 0 rows affected, 2 warnings (0.02 sec)
mysql> start slave;Query OK, 0 rows affected (0.00 sec)
mysql> show slave status\G;
master1:
mysql> CHANGE MASTER TO MASTER_HOST='172.16.94.133',-> MASTER_USER='slave',-> MASTER_PASSWORD='Zan_666888',-> MASTER_LOG_FILE='mysql-bin.000001',MASTER_LOG_POS=435;Query OK, 0 rows affected, 2 warnings (0.02 sec)
mysql> start slave;Query OK, 0 rows affected (0.00 sec)
mysql> show slave status\G;
#下面两个参数都是Yes，则说明主从配置成功！
# Slave_IO_Running: Yes
# Slave_SQL_Running: Yes
10. Master1 主机新建库、新建表、insert 记录，Master2 和从机复制
mysql> CREATE DATABASE copydb2;Query OK, 1 row affected (0.00 sec)
mysql> show databases;+--------------------+| Database |+--------------------+| information_schema || copydb || copydb2 || mysql || nacos_config || performance_schema || seata || seata_account || seata_order || seata_storage || sys |+--------------------+11 rows in set (0.00 sec)
mysql> use copydb2;Database changedmysql> CREATE TABLE mytbl(id INT,NAME VARCHAR(20));Query OK, 0 rows affected (0.01 sec)
mysql> INSERT INTO mytbl VALUES(1,'zhang3');Query OK, 1 row affected (0.01 sec)
mysql> select * from mytbl;+------+--------+| id | NAME |+------+--------+| 1 | zhang3 |+------+--------+1 row in set (0.00 sec)
四个节点数据均实现了同步
11.如何停止从服务复制功能
stop slave;
如何重新配置主从
stop slave; reset master;
12.修改 Mycat 的配置文件 /usr/local/mycat/conf/schema.xml
修改<dataHost>的balance属性，通过此属性配置读写分离的类型
负载均衡类型，目前的取值有4 种：
（1）balance="0", 不开启读写分离机制，所有读操作都发送到当前可用的 writeHost 上。
（2）balance="1"，全部的 readHost 与 stand by writeHost 参与 select 语句的负载均衡，简单地说，当双主双从
模式(M1->S1，M2->S2，并且 M1 与 M2 互为主备)，正常情况下，M2,S1,S2 都参与 select 语句的负载均衡。
（3）balance="2"，所有读操作都随机的在 writeHost、readhost 上分发。
（4）balance="3"，所有读请求随机的分发到 readhost 执行，writerHost 不负担读压力
为了双主双从读写分离balance设置为1
<?xml version="1.0"?><!DOCTYPE mycat:schema SYSTEM "schema.dtd"><mycat:schema xmlns:mycat=";>
<schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100" dataNode="dn1">
</schema>
<dataNode name="dn1" dataHost="host1" database="copydb2" />
<dataHost name="host1" maxCon="1000" minCon="10" balance="1"writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100"><heartbeat>select user()</heartbeat>
<writeHost host="hostM1" url="172.16.94.131:3306" user="root"password="Zan_123456">
<readHost host="hostS1" url="172.16.94.132:3306" user="root" password="Zan_123456" /></writeHost>
<writeHost host="hostM2" url="172.16.94.133:3306" user="root"password="Zan_123456">
<readHost host="hostS2" url="172.16.94.134:3306" user="root" password="Zan_123456" /></writeHost>
</dataHost>
</mycat:schema>
#balance="1": 全部的readHost与stand by writeHost参与select语句的负载均衡。
#writeType="0": 所有写操作发送到配置的第一个writeHost，第一个挂了切到还生存的第二个
#writeType="1"，所有写操作都随机的发送到配置的 writeHost，1.5 以后废弃不推荐
#writeHost，重新启动后以切换后的为准，切换记录在配置文件中:dnindex.properties 。
#switchType="1": 1 默认值，自动切换。
# -1 表示不自动切换
# 2 基于 MySQL 主从同步的状态决定是否切换。
13.启动 Mycat,验证读写分离
[root@shuidi01 bin]# ./mycat stopStopping Mycat-server...Mycat-server was not running.[root@shuidi01 bin]# ./mycat startStarting Mycat-server...
#登录mycatmysql -umycat -pzan123456 -P 8066 -h 127.0.0.1#插入数据mysql> show databases;+----------+| DATABASE |+----------+| TESTDB |+----------+1 row in set (0.00 sec)
mysql> use TESTDB;Reading table information for completion of table and column namesYou can turn off this feature to get a quicker startup with -A
Database changedmysql> show tables;+-------------------+| Tables_in_copydb2 |+-------------------+| mytbl |+-------------------+1 row in set (0.00 sec)mysql> INSERT INTO mytbl VALUES(2,@@hostname);Query OK, 1 row affected, 1 warning (0.00 sec)
mysql> select * from mytbl;+------+----------+| id | NAME |+------+----------+| 1 | zhang3 || 2 | shuidi03 |+------+----------+2 rows in set (0.00 sec)
mysql> select * from mytbl;+------+----------+| id | NAME |+------+----------+| 1 | zhang3 || 2 | shuidi02 |+------+----------+2 rows in set (0.00 sec)mysql> select * from mytbl;+------+----------+| id | NAME |+------+----------+| 1 | zhang3 || 2 | shuidi04 |+------+----------+2 rows in set (0.00 sec)
#在Mycat里查询mytbl表,可以看到查询语句在Master2（shuidi03）、Slava1（shuidi02）、Slava2（shuidi04）主从三个主机间切换
14.抗风险能力
#停止数据库Master1
[root@shuidi01 logs]# systemctl stop mysqld[root@shuidi01 logs]# systemctl status mysqld● mysqld.service - MySQL ServerLoaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)Active: inactive (dead) since 一 2020-03-30 21:31:28 CST; 4s agoDocs: man:mysqld(8)Process: 9985 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)Process: 9946 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)Main PID: 9990 (code=exited, status=0/SUCCESS)
3月 30 20:38:22 shuidi01 systemd[1]: Starting MySQL Server...3月 30 20:38:23 shuidi01 systemd[1]: Started MySQL Server.3月 30 21:31:16 shuidi01 systemd[1]: Stopping MySQL Server...3月 30 21:31:28 shuidi01 systemd[1]: Stopped MySQL Server.
#在Mycat里插入数据依然成功，Master2自动切换为写主机
mysql> INSERT INTO mytbl VALUES(3,@@hostname);Query OK, 1 row affected, 1 warning (0.00 sec)mysql> select * from mytbl;+------+----------+| id | NAME |+------+----------+| 1 | zhang3 || 2 | shuidi04 || 3 | shuidi04 |+------+----------+3 rows in set (0.00 sec)
#启动数据库Master1
[root@shuidi01 logs]# systemctl start mysqld[root@shuidi01 logs]# systemctl status mysqld● mysqld.service - MySQL ServerLoaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)Active: active (running) since 一 2020-03-30 21:33:39 CST; 2s agoDocs: man:mysqld(8)Process: 3527 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)Process: 3473 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)Main PID: 3531 (mysqld)CGroup: /system.slice/mysqld.service└─3531 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
3月 30 21:33:38 shuidi01 systemd[1]: Starting MySQL Server...3月 30 21:33:39 shuidi01 systemd[1]: Started MySQL Server.
mysql> select * from mytbl;+------+----------+| id | NAME |+------+----------+| 1 | zhang3 || 2 | shuidi01 || 3 | shuidi01 |+------+----------+3 rows in set (0.00 sec)mysql> select * from mytbl;+------+----------+| id | NAME |+------+----------+| 1 | zhang3 || 2 | shuidi02 || 3 | shuidi02 |+------+----------+3 rows in set (0.00 sec)mysql> select * from mytbl;+------+----------+| id | NAME |+------+----------+| 1 | zhang3 || 2 | shuidi04 || 3 | shuidi04 |+------+----------+3 rows in set (0.00 sec)
#在Mycat里查询mytbl表,可以看到查询语句在Master1（shuidi01）、Slava1（shuidi02）、Slava2（shuidi04）
主从三个主机间切换
Master1、Master2 互做备机，负责写的主机宕机，备机切换负责写操作，保证数据库读写分离高
可用性。
标签： #mysql一从多主
