MySQL互为主备（双主）加keepalived实现故障自动转换
MySQL双主（互为主从）
环境：
| 主机名 | 系统环境 | 软件 | IP |
|---|---|---|---|
| DB1 | CentOS7.6 | MySQL5.7 ，keepalived | 192.168.66.63 |
| DB2 | CentOS7.6 | MySQL5.7 ，keepalived | 192.168.66.64 |
| Client | CentOS7.6 | MySQL5.7 | 192.168.66.61 |
| VIP | 192.168.66.200 |
一，实现MySQL主主同步
DB1、DB2都已安装MySQL，安装过程省略
MySQL安装见之前的文章：MySQL安装
1，修改MySQL配置文件
在/etc/my.ccnf文件中的[mysqld]段加配置信息
DB1:
[root@DB1 ~]# vim /etc/my.cnf
#mysql双主增加信息
#节点标识，每台的server—id不能一样，全局唯一
server-id=1
#开启binlg日志，用于主从数据复制
log-bin=mysql-bin
#开启relay-log日志
relay-log=mysql-relay-bin
#复制过滤选项
replicate-wild-ignore-table=mysql.%
replicate-wild-ignore-table=test.%
replicate-wild-ignore-table=information_schema.%
#字段一次递增多少
auto-increment-increment = 2
#自增字段的起始值：1、3、5、7、等奇数
auto-increment-offset = 1
slave-skip-errors = all
#保存配置，重启MySQL服务
[root@DB1 ~]# service mysqld restart
Shutting down MySQL.... SUCCESS!
Starting MySQL. SUCCESS!
DB2：
[root@dg ~]# vim /etc/my.cnf
#mysql双主新增内容
server-id=2
log-bin=mysql-bin
relay-log=mysql-relay-bin
replicate-wild-ignore-table=mysql.%
replicate-wild-ignore-table=test.%
replicate-wild-ignore-table=information_schema.%
auto-increment-increment = 2
auto-increment-offset = 2
slave-skip-errors = all
#保存配置，重启服务
[root@dg ~]# service mysqld restart
Shutting down MySQL.... SUCCESS!
Starting MySQL. SUCCESS!
2，配置DB1、DB2主主模式
2.1，查看log bin日志和pos位置
DB1:
[root@DB1 ~]# mysql -u root -p
Enter password:
mysql> show master status;
DB2:
[root@dg ~]# mysql -uroot -p
Enter password:
mysql> show master status;
2.2,DB1、DB2互相提升访问权限
DB1:
#创建DB2的复制用户并授权
mysql> grant replication slave on *.* to 'cproot'@'192.168.66.64' identified by 'cp123456';
Query OK, 0 rows affected, 1 warning (0.03 sec)
#刷新并查看log bin日志和pos位置
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)
mysql> show master status;
DB2:
mysql> grant replication slave on *.* to 'cproot'@'192.168.66.63'identified by 'cp123456';
Query OK, 0 rows affected, 1 warning (0.02 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)
mysql> show master status;
2.3，将对方都设置成自己的主服务器
注意：master_log_file和master_log_pos是对方服务器最新的数据
DB1:
mysql> change master to master_host='192.168.66.64',master_user='cproot',master_password='cp123456',master_log_file='mysql-bin.000001',master_log_pos=605;
Query OK, 0 rows affected, 2 warnings (0.20 sec)
DB2：
mysql> change master to master_host='192.168.66.63',master_user='cproot',master_password='cpp123456',master_log_file='mysql-bin.000001',master_log_pos=605;
Query OK, 0 rows affected, 2 warnings (0.17 sec)
2.4，查看DB1,DB2服务器状态
DB1:
mysql> start slave;
Query OK, 0 rows affected (0.01 sec)
mysql> show slave status\G;
DB2:
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
mysql> show slave status\G;
这两个地方都为yes说明主主同步成功，如果不是yes的话有以下几种排查思路：
1，网络不通
2，密码不正确
3，pos不对
4，防火墙没关
3，测试主主同步
在DB1服务器上新建数据库one，然后在DB2上查看是否同步
DB2删除one，查看DB1是否还存在
DB1:
mysql> create database one;
Query OK, 1 row affected (0.02 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| one |
| performance_schema |
| sys |
+--------------------+
5 rows in set (0.00 sec)
DB2:
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| one |
| performance_schema |
| sys |
+--------------------+
5 rows in set (0.01 sec)
#DB2删除此数据库看DB1是否同步
mysql> drop database one;
Query OK, 0 rows affected (0.01 sec)
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
DB1:
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
双向操作没问题，主主同步成功
二，使用keepalived实现故障自动转移
1，安装keepalived
keepalived下载
http://www.keepalived.org/software/keepalived-1.3.5.tar.gz
DB1、DB2:
[root@DB1 ~]# yum -y install openssl-devel
[root@DB1 ~]# yum -y install libnl libnl-devel libnfnetlink-devel openssl-devel
[root@DB1 ~]# cd /usr/local/src/
#上传keepalived软件包
[root@DB1 src]# ll | grep keepalived-1.3.5.tar.gz
-rw-r--r--. 1 root root 683183 Jul 9 10:22 keepalived-1.3.5.tar.gz
[root@DB1 src]# tar -zxf keepalived-1.3.5.tar.gz
[root@DB1 src]# cd keepalived-1.3.5
[root@DB1 keepalived-1.3.5]# ./configure --prefix=/usr/local/keepalived
[root@DB1 keepalived-1.3.5]# make && make install
如果有如下报错：
1，
Error: Package: libnl-devel-1.1.4-3.el7.x86_64 (base)
Requires: kernel-headers
#解决方法：
#注释掉exclude=kernel*
[root@DB2 ~]# vim /etc/yum.conf
#exclude=kernel*
2，
configure: error: in `/usr/local/src/keepalived-1.3.5':
configure: error: no acceptable C compiler found in $PATH
See `config.log' for more details
#解决放法
[root@DB2 keepalived-1.3.5]# yum install gcc gcc-c++ gcc-g77
2，将keepalived配置成系统服务
DB1,DB2:
[root@DB1 keepalived-1.3.5]# cp /usr/local/src/keepalived-1.3.5/keepalived/etc/init.d/keepalived /etc/rc.d/init.d/
[root@DB1 keepalived-1.3.5]# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
[root@DB1 keepalived-1.3.5]# mkdir -p /etc/keepalived/
[root@DB1 keepalived-1.3.5]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
[root@DB1 keepalived-1.3.5]# ln -s /usr/local/keepalived/sbin/keepalived /usr/sbin/
[root@DB1 keepalived-1.3.5]# echo "/etc/init.d/keepalived start" >>/etc/rc.local
3，修改配置文件
DB1:
[root@DB1 ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
[root@DB1 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
[email protected]
[email protected]
[email protected]
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id MASTER-HA
}
#检测脚本
vrrp_script chk_mysql_port { #检测mysql服务是否在运行。有很多方式，比如进程，用脚本检测等等
script "/opt/chk_mysql.sh" #这里通过脚本监测
interval 2 #脚本执行间隔，每2s检测一次
weight -5 #脚本结果导致的优先级变更，检测失败（脚本返回非0）则优先级 -5
fall 2 #检测连续2次失败才算确定是真失败。会用weight减少优先级（1-255之间）
rise 1 #检测1次成功就算成功。但不修改优先级
}
vrrp_instance VI_1 {
state BACKUP #MATER或BAKUP，因为是主主所以此处配置为BACKUP,两台节点一样
interface ens160 #指定虚拟ip的网卡接口
mcast_src_ip 192.168.66.63
virtual_router_id 51 #路由器标识,两台节点一致
priority 100 #优先级,数字越大优先级越高
advert_int 1
authentication {
auth_type PASS #认证类型
auth_pass 1111 #认证密码,两节点一致
}
virtual_ipaddress { #虚拟ip,飘移地址
192.168.66.200
}
track_script {
chk_mysql_port
}
}
编辑切换脚本，keepalived做心跳检测，如果master的MySQL服务挂了（3306端口宕了），那么就会选择“自杀”。slave的keepalived通过心跳检测发现这个情况就会将VIP飘移地址请求接管
[root@DB1 ~]# yum -y install net-tools
[root@DB1 ~]# vim /opt/chk_mysql.sh
#!/bin/bash
counter=$(netstat -na|grep "LISTEN"|grep "3306"|wc -l)
if [ "${counter}" -eq 0 ]; then
/etc/init.d/keepalived stop
fi
[root@DB1 ~]# chmod 755 /opt/chk_mysql.sh
[root@DB1 sbin]# /etc/init.d/keepalived start
我这里启动是失败了原因是在keepalived.service文件中pid文件路径不存在
[root@DB1 sbin]# vim /lib/systemd/system/keepalived.service
#把原来的注释下面的重新写上
#PIDFile=/usr/local/keepalived/var/run/keepalived.pid
PIDFile=/var/run/keepalived.pid
#重新加载单元然后重启
root@DB1 sbin]# systemctl daemon-reload
[root@DB1 sbin]# /etc/init.d/keepalived start
Starting keepalived (via systemctl): [ OK ]
查看虚拟ip是否已经有了
[root@DB1 sbin]# ip addr
2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 00:50:56:98:01:f9 brd ff:ff:ff:ff:ff:ff
inet 192.168.66.63/24 brd 192.168.66.255 scope global noprefixroute ens160
valid_lft forever preferred_lft forever
inet 192.168.66.200/32 scope global ens160
valid_lft forever preferred_lft forever
DB2:
[root@DB2 ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
[root@DB2 ~]# >/etc/keepalived/keepalived.conf
#DB2的配置文件夹只修改IP地址和优先级，优先级比DB1低
[root@DB2 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
[email protected]
[email protected]
[email protected]
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id MASTER-HA
}
vrrp_script chk_mysql_port {
script "/opt/chk_mysql.sh"
interval 2
weight -5
fall 2
rise 1
}
vrrp_instance VI_1 {
state BACKUP
interface ens160
mcast_src_ip 192.168.66.64
virtual_router_id 51
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.66.200
}
track_script {
chk_mysql_port
}
}
[root@DB2 ~]# yum -y install net-tools
[root@DB2 ~]# vim /opt/chk_mysql.sh
#!/bin/bash
counter=$(netstat -na|grep "LISTEN"|grep "3306"|wc -l)
if [ "${counter}" -eq 0 ]; then
/etc/init.d/keepalived stop
fi
[root@DB2 ~]# chmod 755 /opt/chk_mysql.sh
[root@DB2 ~]# vim /lib/systemd/system/keepalived.service
#PIDFile=/usr/local/keepalived/var/run/keepalived.pid
PIDFile=/var/run/keepalived.pid
[root@DB2 ~]# systemctl daemon-reload
[root@DB2 ~]# /etc/init.d/keepalived start
Starting keepalived (via systemctl): [ OK ]
配置参数说明：
（1）notification_email：收件箱
（2）notification_email_from：发件箱
（3）vrrp_mcast_group4：VRRP多播地址，必须为D类地址，即可用IP范围为224.0.0.0~239.255.255.255
（4）script：自定义检查脚本路径
（5）interval：自定义检查脚本的执行时间间隔，单位为秒
（6）vrrp_instance：配置虚拟路由器实例
（7）state：MASTER或BACKUP，当前节点在此虚拟路由器上的初始状态，只能有一个为MASTER，其余的都应该为BACKUP，此处都需要配置为BACKUP
（8）nopreempt：定义工作模式为非抢占模式，默认为抢占模式
（9）preempt_delay：抢占模式下，节点上线后触发新选举操作的延迟时长，单位为秒
（10）interface：绑定当前虚拟路由器使用的物理接口
（11）virtual_router_id：当前虚拟路由器的唯一标识，取值范围为0~255，两个节点必须一致
（12）priority：当前主机在此虚拟路由器中的优先级，取值范围为0~255
（13）advert_int：VRRP通告心跳信息和优先级信息的时间间隔，单位为秒
（14）auth_type：认证类型
（15）auth_pass：认证密码，两个节点必须一致
（16）virtual_ipaddress：VIP地址
（17）可通过命令# man keepalived.conf查看keepalived.conf配置文件的详细帮助文档
4，查看VIP
目前vip在DB1身上，因为DB1优先级较高
DB1:
DB2：
5，测试
5.1，测试vip能不能正常切换
DB1:
#关闭MySQL，看vip是否还在
[root@DB1 ~]# /etc/init.d/mysqld stop
Shutting down MySQL............ SUCCESS!
[root@DB1 ~]# ps -ef| grep keepalived
root 11124 3959 0 14:36 pts/3 00:00:00 grep --color=auto keepalived
[root@DB1 ~]# ip addr
DB2：
[root@DB2 ~]# ip addr
关闭DB1的MySQL服务keepalived服务也自动关闭了，vip成功到DB2服务器上
启动DB1的MySQL服务看能不能正常飘回
注意：DB1要先启动MySQL在启动keepalived，不然先启动keepalived的话脚本检测不到MySQL会立马关闭的
DB1:
[root@DB1 ~]# service mysqld satrt
Usage: mysqld {start|stop|restart|reload|force-reload|status} [ MySQL server options ]
[root@DB1 ~]# service mysqld start
Starting MySQL. SUCCESS!
[root@DB1 ~]# service keepalived start
Starting keepalived (via systemctl): [ OK ]
[root@DB1 ~]# ip addr
DB2:
经测试，DB1MySQL服务关闭vip服务自动到DB2上，DB1恢复后，vip地址自动飘回
6，故障转移高可用测试
6.1，授权客户端
通过客户端登录写入数据测试
首先要在DB1和DB2服务器上授权允许用户远程登录，并设置防火墙规则
DB1:
#用户授权
[root@DB1 ~]# mysql -u root -p
Enter password:
mysql> grant all on *.* to root@'192.168.66.%' identified by "123456";
Query OK, 0 rows affected, 1 warning (0.02 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.05 sec)
#添加防火墙规则
#因为Centos7里面没有iptables这个文件所以需要先安装
[root@DB1 ~]# yum -y install iptables iptables-services
[root@DB1 ~]# vim /etc/sysconfig/iptables
#允许组播地址通信
-A INPUT -s 192.168.0.0/24 -d 224.0.0.18 -j ACCEPT
#允许VRRP通信
-A INPUT -s 192.168.0.0/24 -p vrrp -j ACCEPT
#开放mysql的3306端口
-A INPUT -m state --state NEW -m tcp -p tcp --dport 3306 -j ACCEPT
[root@DB1 ~]# systemctl start iptables
DB2:
[root@DB2 ~]# mysql -uroot -p
Enter password:
mysql> grant all on *.* to root@'192.168.66.%' identified by "123456";
Query OK, 0 rows affected, 1 warning (0.01 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.02 sec)
[root@DB2 ~]# yum -y install iptables iptables-services
[root@DB2 ~]# vim /etc/sysconfig/iptables
-A INPUT -s 192.168.0.0/24 -d 224.0.0.18 -j ACCEPT
-A INPUT -s 192.168.0.0/24 -p vrrp -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 3306 -j ACCEPT
[root@DB2 ~]# systemctl start iptables
6.2，数据测试
客户端通过vip连接MySQL服务器，看是否能成功
Client:
[root@Client ~]# mysql -h 192.168.66.200 -uroot -p123456
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 5.7.24-log MySQL Community Server (GPL)
Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
#查看当前vip在哪一台服务器上
mysql> show variables like "%hostname%";
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| hostname | DB1 |
+---------------+-------+
1 row in set (0.00 sec)
创建数据库，然后在库中创建一张表，并插入数据
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
mysql> create database one;
Query OK, 1 row affected (0.02 sec)
mysql> use one;
Database changed
mysql> create table test_table(id int,name varchar(32));
Query OK, 0 rows affected (0.18 sec)
mysql> show tables;
+---------------+
| Tables_in_one |
+---------------+
| test_table |
+---------------+
1 row in set (0.00 sec)
mysql> insert into test_table(id,name) values(1,'glt');
Query OK, 1 row affected (0.03 sec)
mysql> select * from test_table;
+------+------+
| id | name |
+------+------+
| 1 | glt |
+------+------+
1 row in set (0.00 sec)
验证数据：
DB1:
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| one |
| performance_schema |
| sys |
+--------------------+
5 rows in set (0.00 sec)
mysql> use one;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+---------------+
| Tables_in_one |
+---------------+
| test_table |
+---------------+
1 row in set (0.00 sec)
mysql> select * from test_table;
+------+------+
| id | name |
+------+------+
| 1 | glt |
+------+------+
1 row in set (0.00 sec)
DB2：
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| one |
| performance_schema |
| sys |
+--------------------+
5 rows in set (0.04 sec)
mysql> use one;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+---------------+
| Tables_in_one |
+---------------+
| test_table |
+---------------+
1 row in set (0.00 sec)
mysql> select * from test_table;
+------+------+
| id | name |
+------+------+
| 1 | glt |
+------+------+
1 row in set (0.00 sec)
6.3，故障测试
停止DB1的MySQL服务，在客户端通过vip登录查看当前在哪一台服务器上并继续在创建的表中插入数据，然后重启DB1看是否可以同步数据。
DB1:
[root@DB1 ~]# service mysqld stop
Shutting down MySQL............ SUCCESS!
Client:
[root@Client ~]# mysql -h 192.168.66.200 -uroot -p123456
mysql> show variables like "%hostname%";
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| hostname | DB2 |
+---------------+-------+
1 row in set (0.01 sec)
mysql> use one;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+---------------+
| Tables_in_one |
+---------------+
| test_table |
+---------------+
1 row in set (0.01 sec)
mysql> insert into test_table(id,name)values(2,'hh');
Query OK, 1 row affected (0.04 sec)
mysql> select * from test_table;
+------+------+
| id | name |
+------+------+
| 1 | glt |
| 2 | hh |
+------+------+
2 rows in set (0.00 sec)
查看同步情况：
DB2:
mysql> select * from test_table;
+------+------+
| id | name |
+------+------+
| 1 | glt |
| 2 | hh |
+------+------+
2 rows in set (0.00 sec)
DB1:
[root@DB1 ~]# service mysqld start
Starting MySQL. SUCCESS!
[root@DB1 ~]# mysql -uroot -p123456
mysql> use one;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+---------------+
| Tables_in_one |
+---------------+
| test_table |
+---------------+
1 row in set (0.00 sec)
mysql> select * from test_table;
+------+------+
| id | name |
+------+------+
| 1 | glt |
| 2 | hh |
+------+------+
2 rows in set (0.00 sec)
|
±-----±-----+
2 rows in set (0.00 sec)
查看同步情况：
DB2:
~~~MySQL
mysql> select * from test_table;
+------+------+
| id | name |
+------+------+
| 1 | glt |
| 2 | hh |
+------+------+
2 rows in set (0.00 sec)
DB1:
[root@DB1 ~]# service mysqld start
Starting MySQL. SUCCESS!
[root@DB1 ~]# mysql -uroot -p123456
mysql> use one;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+---------------+
| Tables_in_one |
+---------------+
| test_table |
+---------------+
1 row in set (0.00 sec)
mysql> select * from test_table;
+------+------+
| id | name |
+------+------+
| 1 | glt |
| 2 | hh |
+------+------+
2 rows in set (0.00 sec)
数据同步成功！