centos7下 Mysql+Keepalived 双主热备高可用图文配置详解

环境描述：
Centos7 版本Master1：192.168.1.146        安装mysql和keepalivedMaster2: 192.168.1.14
7        安装mysql和keepalivedVIP：192.168.1.188

要实现主主同步，可以先实现主从同步，即master1->master2的主从同步，然后master2->master1的主从同步.这样，双方就完成了主主同步。
 注意下面几点：1）要保证同步服务期间之间的网络联通。即能相互ping通，能使用对方授权信息连接到对方数据库（防火墙开放3306端口）。2）关闭selinux。
3）同步前，双方数据库中需要同步的数据要保持一致。这样，同步环境实现后，再次更新的数据就会如期同步了。
这里略过。

配置Mysql+Keepalived故障转移的高可用环境   


1）安装keepalived并将其配置成系统服务。master1和master2两台机器上同样进行如下操作：
[root@master1 ~]# yum install -y openssl-devel popt-devel[root@master1 ~]# cd
/usr/local/src/[root@master1 src]# wget
http://www.keepalived.org/software/keepalived-1.3.5.tar.gz[root@master1 src]#
tar -zvxf keepalived-1.3.5.tar.gz[root@master1 src]# cd keepalived-1.3.5
[root@master1 keepalived-1.3.5]# ./configure --prefix=/usr/local/keepalived
[root@master1 keepalived-1.3.5]# make && make install     [root@master1
keepalived-1.3.5]# cp
/usr/local/src/keepalived-1.3.5/keepalived/etc/init.d/keepalived
/etc/rc.d/init.d/[root@master1 keepalived-1.3.5]# cp
/usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/[root@master1
keepalived-1.3.5]# mkdir /etc/keepalived/[root@master1 keepalived-1.3.5]# cp
/usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
[root@master1 keepalived-1.3.5]# cp /usr/local/keepalived/sbin/keepalived
/usr/sbin/[root@master1 keepalived-1.3.5]# echo "/etc/init.d/keepalived start"
>> /etc/rc.local     
2）master1机器上的keepalived.conf配置。（下面配置中没有使用lvs的负载均衡功能，所以不需要配置虚拟服务器virtual server）
[root@master1 ~]# cp /etc/keepalived/keepalived.conf
/etc/keepalived/keepalived.conf.bak[root@master1 ~]# vim
/etc/keepalived/keepalived.conf       ＃清空默认内容，直接采用下面配置：! Configuration File for
keepalived global_defs { router_id MASTER-HA } vrrp_script chk_mysql_port {
script "/etc/keepalived/chk_mysql.sh" interval 2 weight -5 fall 2 rise 1 }
vrrp_instance VI_1 { state MASTER interface ens33 mcast_src_ip 192.168.1.146
virtual_router_id 51 priority 101 advert_int 1 authentication { auth_type PASS
auth_pass 1111 } virtual_ipaddress { 192.168.1.188 } track_script {
chk_mysql_port } virtual_server 192.168.1.188 3306 { delay_loop 6 lb_algo wrr
lb_kind DR #nat_mask 255.255.255.0 persistence_timeout 50 protocol TCP ## Real
Server设置，3306就是连接端口 real_server 192.168.1.146 3306 { weight 3 ##权重 TCP_CHECK {
connect_timeout 3 nb_get_retry 3 delay_before_retry 3 connect_port 3306 } }
real_server 192.168.1.147 3306 { weight 3 TCP_CHECK { connect_timeout 3
nb_get_retry 3 delay_before_retry 3 connect_port 3306 } } } }


master2机器上的keepalived配置。master2机器上的keepalived.conf文件只修改priority为90、nopreempt不设置、real_server设置本地IP。
! Configuration File for keepalived global_defs { router_id BACKUP-HA }
vrrp_script chk_mysql_port { script "/etc/keepalived/chk_mysql.sh" interval 2
weight -5 fall 2 rise 1 } vrrp_instance VI_1 { state BACKUP interface ens33
mcast_src_ip 192.168.1.147 virtual_router_id 51 priority 99 advert_int 1
authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress {
192.168.1.188 } track_script { chk_mysql_port } virtual_server 192.168.1.188
3306 { delay_loop 6 #服务轮询的时间间隔 lb_algo wrr #加权轮询调度，LVS调度算法
rr|wrr|lc|wlc|lblc|sh|sh lb_kind DR #LVS集群模式
NAT|DR|TUN，其中DR模式要求负载均衡器网卡必须有一块与物理网卡在同一个网段 #nat_mask 255.255.255.0
persistence_timeout 50 #会话保持时间 protocol TCP #健康检查协议 ## Real Server设置，3306就是连接端口
real_server 192.168.1.146 3306 { weight 3 ##权重 TCP_CHECK { connect_timeout 3
nb_get_retry 3 delay_before_retry 3 connect_port 3306 } } real_server
192.168.1.147 3306 { weight 3 TCP_CHECK { connect_timeout 3 nb_get_retry 3
delay_before_retry 3 connect_port 3306 } } } }

编写切换脚本。KeepAlived做心跳检测，如果Master的MySQL服务挂了(3306端口挂了),那么它就会选择自杀。Slave的KeepAlived通过心跳检测发现这个情况，

就会将VIP的请求接管

[root@master1 ~]# vim /etc/keepalived/chk_mysql.sh
#!/bin/bashcounter=$(netstat -na|grep "LISTEN"|grep "3306"|wc -l)if [ 
"${counter}" -eq 0 ]; then    /etc/init.d/keepalived stopfi 
[root@master1 ~]# chmod 755 /etc/keepalived/chk_mysql.sh     
启动keepalived服务[root@master1 ~]# /etc/init.d/keepalived start正在启动
keepalived：                                      [确定]
在启动的时候有可能启动失败   打开 vim /lib/systemd/system/keepalived.service  在第7行

PIDFile
=/usr/local/program/keepalived/var/run/keepalived.pid      ##发现这个目录不存在，无法写入keepalived.pid  
修改成 PIDFile=/var/run/keepalived.pid 执行
 systemctl daemon-reload    #重新载入 systemd，扫描新的或有变动的单元  在运行就Ok了    
/etc/init.d/keepalived start



ip addr 可以看到 vip在master上



三、测试 

最简单的测试

mysql -h192.168.1.188 -uroot1 -proot1


show databases;




在147服务上看 ip addr 也可以看到vip漂移到了147服务上




/******************/


上面那个脚本简单且粗暴，即脚本一旦监测到Master的mysql服务关闭，就立刻把keepalived服务关闭，不能实现vip转移，也就是当Master数据库恢复的是时候不能再切回来！

下面这个脚本可以实现 当监测到Master的mysql服务关闭后，就会将vip切换到Backup上 
当Master的mysql服务恢复后，就会再次将VIP资源切回来
#!/bin/bashMYSQL=/usr/local/mysql/bin/mysqlMYSQL_HOST=localhostMYSQL_USER=root
MYSQL_PASSWORD=123456CHECK_TIME=3  #mysql  is working MYSQL_OK is 1 , mysql
down MYSQL_OK is 0  MYSQL_OK=1  function check_mysql_helth (){    $MYSQL -h
$MYSQL_HOST -u $MYSQL_USER -p${MYSQL_PASSWORD} -e "show status;" >/dev/null 2>&1
    if [ $? = 0 ] ;then    MYSQL_OK=1    else    MYSQL_OK=0    fi    return 
$MYSQL_OK}while [ $CHECK_TIME -ne 0 ]do    let "CHECK_TIME -= 1"    
check_mysql_helthif [ $MYSQL_OK = 1 ] ; then    CHECK_TIME=0    exit 0fiif [
$MYSQL_OK -eq 0 ] &&  [ $CHECK_TIME -eq 0 ]then    pkill keepalived    exit 1fi
sleep 1done

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