linux下安装keepalived实现mysql主主高可用

安装keepalived与mysql主主高可用
前提：已搭建mysql主主
环境：Centos7.3
IP1：10.10.133.117（主：master-jin）
IP2：10.10.133.118（从主：node1-jin）
VIP：10.10.133.129

1、两台机器上同样进行如下操作：
yum install -y wget curl gcc openssl-devel libnl3-devel net-snmp-devel
cd /opt/app/
wget https://www.keepalived.org/software/keepalived-2.0.1.tar.gz
tar -zxvf keepalived-2.0.1.tar.gz
cd keepalived-2.0.1/
./configure --prefix=/opt/app/keepalived

如果报configure: error: libnfnetlink headers missing

上传libnfnetlink-devel-1.0.1-13.el8.x86_64.rpm
执行 rpm -ivh libnfnetlink-devel-1.0.1-13.el8.x86_64.rpm --nodeps
再次编译：./configure --prefix=/opt/app/keepalived
make && make install
cp /opt/app/keepalived-2.0.1/keepalived/etc/init.d/keepalived /etc/rc.d/init.d/
cp /opt/app/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
cp /opt/app/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
mkdir /etc/keepalived/
cp /opt/app/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
cp /opt/app/keepalived/sbin/keepalived /usr/sbin/
echo "/etc/init.d/keepalived start" >> /etc/rc.local

2、master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）
cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
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 {
notp_server mail.umfintech.com
smtp_connect_timeout 30
router_id master-jin ## 标识本节点的字条串，通常为 hostname
}

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 "/home/umpay/UMSdata/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 3 #检测连续3次失败才算确定是真失败。会用weight减少优先级（1-255之间）
rise 2 #检测2次成功就算成功。但不修改优先级
}

vrrp_instance VI_1 {
state MASTER
interface ens33 #指定虚拟ip的网卡接口,根据网卡名称更改
mcast_src_ip 10.10.133.117
virtual_router_id 51 #路由器标识，MASTER和BACKUP必须是一致的
priority 100 #定义优先级，数字越大，优先级越高，在同一个vrrp_instance下，MASTER的优先级必须大于BACKUP的优先级。这样MASTER故障恢复后，就可以将VIP资源再次抢回来
advert_int 1 # 组播信息发送间隔，两个节点设置必须一样，默认 1s
#nopreempt #非抢占模式，开启需所有节点配置为BACKUP，根据priority大小进行匹配主备
authentication { # 设置验证信息，两个节点必须一致
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.10.133.129 #虚拟 ip，两个节点必须一致，可以定义多个，每行一个
}

track_script { # 检查 mysql 服务是否存活
chk_mysql_port
}
}
3、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

vim /home/umpay/UMSdata/chk_mysql.sh

!/bin/bash

A=ps -C mysqld --no-header |wc -l
if [ $A -eq 0 ]; then
systemctl restart mysql
sleep 10
B=ps -C mysqld --no-header |wc -l
if [ $B -eq 0 ]; then
killall keepalived
fi
fi
chmod 755 /home/umpay/UMSdata/chk_mysql.sh

启动keepalived服务

/etc/init.d/keepalived start
4、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、mcast_src_ip设置本地IP。
cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
! Configuration File for keepalived

global_defs {
notp_server mail.umfintech.com
smtp_connect_timeout 30
router_id node1-jin
}

vrrp_script chk_mysql_port {
script "/home/umpay/UMSdata/chk_mysql.sh"
interval 2
weight -5
fall 3
rise 2
}

vrrp_instance VI_1 {
state BACKUP
interface ens33
mcast_src_ip 10.10.133.118
virtual_router_id 51
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.10.133.129
}

track_script {
chk_mysql_port
}
}

chmod 755 /home/umpay/UMSdata/chk_mysql.sh
/etc/init.d/keepalived start

5、#查看启动日志
tail -f /var/log/messages

6、#测试验证
1、ip a 查看主（master-jin）是否生成VRRP虚拟IP 133.29；
2、停止主（master-jin）上的mysql，然后查看mysql是否会被自动拉起；
3、killall keepalived 停止主（master-jin）上的keepalived，然后ip a查看备（node1-jin）是否生成VRRP虚拟IP 133.29。