Linux下安装Keepalived实现双机热备

其他开源框架

1、准备工作

Linux主机：10.122.1.35
Linux主机：10.122.1.36
虚拟IP:10.122.1.30

2、安装Keepalived

两台Linux主机都需要安装Keepalived

1、下载Keepalived

下载至目录：/home/zz/user/keepalived

wget http://keepalived.org/software/keepalived-1.3.8.tar.gz

2、解压Keepalived

tar -zxvf keepalived-1.3.8.tar.gz

3、安装Keepalived

./configure

此步骤如果出现错误：libnfnetlink 库找不到，则需要执行：

cp -R usr/ /

然后在当前目录

make
make install

4、配置防火墙

firewall-cmd --direct --permanent --add-rule ipv4 filter INPUT 0 \
--in-interface enp0s31f6 --destination 224.0.0.18 --protocol vrrp -j ACCEPT

---

firewall-cmd --direct --permanent --add-rule ipv4 filter OUTPUT 0 \
--out-interface enp0s31f6 --destination 224.0.0.18 --protocol vrrp -j ACCEPT

---

firewall-cmd --reload
注意：【enp0s31f6】为网卡名称。

5、配置服务启动

cp /home/zz/user/keepalived/keepalived-1.3.8/keepalived/etc/init.d/keepalived /etc/init.d/
mkdir /etc/keepalived
cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/

6、配置Keepalived

配置文件路径为：

/etc/keepalived/keepalived.conf

修改配置如下:

! Configuration File for keepalived
global_defs {
   notification_email {
    # acassen@firewall.loc
    # failover@firewall.loc
    # sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   # smtp_server 192.168.200.1
   # smtp_connect_timeout 30
   router_id SERVER_1
   vrrp_skip_check_adv_addr
   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}
vrrp_instance VI_1 {
    state MASTER
    interface enp0s25
    virtual_router_id 51
    priority 100
    protocol TCP
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        10.122.1.30/24
    }
}
virtual_server 10.122.1.30 3306 {
    delay_loop 2
    lb_algo wrr
    lb_kind DR
    nat_mask 255.255.255.0
    persistence_timeout 0
    protocol TCP
    real_server 10.122.1.35  3306 {
        weight 1
        MISC_CHECK {
            connect_timeout 60
            nb_get_retry 3
            delay_before_retry 3
            connect_port 3306
            misc_path "/home/zz/user/status_check/check_mysql.sh 10.122.1.35"
            misc_timeout 60
            misc_dynamic
        }
    }
    real_server 10.122.1.36 3306 {
        weight 1
        MISC_CHECK {
            connect_timeout 60
            nb_get_retry 3
            delay_before_retry 3
            connect_port 3306
            misc_path "/home/zz/user/status_check/check_mysql.sh 10.122.1.36"
            misc_timeout 60
            misc_dynamic
        }
    }
}

从机配置与主机配置大致一致，主要不同的配置项如下

router_id SERVER_2
state BACKUP
priority 50

7、编写心跳检查脚本

check_mysql.sh

#!/bin/bash
MYSQL_PING=`/usr/local/mysql/bin/mysqladmin -u root -h $1 ping`
MYSQL_OK="mysqld is alive"
if [[ ${MYSQL_PING} == ${MYSQL_OK} ]]; then
echo "yes"
exit 0
else
echo "no"
exit 1
fi

8、启动Keepalived

service keepalived start

查看日志：

tail -f /var/log/messages

9、判断是否脑裂

在主从服务器上都执行虚拟IP查看，如果虚拟IP都在自己身上，则发生了脑裂

ip addr|grep 10.122.1.30
发生脑裂主要原因为两台服务器之间无法进行心跳通讯，可检查防火墙或者进行串口通讯。