keepalived的安装及使用方法，用keepalived来实现网站的高可用

为了演示keepalived的安装及使用方法，这里我们准备了两台服务器，主服务器192.168.245.128和从服务器192.168.245.129，两台服务器都安装了keepalived，设置vip为192.168.245.222，当主服务器由故障时，vip自动漂移到从服务器上

一、安装keepalived

1.安装所需依赖

yum -y install vim wget gcc make tar openssl openssl-devel libnl libnl-devel libnfnetlink-devel

2.下载keepalived

wget https://www.keepalived.org/software/keepalived-2.2.4.tar.gz

3.解压

tar -zxf keepalived-2.2.4.tar.gz

4.进入解压后的目录

cd keepalived-2.2.4

5.编译

./configure --prefix=/usr/local/keepalived

6.安装

make && make install

二、keepalived配置

两台服务器都安装了keepalived后，我们分别对两台服务器进行配置

1.修改keepalived配置文件

vim /usr/local/keepalived/etc/keepalived/keepalived.conf

2.主服务器把默认的配置换成下面的配置

state是MASTER代表主服务器，BACKUP代表从服务器，priority是权重，权重高的优先占有vip，主服务器权重设置得比从服务器权重高一点，authentication是验证方式与从服务器保持一致即可，virtual_ipaddress就是vip，下面配置都不用改，只要把vip改成你自己的vip就可以

vrrp_instance VI_1 {
state MASTER
interface ens33
garp_master_delay 10
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.245.222
}
}

3.从服务器把默认的配置换成下面的配置

vrrp_instance VI_1 {
state BACKUP
interface ens33
garp_master_delay 10
smtp_alert
virtual_router_id 51
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.245.222
}
}

4.检查配置文件是否正确

执行下面这行命令，如果没有任何输出，说明配置文件没问题