Keepalived使用小结

编译安装

1、安装环境

CentOS release 6.4 Based on Linux 2.6.32，安装1.2.9，没问题

在Red Hat Enterprise Linux Server release 5.3 (Tikanga) Based on 2.6.18 安装1.2.9，有问题，1.2.8没问题

2、获取源码

http://www.keepalived.org/software/keepalived-1.2.9.tar.gz

http://www.keepalived.org/software/keepalived-1.2.8.tar.gz

3、编译

tar -xvf keepalived-1.2.x.tar.gz

mkdir /opt/keepalived

cd keepalived-1.2.x

./configure --prefix=/opt/keepalived

make 

make install

4、配置

 假设有两台机器A,B

A的keepalived.conf配置：

global_defs {
   router_id LVS_DEVEL_TEST
}
vrrp_script Monitor_Haroxy {
# script "/home/plat/ott_release/script/haproxy_keepalived.sh"
 script "killall -0 haproxy"
 interval 3
 weight -20
}
vrrp_instance VI_HA {
    state BACKUP
    interface em1 #网卡接口
    virtual_router_id 53
    priority 90
    advert_int 1
    nopreempt
    authentication {
        auth_type PASS
        auth_pass 1111
}
        #notify_master /home/plat/ ott_release/script/redis_master.sh
        #notify_backup/home/plat/ott_release/script/redis_backup.sh
   track_script {
        Monitor_Haproxy
    }
    virtual_ipaddress {
        10.0.63.237
    }
}

B的keepalived.conf配置：

global_defs {
   router_id LVS_DEVEL_TEST
}
vrrp_script Monitor_Haroxy {
 script "/home/plat/ott_release/script/haproxy_keepalived.sh"
 #script "killall -0 haproxy"
 interval 3
 weight -20
}
vrrp_instance VI_HA {
    state BACKUP
    interface br-ex
    virtual_router_id 53
    priority 80
    advert_int 1
    nopreempt
    authentication {
        auth_type PASS
        auth_pass 1111
}
notify_master /home/plat/ ott_release/script/redis_master.sh
    notify_backup/home/plat/ott_release/script/redis_backup.sh
   track_script {
        Monitor_Haproxy
    }
    virtual_ipaddress {
        10.0.63.237
    }
}

 以下配置，A、B是相同的

/home/plat/ott_release/script/haproxy_keepalived.sh示例如下：

#!/bin/bash

count = `ps aux | grep -v grep | grep haproxy | wc -l`

if [ $count > 0 ]; then

exit 0

else

exit 1

fi

注：

keepalived会定时执行脚本并对脚本执行的结果进行分析，动态调整vrrp_instance的优先级。

• 如果脚本执行结果为0，并且weight配置的值大于0，则优先级相应的增加

• 如果脚本执行结果非0，并且weight配置的值小于0，则优先级相应的减少

• 其他情况，维持原本配置的优先级，即配置文件中priority对应的值。

说明几点：

1）优先级不会不断的提高或者降低

2）可以编写多个检测脚本并为每个检测脚本设置不同的weight

3）不管提高优先级还是降低优先级，最终优先级的范围是在[1,254]，不会出现优先级小于等于0或者优先级大于等于255的情况

说明一种情况，以上配置的两台机器，启动后A weight高，所以变成Master，如果Master检测到进程出问题，将自身weight减少20即60，小于备机，所以备机切换为Master；当原Master即A恢复，由于其weight为80，会抢占B成为Master。

启动时，在安装目录下运行：./sbin/keepalived -f conf/keepalived.conf -c run/checker.pid -r run/vrrp.pid -p run/pid.pid

运行两个keepalived进程时，例如：./sbin/keepalived -f conf/keepalived1.conf -c run/checker1.pid -r run/vrrp1.pid -p run/pid1.pid