Keepalived使用小结

zhouli

　　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