一、简介不管是Keepalived还是Heartbeat做高可用，虚拟主机，其高可用，都是站在服务器脚本去说的高可用，香港虚拟主机，而不是服务的角度。也就是说，香港服务器，如果服务器DOWN机或者网络出现故障，高可用是可以实现自动切换的。如果运行的服务，比如Nginx挂掉这些高可用软件是意识不到的，需要自己写脚本去实现服务的切换。二、安装配置Keepalived
复制内容到剪贴板代码:# ./configure# make# make install# cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/# cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/# cp /usr/local/sbin/keepalived /usr/bin/# chkconfig –add keepalived# mkdir /etc/keepalived/# cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/
编辑MASTER的主配置文件(MASTER: 1.1.1.1)
复制内容到剪贴板代码:# vim /etc/keepalived/keepalived.conf! Configuration File for keepalivedglobal_defs { router_id LVS_DEVEL}vrrp_script chk_nginx { script "/opt/monnginx.sh" interval 2 weight 2}vrrp_instance VI_1 { state MASTER interface eth0 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass mdnginx } virtual_ipaddress { 1.1.1.100 } track_script { chk_nginx}}
编辑BACKUP的主配置文件（BACKUP:1.1.1.2）
复制内容到剪贴板代码:# vim /etc/keepalived/keepalived.conf! Configuration File for keepalivedglobal_defs { router_id LVS_DEVEL}vrrp_script chk_nginx { script "/opt/monnginx.sh" interval 2 weight 2}vrrp_instance VI_1 { state BACKUP interface eth0 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass mdnginx } virtual_ipaddress { 1.1.1.100 } track_script { chk_nginx}}
三、启动服务与脚本编写（主机和备机都要执行）
复制内容到剪贴板代码:# service nginx start# service keepalived start
编写监控Nginx的脚本
复制内容到剪贴板代码:# vim /opt/monnginx.sh#!/bin/bash# author: honway.liu# date: 2013-03-15if [ $(ps -C nginx –no-header | wc -l) -eq 0 ]; then service nginx startfisleep 3if [ $(ps -C nginx –no-header | wc -l) -eq 0 ]; then service keepalived stopfi
改进脚本，加上报警功能。
复制内容到剪贴板代码:# vim /opt/monnginx.sh#!/bin/bash# author: honway.liu# date: 2013-03-15IPADDR=$(ip addr show eth0|awk ‘{print $2}’ | sed -n 3p)contact=(137XXXXXXXX@139.com)num=${#contact[@]}function email() {for ((i=0;i<num;i++));do echo "$IPADDR service problem" | mail -s "WARNING" ${contact[i]} — -f gm100861@gmail.comdone}if [ $(ps -C nginx –no-header | wc -l) -eq 0 ]; then service nginx startfiemailsleep 3if [ $(ps -C nginx –no-header | wc -l) -eq 0 ]; then service keepalived stopemailfi
这里的报警使用的是139邮箱，在139邮箱里面设置有邮件的时候，通知到手机，并且以长短信的方式。需要开户本机的sendmail服务。
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