一、拓扑环境: 主nginx负载均衡器 192.168.166.203 辅nginx负载均衡器 192.168.166.177 VIP地址 192.168.166.178
make && make install cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/ cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/ cp /usr/local/keepalived/sbin/keepalived /bin/ chkconfig --add keepalived chmod 755 /etc/init.d/keepalived chkconfig keepalived on service keepalived start
二.修改配置文件为以下内容: [master slave] MASTER vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email_from xxx@xxx.comsmtp_server xxx.smtp.com smtp_connect_timeout 30 router_id LVS_DEVEL }
vrrp_script Monitor_Nginx { script "/root/monitor_nginx.sh" interval 2 weight 2 }
vrrp_instance VI_1 { state MASTER #(主机为MASTER,备用机为BACKUP) interface eth0 #(HA监测网络接口) virtual_router_id 61 #(主、备机的virtual_router_id必须相同) #mcast_src_ip 192.168.166.203 #(多播的源IP,设置为本机外网IP,与VIP同一网卡)此项可不设置 priority 90 #(主、备机取不同的优先级,主机值较大,备份机值较小,值越大优先级越高) advert_int 1 #(VRRP Multicast广播周期秒数) authentication { auth_type PASS #(VRRP认证方式) auth_pass 1234 #(密码) } track_script { Monitor_Nginx #(调用nginx进程检测脚本) } virtual_ipaddress { 192.168.166.178 #(VRRP HA虚拟地址) } }
###BACKUP方面只需要修改state为BACKUP , priority比MASTER稍低就OK了
三:注:monitor_nginx.sh为监控nginx进程的脚本,内容如下
#!/bin/bash if [ "$(ps -ef | grep "nginx: master process"| grep -v grep )" == "" ] then /usr/local/nginx/sbin/nginx sleep 5 if [ "$(ps -ef | grep "nginx: master process"| grep -v grep )" == "" ] then killall keepalived fi fi
#chmod +x monitor_nginx.sh
四.启动keepalived service keepalived start 或 /usr/local/keepalived/sbin/keepalived -D -f /etc/keepalived/keepalived.conf
五.测试步骤
1. 访问VIP看是否能够正常访问后端的web 2. 停止其中一个web看是否能将访问转到另一台上 3. 停止两台nginx上任何一个nginx进程看监控进程脚本是否会自动启动nginx 4. 停止任何一台nginx上的keepalived进程看另一台是否接管vip
track_interface的意思是将Linux中你想监控的网络接口卡监控起来,当其中的一块出现故障是keepalived都将视为路由器出现故障。 这里请注意: virtual_router_id 61,同一组master/backup中,也就是如果你设置了多个VRRP,同一组这个ID必须相同,不然启动的时候主从都会把VIP给启动了
keepalived 通过发送和接收组播包中的同一个virtual_router_id 的中的成员的存活,来确定对方的不可用,一旦检测到对方的不可用,即会切换它的备份角色为主。 即:当真实机192.168.166.177上的keepalived 检测到 真实机192.168.166.203上的keepalived 不可用时,177上将使用vip:192.168.166.178对外服务并由backup角色转变为master
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