喜欢搞Nginx，这两天研究了一下Nginx的负载配置
Nginx平台搭建：
单Nginx负载均衡：
熟悉上面的配置之后，今天我再来搞Nginx + Keepalived 的配置，具体拓扑如下：
两台前端Nginx，任意一台挂了另一台会接管岩机Nginx的虚拟Ip，前面还可以做一个DNS轮询，没在线上环境跑过，不知性能如何勒！
一、安装Keepalived
ln -s /usr/src/kernels/2.6.18-194.el5-i686/ /usr/src/linux tar zxvf keepalived-1.1.15.tar.gz cd keepalived-1.1.15 ./configure --prefix=/usr/local/keepalived 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/ mkdir /etc/keepalived cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/ #主配置文件 cp -v /usr/local/keepalived/sbin/keepalived /usr/sbin/ service keepalived start|stop #启动、停止服务
二、配置Keepalived
/etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs { notification_email {
} notification_email_from smtp_server 192.168.200.1 smtp_connect_timeout 30 router_id LVS_DEVEL }vrrp_script chk_nginx { script "/usr/local/keepalived/check_http.sh" interval 2 weight 2 }
vrrp_instance VI_1 { state MASTER interface eth0 virtual_router_id 51 #同一个vrrp_instance，这个ID要相同 priority 100 #同一个vrrp_instance，这个值master要大于backup advert_int 1 authentication { auth_type PASS auth_pass 123456 } track_script { chk_nginx } virtual_ipaddress { 192.168.93.144 #定义vip，也就是对外IP，可以写多个（换行） } }
vrrp_instance VI_2 { state BACKUP interface eth0 virtual_router_id 52 priority 50 advert_int 1 authentication { auth_type PASS auth_pass 123456 } virtual_ipaddress { 192.168.93.145 } }
global_defs 是全局配置，定义邮件报警，我无视它了。
vrrp_script 定义一个监控脚本，作用：发现Nginx挂了，马上关掉keepalived
vrrp_instance 定义一个虚拟IP，对外服务的，其中还有个track_script ，这个就是调用刚才定义的监控脚本
另外一台前端Nginx的Keepalived配置如下：
! Configuration File for keepalived
global_defs { notification_email {
} notification_email_from smtp_server 192.168.200.1 smtp_connect_timeout 30 router_id LVS_DEVEL }vrrp_script chk_nginx { script "/usr/local/keepalived/check_http.sh" interval 2 weight 2 }
vrrp_instance VI_1 { state BACKUP interface eth0 virtual_router_id 51 priority 50 advert_int 1 authentication { auth_type PASS auth_pass 123456 } virtual_ipaddress { 192.168.93.144 } }
vrrp_instance VI_2 { state MASTER interface eth0 virtual_router_id 52 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 123456 } track_script { chk_nginx } virtual_ipaddress { 192.168.93.145 } }
另外监控脚本check_http.sh可以自己发挥，原则就是发现Nginx挂了就杀掉keepalived就行，写法多种
pid=`ps -C nginx --no-header | wc -l` if [ $pid -eq 0 ] then /usr/local/nginx/sbin/nginx sleep 5 newpid=`ps -C nginx --no-header | wc -l` if [ $newpid -eq 0 ] then killall keepalived fi fi
Nginx的配置就不多说
启动服务
/usr/local/nginx/sbin/nginx service keepalived start ps -aef | grep keepalived root 28742 3288 0 03:21 pts/1 00:00:00 grep keepalived root 31674 1 0 Oct31 ? 00:00:00 keepalived -D root 31676 31674 0 Oct31 ? 00:00:00 keepalived -D root 31677 31674 0 Oct31 ? 00:00:02 keepalived -D
三、测试
主Nginx
ip add
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000 link/ether 00:0c:29:e0:a3:bf brd ff:ff:ff:ff:ff:ff inet 192.168.93.137/24 brd 192.168.93.255 scope global eth0 inet 192.168.93.144/32 scope global eth0 inet6 fe80::20c:29ff:fee0:a3bf/64 scope link valid_lft forever preferred_lft forever备Nginx
ip add
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000 link/ether 00:0c:29:ee:a6:22 brd ff:ff:ff:ff:ff:ff inet 192.168.93.138/24 brd 192.168.93.255 scope global eth0 inet 192.168.93.145/32 scope global eth0 inet6 fe80::20c:29ff:feee:a622/64 scope link valid_lft forever preferred_lft foreve我把主Nginx服务停掉之后：
主Nginx
ip add
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000 link/ether 00:0c:29:e0:a3:bf brd ff:ff:ff:ff:ff:ff inet 192.168.93.137/24 brd 192.168.93.255 scope global eth0 inet6 fe80::20c:29ff:fee0:a3bf/64 scope link valid_lft forever preferred_lft forever备Nginx
ip add
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000 link/ether 00:0c:29:ee:a6:22 brd ff:ff:ff:ff:ff:ff inet 192.168.93.138/24 brd 192.168.93.255 scope global eth0 inet 192.168.93.145/32 scope global eth0 inet 192.168.93.144/32 scope global eth0 inet6 fe80::20c:29ff:feee:a622/64 scope link valid_lft forever preferred_lft forever备机已经接管了主的ip，然后再把主机的服务恢复：
主Nginx
ip add
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000 link/ether 00:0c:29:e0:a3:bf brd ff:ff:ff:ff:ff:ff inet 192.168.93.137/24 brd 192.168.93.255 scope global eth0 inet 192.168.93.144/32 scope global eth0 inet6 fe80::20c:29ff:fee0:a3bf/64 scope link valid_lft forever preferred_lft forever备Nginx
ip add
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000 link/ether 00:0c:29:ee:a6:22 brd ff:ff:ff:ff:ff:ff inet 192.168.93.138/24 brd 192.168.93.255 scope global eth0 inet 192.168.93.145/32 scope global eth0 inet6 fe80::20c:29ff:feee:a622/64 scope link valid_lft forever preferred_lft forever配置完成！