说明:
keepalived实现nginx发生故障时,自动切换,实现nginx反向代理的高可用。
环境:
CentOS6.4 64bit; Jdk6.tar.gz Aapache-tomcat-6.0.41.tar.gz nginx-1.4.2.tar.gz keepalived-1.1.19.tar.gz
主机规划:
keepalived-master: 192.168.115.10 keepalived-slave : 192.168.115.20 tomcat1 : 192.168.115.30 tomcat2 : 192.168.115.40
JDK安装:
tar zxvf JDK6.tar.gz
vi /etc/profile.d/jdk.sh
export JAVA_HOME=/usr/local/jdk6 export CALASS_PATH=$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar export JAVA_BIN=$JAVA_HOME/bin export PATH=$PATH:$JAVA_HOME/bin
Tomcat安装:
tar zxvf Aapache-tomcat-6.0.41.tar.gz mv ./tomcat /usr/local/tomcat1 cp -r /usr/local/tomcat1 /usr/local/tomcat2
修改tomcat2中server.xml定义的三个端口: shutdown端口"8005 ajp端口: 8009 http端口: 8080
nginx的安装:
http://yujianglei.blog.51cto.com/7215578/1725587
启动脚本:
http://yujianglei.blog.51cto.com/7215578/1561565
安装keepalived:
http://yujianglei.blog.51cto.com/7215578/1725586
修改配置文件:
! Configuration File for keepalived global_defs { notification_email { 1075841124@qq.com } notification_email_from Alexandre.Cassen@firewall.loc smtp_server 127.0.0.1 smtp_connect_timeout 30 router_id LVS_DEVEL } vrrp_script chk_nginx { script "kill all -0 nginx" interval 1 weight -2 fall 2 rise 1} 这是keepalived对nginx的健康监测 vrrp_instance VI_1 { state MASTER 主为MASTER。备为BACKUP interface eth0 virtual_router_id 51 主和备相同 priority 100 主高备低 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.115.222 192.168.115.111 192.168.115.99 } track_script { chk_nginx } }
观察:
MASTER:
/etc/init.d/keepalived start
ip addr show看到如下信息:
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:7e:20:10 brd ff:ff:ff:ff:ff:ff inet 192.168.115.10/24 brd 192.168.115.255 scope global eth0 inet 192.168.115.222/32 scope global eth0 inet 192.168.115.111/32 scope global eth0 inet 192.168.115.99/32 scope global eth0 inet6 fe80::20c:29ff:fe7e:2010/64 scope link valid_lft forever preferred_lft forever
BACKUP:
/etc/init.d/keepalived start
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:05:ff:b3 brd ff:ff:ff:ff:ff:ff inet 192.168.115.20/24 brd 192.168.115.255 scope global eth0 inet6 fe80::20c:29ff:fe05:ffb3/64 scope link valid_lft forever preferred_lft forever
停止master上的keepalived后在观察backup:
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:05:ff:b3 brd ff:ff:ff:ff:ff:ff inet 192.168.115.20/24 brd 192.168.115.255 scope global eth0 inet 192.168.115.222/32 scope global eth0 inet 192.168.115.111/32 scope global eth0 inet 192.168.115.99/32 scope global eth0 inet6 fe80::20c:29ff:fe05:ffb3/64 scope link valid_lft forever preferred_lft forever
配置nginx代理tomcat
http模块中添加:
upstream tomcat { server 192.168.115.30:8080 weight=3; server 192.168.115.30:8081 weight=3; server 192.168.115.40:8080 weight=3; server 192.168.115.40:8081 weight=3; location / { proxy_pass http://tomcat; }
Nginx配置完毕。此时测试:
192.168.115.10:MASTER /etc/init.d/keepalived start server nginx start 192.168.115.20:SLAVE /etc/init.d/keepalived start server nginx start
注意此时,在keepalived上配置的虚拟IP是:
192.168.115.222 192.168.115.111 192.168.115.99
在浏览器中访问任何一个VIP,nginx都能代理到后方。并且能正常访问到TOMCAT主页面。
现在把MASTER上的nginx stop,观察
192.168.115.10 MASTER: service nginx stop
ip addr show 观察:发现VIP消失
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:7e:20:10 brd ff:ff:ff:ff:ff:ff inet 192.168.115.10/24 brd 192.168.115.255 scope global eth0 inet6 fe80::20c:29ff:fe7e:2010/64 scope link valid_lft forever preferred_lft forever
于是观察BACKUP上,ip addr show 观察已经获取VIP了。
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:05:ff:b3 brd ff:ff:ff:ff:ff:ff
inet 192.168.115.20/24 brd 192.168.115.255 scope global eth0
inet 192.168.115.222/32 scope global eth0
inet 192.168.115.111/32 scope global eth0
inet 192.168.115.99/32 scope global eth0
inet6 fe80::20c:29ff:fe05:ffb3/64 scope link
valid_lft forever preferred_lft forever
再用浏览器访问VIP,看是否能问到tomcat页面。
依然能访问到,说明keepalived起到作用了。 这就是keepalived双机热备,故障转移的表现功能所在。在Nginx+Keepalived的架构上,nginx双 机实现了反向代理的高可用。一台nginx挂掉后,依然不会影响访问。前端负载均衡已经解决了,但是后 端的tomcat服务器挂掉后,该如何呢?keepalived是无法做到对后端服务器的健康检测的。这需要 Nginx的功能。