Nginx_master:192.168.5.129
Nginx_backup:192.168.5.131
Tomcat:192.168.5.132 端口:8080,9080
操作系统：CentOS6.5 x86_64
内核版本：2.6.32-696.el6.x86_64
Nginx版本：nginx/1.12.0 nginx-1.12.0
Keepalived版本：Keepalived v1.2.13
前端双Nginx+Keepalived，Nginx反向代理到后端tomcat集群实现负载均衡，Keepalived实现集群高可用，master_nginx故障后虚拟IP自动切换到backup_nginx。
主nginx：192.168.5.129
备nginx：192.168.5.131
虚拟IP：192.168.5.200
后端tomcat集群：192.168.5.132
后端每个主机都开启两个端口提供业务：8080,9080
Keepalived是一种用C编写的路由软件。该项目的主要目标是为Linux系统和基于Linux的基础设施提供简单而强大的负载平衡和高可用性设施。 负载平衡框架依赖于众所周知的广泛使用的Linux虚拟服务器（IPVS）内核模块，提供Layer4负载平衡。Keepalived实现了一组检查器，以动态和自适应地维护和管理负载平衡的服务器池，以保证其健康。另一方面，VRRP实现了高可用性 协议。VRRP是路由器故障切换的基础。此外，Keepalived实现了一组钩子到VRRP有限状态机，提供低级和高速协议交互。Keepalived框架可以单独使用或全部使用，以提供有弹性的基础设施。
[root@centos-3 src]# tar -xf jdk-8u111-linux-x64.gz
[root@centos-3src]# ln -s /usr/local/src/jdk
export JAVA_HOME=/usr/local/jbk
export PATH=$JAVA_HOME/bin:$JAVA_HOME/jre/bin:$PATH
export CLASSSPATH=:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JAVA_HOME/jre/lib
[root@controller src]#source /etc/profile
[root@centos-3 src]# java -version
java version "1.8.0_111"
Java(TM) SE Runtime Environment (build 1.8.0_111-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.111-b14, mixed mode)
[root@centos-3 src]# tar zxvf apache-tomcat-8.5.9.tar.gz
[root@centos-3 src]# ln -s /usr/local/src/apache-tomcat-8.5.9 /usr/local/tomcat
[root@centos-3 src]# chown -R root.root /usr/local/tomcat/
设置环境变量：
[root@centos-3 src]# tail -4 /etc/profile
export JAVA_HOME=/usr/local/jdk
export PATH=$JAVA_HOME/bin:$JAVA_HOME/jre/bin:$PATH
export CLASSPATH=.$CLASSPATH:$JAVA_HOME/lib:$JAVA_HOME/jre/lib:$JAVA_HOME/lib/tools.jar
export TOMCAT_HOME=/usr/local/tomcat/
[root@centos-3conf]# vim server.xml（第一个tomcat）
………………………………………………
<Connector port="9080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443" />
<!-- A "Connector" using the shared thread pool-->
<!--
<Connector executor="tomcatThreadPool"
port="9080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443" />
………………………………………………
<Host name="192.168.5.132" appBase="/tomcat/helloworld"
unpackWARs="true" autoDeploy="true">
<Context path="" docBase="" debug="0" reloadable="false" crossContext="true"/>（加上一句作用上面直接绑定的时候，下面这个必须要有,docBase="" 不然不得）
[root@centos-3 src]# cd /usr/local/tomcat2/conf （配置第二个tomcat配置文件）
[root@centos-3 conf]# vim server.xml（第一个tomcat）
………………………………………………
<Connector port="8080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443" />
<!-- A "Connector" using the shared thread pool-->
<!--
<Connector executor="tomcatThreadPool"
port="8080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443" />
………………………………………………
<Host name="192.168.5.132" appBase="/tomcat/helloworld2"
unpackWARs="true" autoDeploy="true">
<Context path="" docBase="" debug="0" reloadable="false" crossContext="true"/>
[root@centos-3 ~]# cd /tomcat/
[root@centos-3 tomcat]# ls
helloworld helloworld2
[root@centos-3 tomcat]# cd helloworld
[root@centos-3 helloworld]# ls
index.jsp
[root@centos-3 helloworld]# cat index.jsp
<HTML>
<HEAD>
<TITLE>JSP测试页面---HelloWorld!</TITLE>
</HEAD>
<BODY>
<h1>132 Hello World!</h1>
</BODY>
</HTML>
[root@centos-3 helloworld]# cd /tomcat/helloworld2/
[root@centos-3 helloworld2]# cat index.jsp
<HTML>
<HEAD>
<TITLE>JSP测试页面---HelloWorld!</TITLE>
</HEAD>
<BODY>
<h1>132 Hello World!--------2</h1>
</BODY>
</HTML>
[root@centos-3 helloworld2]# cd /usr/local/tomcat/bin/
[root@centos-3 bin]# ./catalina.sh start （启动tomcat）
Using CATALINA_BASE: /usr/local/tomcat
Using CATALINA_HOME: /usr/local/tomcat
Using CATALINA_TMPDIR: /usr/local/tomcat/temp
Using JRE_HOME: /usr/local/jbk
Using CLASSPATH: /usr/local/tomcat/bin/bootstrap.jar:/usr/local/tomcat/bin/tomcat-juli.jar
Tomcat started.
[root@centos-3 helloworld2]# curl 192.168.5.132:8080
<HTML>
<HEAD>
<TITLE>JSP测试页面---HelloWorld!</TITLE>
</HEAD>
<BODY>
<h1>132 Hello World!</h1>
</BODY>
</HTML>
[root@centos-3 helloworld2]# curl 192.168.5.132:9080
<HTML>
<HEAD>
<TITLE>JSP测试页面---HelloWorld!</TITLE>
</HEAD>
<BODY>
<h1>132 Hello World!--------2</h1>
</BODY>
</HTML>
[root@centos-3 helloworld2]#
[root@centos-1 ~]# vim /usr/local/nginx/conf/nginx.conf
upstream mysite {
server 192.168.5.132:9080 max_fails=3 fail_timeout=20s weight=2;（添加tomcat作为后端服务）
server 192.168.5.132:8080 max_fails=3 fail_timeout=20s weight=1;
}
server {
listen 80;
server_name 192.168.5.129;
#charset koi8-r;
#access_log logs/host.access.log main;
location / {
# root /web;
# index index.jsp index.php index.html index.htm;
proxy_pass http://mysite;
proxy_set_header Host 192.168.5.132;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwared-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwared-For $proxy_add_x_forwarded_for;
}
（意思是访问这个IP的时候都是反向代理到后端的这些主机）
location /status {
stub_status;
}
[root@centos-1 ~]# /usr/local/nginx/sbin/nginx -t
nginx: the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok
nginx: configuration file /usr/local/nginx/conf/nginx.conf test is successful
[root@centos-1 ~]# /usr/local/nginx/sbin/nginx -s reload
[root@centos-1 ~]# curl 192.168.5.129
<HTML>
<HEAD>
<TITLE>JSP测试页面---HelloWorld!</TITLE>
</HEAD>
<BODY>
<h1>132 Hello World!--------2</h1>
</BODY>
</HTML>
[root@centos-1 ~]# curl 192.168.5.129
<HTML>
<HEAD>
<TITLE>JSP测试页面---HelloWorld!</TITLE>
</HEAD>
<BODY>
<h1>132 Hello World!</h1>
</BODY>
</HTML>
[root@centos-1 ~]#
[root@centos-1 ~]# yum install -y keepalived
[root@centos-1 ~]# service keepalived start
[root@centos-1 ~]# service keepalived status
keepalived (pid 13083) 正在运行...
[root@centos-1 ~]# cd /script/
[root@centos-1 script]# cat sc.sh
#!/bin/bash
pgrep nginx > check.log
if [ $? -ne 0 ] ;then （当执行pgrep nginx时输出$?为0的时候证明nginx已经down掉，就把keepalived stop掉）
service keepalived stop >> /script/check.log
fi
[root@centos-1 ~]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
406552227@qq.com #接收警报的email地址,可以添加多个
}
notification_email_from root@localhost ###发件人地址
smtp_server 127.0.0.1 #发送邮件的服务器
smtp_connect_timeout 30###超时时间
router_id LVS_DEVEL##load balancer 的标识 ID,用于email警报
}
vrrp_script chk_nginx {
script "/script/sc.sh"####检测nginx状态的脚本路径
interval 2
weight -10
fall 2
rise 2
}
vrrp_instance VI_1 {
state MASTER ############ 辅机为 BACKUP
interface eth0####HA 监测网络接口 此项默认为eth0,因为本人在虚拟机下做测试所以将其改为eth2，可以用ifconfing
virtual_router_id 51#主、备机的 virtual_router_id 必须相同
mcast_src_ip 192.168.100.128 ###本机IP地址
priority 100########### 权值要比 back 高
advert_int 1 #主备之间的通告间隔秒数
authentication {
auth_type PASS###默认配置 主备切换时的验证
auth_pass 1111
}
virtual_ipaddress {
192.168.5.200/24####虚拟ip，vip的地址
}
track_script {
chk_nginx### 执行监控的服务
}
}
[root@centos-2 ~]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
406552227@qq.com
}
notification_email_from root@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_nginx {
script "/script/sc.sh"
interval 2
weight -10
fall 2
rise 2
}
vrrp_instance VI_1 {
state BACKUP
interface eth1
virtual_router_id 51
mcast_src_ip 192.168.100.131
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.5.200/24
}
track_script {
chk_nginx
}
}
[root@centos-1 ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:0d:f3:5d brd ff:ff:ff:ff:ff:ff
inet 192.168.5.129/24 brd 192.168.5.255 scope global eth0
inet 192.168.5.200/32 scope global eth0（vip被centos-1抢占着）
inet6 fe80::20c:29ff:fe0d:f35d/64 scope link
valid_lft forever preferred_lft forever
[root@centos-1 ~]# curl 192.168.5.200（访问vip地址测试）
<HTML>
<HEAD>
<TITLE>JSP测试页面---HelloWorld!</TITLE>
</HEAD>
<BODY>
<h1>132 Hello World!--------2</h1>
</BODY>
</HTML>
[root@centos-1 ~]# curl 192.168.5.200
<HTML>
<HEAD>
<TITLE>JSP测试页面---HelloWorld!</TITLE>
</HEAD>
<BODY>
<h1>132 Hello World!</h1>
</BODY>
</HTML>
[root@centos-1 ~]# /usr/local/nginx/sbin/nginx -s stop
[root@centos-1 ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:0d:f3:5d brd ff:ff:ff:ff:ff:ff
inet 192.168.5.129/24 brd 192.168.5.255 scope global eth0
inet6 fe80::20c:29ff:fe0d:f35d/64 scope link （vip已经退出centos-1）
valid_lft forever preferred_lft forever
[root@centos-1 ~]# service keepalived status
keepalived 已停
[root@centos-2 ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:50:56:2b:42:c1 brd ff:ff:ff:ff:ff:ff
inet 192.168.5.131/24 brd 192.168.5.255 scope global eth1
inet 192.168.5.200/32 scope global eth1（vip被centos-2抢占）
inet6 fe80::250:56ff:fe2b:42c1/64 scope link
valid_lft forever preferred_lft forever
[root@centos-2 ~]# curl 192.168.5.200
<HTML>
<HEAD>
<TITLE>JSP测试页面---HelloWorld!</TITLE>
</HEAD>
<BODY>
<h1>132 Hello World!</h1>
</BODY>
</HTML>
[root@centos-2 ~]#
[root@centos-2 ~]# curl 192.168.5.200
<HTML>
<HEAD>
<TITLE>JSP测试页面---HelloWorld!</TITLE>
</HEAD>
<BODY>
<h1>132 Hello World!--------2</h1>
</BODY>
</HTML>
因为这样做nginx+keepalived 会抢占资源，这样客户体验就不好，
为了keepalived设置不抢占资源：修改增加参数
两边设置backup
nopreempt（增加这项参数）
本文出自 “成为运维的路上” 博客，请务必保留此出处http://legehappy.blog.51cto.com/13251607/1962797
Nginx+Keepalived搭建高可用负载平衡WEB 集群
原文地址：http://legehappy.blog.51cto.com/13251607/1962797
