实验准备：
- 虚拟机172.18.250.77 安装nginx和httpd 实现负载均衡和反向代理
- 虚拟机172.18.250.78 安装tomcat
- 虚拟机172.18.250.79 安装tomcat
nginx反向代理和负载均衡
安装nginx和tomcat
]# rpm -ivh nginx-1.8.0-1.el6.ngx.x86_64.rpm
]# ls
apache-tomcat-7.0.55.tar.gz jdk-7u79-linux-x64.rpm
]# tar -xf apache-tomcat-7.0.55.tar.gz -C /usr/local/ //解压二进制编译包
]# cd /usr/local/
]# ln -s apache-tomcat-7.0.55/ tomcat //软链接
]# rpm -ivh jdk-7u79-linux-x64.rpm //安装官方的二进制jdk包
系统找java时是根据JAVA_HOME这个系统变量来寻找的,所以导出这个变量：
]# vim /etc/profile.d/java.sh
/usr/local/tomcat
JAVA_HOME=/usr/java/latest
PATH=$JAVA_HOME/bin:$PATH
export JAVA_HOME PATH
]# vim /etc/profile.d/tomcat.sh //导出tomcat路径到环境变量中
CATALINA_HOME=/usr/local/tomcat
PATH=$CATALINA_HOME/bin:$PATH
export CATALINA_BASE PATH
]# . /etc/profile.d/java.sh
]# . /etc/profile.d/tomcat.sh
]# echo $JAVA_HOME
/usr/bin/
]# echo $CATALINA_HOME
/usr/local/tomcat
配置nginx和tomcat，在250.78和250.79上
]# vim /etc/nginx/conf.d/default.conf
location / {
root /usr/share/nginx/html;
proxy_pass http://localhost:8080/ //所有请求nginx80端口的都反代到tomcat8080上
index index.html index.htm;
}
]# cd /usr/local/tomcat/webapps/
]# mkdir myapp //创建测试目录
]# cd myapp/
]# mkdir classes lib WEB-INF META-INF
]# vim index.jsp //提供测试页
<%@ page language="java" %>
<%@ page import="java.util.*" %>
<html>
<head>
<title>JSP Tset Page</title>
</head>
<body>
<% out.println("Hello World from 250.78");
%>
</body>
</html>
]# nginx //启动tomcat和nginx
]# catalina.sh start
Using CATALINA_BASE: /usr/local/tomcat
Using CATALINA_HOME: /usr/local/tomcat
Using CATALINA_TMPDIR: /usr/local/tomcat/temp
Using JRE_HOME: /usr/java/latest
Using CLASSPATH: /usr/local/tomcat/bin/bootstrap.jar:/usr/local/tomcat/bin/tomcat-juli.jar
Tomcat started.
然后直接可以用浏览器访问看是否可以访问。
配置nginx负载均衡
]# vim /etc/nginx/nginx.conf //在250.77上配置
upstream webserver {
server 172.18.250.78:80;
server 172.18.250.79:80;
}
]# vim /etc/nginx/conf.d/default.conf
location / {
root /usr/share/nginx/html;
proxy_pass http://webserver/;
index index.html index.htm;
}
]# nginx
]# curl http://172.18.250.77/myapp/index.jsp
<title>JSP Tset Page</title>
<body>
Hello World from 250.78 </body>
]# curl http://172.18.250.77/myapp/index.jsp //在服务器上curl请求，实现了负载均衡
<title>JSP Tset Page</title>
<body>
Hello World from 250.79 </body>
基于session sticky实现会话保持
]# vim /etc/nginx/nginx.conf
upstream webserver {
server 172.18.250.78:80;
server 172.18.250.79:80;
ip_hash;
}
源地址hash后，多次刷新，都是反代到相同的一台服务器上，保持了会话
httpd的反向代理
]# yum -y install httpd //三台服务器全部装上httpd
]# nginx -s stop //停止nginx
配置httpd,实现反向代理：
]# httpd -M //httpd的反代有三种方式
proxy_ajp_module (shared) //ajp协议的反代模块
proxy_balancer_module (shared) //负载均衡模块
proxy_http_module (shared) //http协议的反代模块
还有一种模块是mod_jk，需要手动安装加载使用
1、配置http协议的反代模块
]# cd /etc/httpd/conf.d/
]# vim http_proxy_tomcat.conf
<VirtualHost *:80>
ServerName web.magedu.com
ProxyVia On //用于在多级代理中控制代理请求的流向
ProxyRequests Off //关闭正向代理
ProxyPreserveHost On //如果启用此功能，代理会将用户请求报文中的Host:行发送给后端的服务器，而不再使用ProxyPass指定的服务器地址
<Proxy *> //允许反代任何请求
Require all granted
</Proxy>
ProxyPass / http://localhost:8080/ //反代到指定服务器
ProxyPassReverse / //用于让apache调整HTTP重定向响应报文中的Location、Content-Location及URI标签所对应的URL，在反向代理环境中必须使用此指令避免重定向报文绕过proxy服务器。
<Location />
Require all granted
</Location>
</VirtualHost>
根据mod_jk进行反代
]# ls
tomcat-connectors-1.2.40-src.tar.gz
]# tar -xf tomcat-connectors-1.2.40-src.tar.gz
]# cd tomcat-connectors-1.2.40-src/native
]# ./configure --with-apxs=/usr/bin/apxs //编译httpd模块
]# make && make install
]# /etc/httpd/conf.d //在250.78上
]# vim mod_jk.conf
LoadModule jk_module modules/mod_jk.so //加载mod_jk
JkWorkersFile /etc/httpd/conf.d/workers.properties //jk的配置参数文件
JkLogFile logs/mod_jk.log //jk代理日志
JkLogLevel debug //jk的日志级别
JkMount /* TomcatB //反代到哪台主机上
JkMount /jk_status StatB //开启jk状态页
]# vim workers.properties
worker.list=TomcatB,StatB //worker的列表
worker.TomcatB.host=172.18.250.78 //worker对应的主机
worker.TomcatB.port=8009 //worker对应的端口
worker.TomcatB.type=ajp13 //worker对应的tomcat的协议
worker.StatB.type=status //状态页
250.79上只需要把TomcatB改成TomcatA就行，并改下IP地址
至此，一个基于mod_jk模块与后端名为TomcatA的worker通信的配置已经完成，重启httpd服务即可生效
httpd的负载均衡和session sticky（250.77上）
基于http协议的负载均衡至tomcat
]# cd /etc/httpd/conf.d/
]# vim http_balance_tomcat.conf
<proxy balancer://webserver>
BalancerMember http://172.18.250.78:8080 loadfactor=1 //loadfactor表示权重
BalancerMember http://172.18.250.79:8080 loadfactor=2
ProxySet lbmethod=byrequests //定义调度算法
</proxy>
<VirtualHost *:80>
ServerName tc.magedu.com
ProxyRequests Off
ProxyPreserveHost On
ProxyVia On
<Proxy *>
Require all granted
</Proxy>
Proxypass / balancer://webserver/
ProxypassReverse / balancer://webserver/
<Location />
Require all granted
</Location>
</VirtualHost>
后端两台需要使用http_proxy_tomcat.conf的配置文件
设置session_sticky
]# vim http_balance_tomcat.conf
Header add Set-Cookie "ROUTEID=.%{BALANCER_WORKER_ROUTE}e; path=/" env=BALANCER_ROUTE_CHANGED
<proxy balancer://webserver>
BalancerMember http://172.18.250.78:8080 route=TomcatA
BalancerMember http://172.18.250.79:8080 route=TomcatB
ProxySet lbmethod=byrequests
ProxySet stickysession=ROUTEID //在将某请求调度至某worker后，源于此址的所有后续请求都将直接调度至此worker，实现将用户session与某worker绑定。
</proxy>
<VirtualHost *:80>
ServerName tc.magedu.com
ProxyRequests Off
ProxyPreserveHost On
ProxyVia On
<Proxy *>
Require all granted
</Proxy>
ProxyPass / balancer://webserver/
ProxyPassReverse / balancer://webserver/
<Location />
Require all granted
</Location>
</VirtualHost>
基于ajp协议负载均衡至tomcat
]# cd /etc/httpd/conf.d/
]# vim ajp_balance_tomcat.conf
<proxy balancer://webserver>
BalancerMember ajp://172.18.250.78:8009 loadfactor=1
BalancerMember ajp://172.18.250.79:8009 loadfactor=2
ProxySet lbmethod=byrequests
</proxy>
<VirtualHost *:80>
ServerName tc.magedu.com
ProxyRequests Off
ProxyPreserveHost On
ProxyVia On
<Proxy *>
Require all granted
</Proxy>
Proxypass / balancer://webserver/
ProxypassReverse / balancer://webserver/
<Location />
Require all granted
</Location>
</VirtualHost>
后端两台需要使用ajp_proxy_tomcat.conf的配置文件
基于session_sticky的会话保持
]# vim ajp_balance_tomcat.conf
Header add Set-Cookie "ROUTEID=.%{BALANCER_WORKER_ROUTE}e; path=/" env=BALANCER_ROUTE_CHANGED
<proxy balancer://webserver>
BalancerMember ajp://172.18.250.78:8009 route=TomcatA
BalancerMember ajp://172.18.250.79:8009 route=TomcatB
ProxySet lbmethod=byrequests
ProxySet stickysession=ROUTEID
</proxy>
<VirtualHost *:80>
ServerName tc.magedu.com
ProxyRequests Off
ProxyPreserveHost On
ProxyVia On
<Proxy *>
Require all granted
</Proxy>
ProxyPass / balancer://webserver/
ProxyPassReverse / balancer://webserver/
<Location />
Require all granted
</Location>
</VirtualHost>
基于mod_jk来实现负载均衡
]# vim mod_jk.conf
LoadModule jk_module modules/mod_jk.so
JkWorkersFile /etc/httpd/conf.d/workers.properties
JkLogFile logs/mod_jk.log
JkLogLevel debug
JkMount /* webserver //改成服务器池名称就行
JkMount /jk_status StatA
]# vim workers.properties
worker.list=webserver,StatA
worker.TomcatA.host=172.18.250.78
worker.TomcatA.port=8009
worker.TomcatA.type=ajp13
worker.TomcatA.lbfactor=1
worker.TomcatB.host=172.18.250.79
worker.TomcatB.port=8009
worker.TomcatB.type=ajp13
worker.TomcatB.lbfactor=2
worker.webserver.type=lb //类型为负载均衡
worker.webserver.balance_workers=TomcatA,TomcatB
worker.StatA.type=status
基于session_sticky的会话保持
]# vim workers.properties
worker.list=webserver,StatA
worker.TomcatA.host=172.18.250.78
worker.TomcatA.port=8009
worker.TomcatA.type=ajp13
worker.TomcatA.lbfactor=1
worker.TomcatB.host=172.18.250.79
worker.TomcatB.port=8009
worker.TomcatB.type=ajp13
worker.TomcatB.lbfactor=2
worker.webserver.type=lb
worker.webserver.balance_workers=TomcatA,TomcatB
worker.webserver.sticky_session=1 //开启会话粘性，默认是开启的
worker.StatA.type=status
mod_jk除了开启会话粘性外，还需在各个节点tomcat的配置文件server.xml上添加jvmRouet
<Engine name="Catalina" defaultHost="localhost" jvmROUTE="TomcatA"> //250.78上
<Engine name="Catalina" defaultHost="localhost" jvmROUTE="TomcatB"> //250.79上
这样就可以实现了。在做实验时每做一步都在浏览器中测试一下，因为测试步骤过于繁琐这里就不介绍了。
