1、演示環境：
IP | 操作系統 | 部署程序 |
192.168.1.143 | CentOS 7.6 | Apache |
192.168.1.144 | CentOS 7.6 | Tomcat |
192.168.1.145 | CentOS 7.6 | Tomcat |
2、192.168.1.144節點創建測試頁：
# vim /usr/local/tomcat/webapps/ROOT/test.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<html>
<head><title>TomcatA</title></head>
<body>
<h1><font color="red">TomcatA</font></h1>
<table border="1">
<tr>
<td>Session ID</td>
<td><%= session.getId() %></td>
</tr>
<tr>
<td>Created ON</td>
<td><%= session.getCreationTime() %></td>
</tr>
</table>
</body>
</html>
3、192.168.1.145節點創建測試頁：
# vim /usr/local/tomcat/webapps/ROOT/test.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<html>
<head><title>TomcatB</title></head>
<body>
<h1><font color="blue">TomcatB</font></h1>
<table border="1">
<tr>
<td>Session ID</td>
<td><%= session.getId() %></td>
</tr>
<tr>
<td>Created ON</td>
<td><%= session.getCreationTime() %></td>
</tr>
</table>
</body>
</html>
4、192.168.1.144節點新增jvmRoute參數：
# cd /usr/local/tomcat/conf
# cp server.xml server.xml.bak
# vim server.xml
<Engine name="Catalina" defaultHost="localhost">修改爲
<Engine name="Catalina" defaultHost="localhost" jvmRoute="TomcatA">
5、192.168.1.145節點新增jvmRoute參數：
# cd /usr/local/tomcat/conf
# cp server.xml server.xml.bak
# vim server.xml
<Engine name="Catalina" defaultHost="localhost">修改爲
<Engine name="Catalina" defaultHost="localhost" jvmRoute="TomcatB">
6、分別啓動192.168.1.144節點和192.168.1.145節點上的Tomcat：
# catalina.sh stop # catalina.sh configtest # catalina.sh start # ss -tunlp | grep -w :8009
7、192.168.1.143節點安裝Apache實現反代、動靜分離和負載均衡：
# yum -y install httpd
# cd /etc/httpd/conf
# cp httpd.conf httpd.conf.bak
# vim httpd.conf
Ø 新增代碼：ServerName localhost:80
Ø 註釋代碼：DocumentRoot "/var/www/html"
# httpd -t # systemctl start httpd.service # ss -tunlp | grep -w :80
# httpd -M | grep proxy
（1）配置status狀態頁面：
# vim /etc/httpd/conf/httpd.conf，末尾新增如下代碼：
<Location /server-status>
SetHandler server-status
Require all granted
</Location>
備註：此處未做訪問控制，status狀態頁面用於測試反代功能
# httpd -t # systemctl reload httpd.service # ss -tunlp | grep -w :80
本地瀏覽器訪問：
192.168.1.143
192.168.1.143/server-status
（2）配置虛擬主機：# vim /etc/httpd/conf.d/vhosts.conf
<Proxy balancer://testcluster>
BalancerMember ajp://192.168.1.144:8009 loadfactor=1 route=TomcatA
BalancerMember ajp://192.168.1.145:8009 loadfactor=1 route=TomcatB
</Proxy>
<VirtualHost *:80>
ServerName web.qiuyue.com
ProxyVia On
ProxyRequests Off
ProxyPreserveHost Off
<Proxy *>
Require all granted
</Proxy>
ProxyPass /server-status !
ProxyPass / balancer://testcluster/
ProxyPa***everse / balancer://testcluster/
<Location />
Require all granted
</Location>
</VirtualHost>
# httpd -t # systemctl reload httpd.service # ss -tunlp | grep -w :80
備註：常用指令說明
Ø ProxyVia On：每個請求和響應報文的HTTP首部均添加Via，用於在多級代理中控制代理請求的流向
Ø ProxyRequests Off：關閉Apache正向代理功能，開啓反代功能必須關閉正向代理功能
Ø ProxyPreserveHost Off：啓用此功能，代理會將用戶請求報文中的Host:行發送給後端服務器，而不再使用ProxyPass指定的服務器地址，如果想在反代中支持虛擬主機，則需要開啓此項
Ø ProxyPass PATH !|URL：將後端服務器某URL與當前服務器的某虛擬路徑關聯起來作爲提供服務的路徑，PATH爲當前服務器上的某虛擬路徑，URL爲後端服務器上某URL路徑，使用此指令時必須將ProxyRequests的值設置爲Off，而且如果PATH以/結尾，則對應的URL也必須以/結尾，反之亦然
Ø ProxyPa***everse：讓Apache調整HTTP重定向響應報文中的Location、Content-Location及URI標籤所對應的URL，在反代環境中必須使用此指令避免重定向報文繞過Proxy服務器
（3）本地瀏覽器訪問：
192.168.1.143
192.168.1.143/server-status
192.168.1.143/test.jsp
輪詢顯示，且Session ID一直在變：
8、 配置proxy_balancer_module內置的Load Balancer Manager：# vim /etc/httpd/conf.d/vhosts.conf
<Proxy balancer://testcluster>
BalancerMember ajp://192.168.1.144:8009 loadfactor=1 route=TomcatA
BalancerMember ajp://192.168.1.145:8009 loadfactor=1 route=TomcatB
</Proxy>
<VirtualHost *:80>
ServerName web.qiuyue.com
ProxyVia On
ProxyRequests Off
ProxyPreserveHost Off
<Proxy *>
Require all granted
</Proxy>
ProxyPass /server-status !
ProxyPass /balancer-manager !
ProxyPass / balancer://testcluster/
ProxyPa***everse / balancer://testcluster/
<Location />
Require all granted
</Location>
<Location /balancer-manager>
SetHandler balancer-manager
Require all granted
</Location>
</VirtualHost>
# httpd -t # systemctl reload httpd.service # ss -tunlp | grep -w :80
本地瀏覽器訪問：192.168.1.143/balancer-manager
9、實現session會話保持：# vim /etc/httpd/conf.d/vhosts.conf
Header add Set-Cookie "ROUTEID=.%{BALANCER_WORKER_ROUTE}e; path=/" env=BALANCER_ROUTE_CHANGED
<Proxy balancer://testcluster>
BalancerMember ajp://192.168.1.144:8009 loadfactor=1 route=TomcatA
BalancerMember ajp://192.168.1.145:8009 loadfactor=1 route=TomcatB
ProxySet lbmethod=bytraffic stickysession=ROUTEID
</Proxy>
<VirtualHost *:80>
ServerName web.qiuyue.com
ProxyVia On
ProxyRequests Off
ProxyPreserveHost Off
<Proxy *>
Require all granted
</Proxy>
ProxyPass /server-status !
ProxyPass /balancer-manager !
ProxyPass / balancer://testcluster/
ProxyPa***everse / balancer://testcluster/
<Location />
Require all granted
</Location>
<Location /balancer-manager>
SetHandler balancer-manager
Require all granted
</Location>
</VirtualHost>
備註：lbmethod爲Apache實現負載均衡的調度方法，默認爲byrequests，即基於請求次數進行調度；bytraffic爲基於流量進行調度；bybusyness爲基於繁忙程序進行調度。
# httpd -t # systemctl reload httpd.service # ss -tunlp | grep -w :80
本地瀏覽器訪問：
192.168.1.143/test.jsp，無論如何刷新，頁面都不會改變：
360安全瀏覽器F12：
備註：關閉瀏覽器，重新打開並訪問192.168.1.143/test.jsp，會基於新的Cookie進行會話保持
192.168.1.143/balancer-manager
