HTTP + Tomcat 实现负载均衡
1、实验拓扑
2、各个虚机的软件安装
2.1 HTTPD
2.1.1 HTTPD 安装
[root@Tang-11 ~]# ipinfo
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.13 netmask 255.255.255.0 broadcast 192.168.1.255
--
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
[root@Tang-11 ~]# yum install httpd -y
2.1.2 HTTPD 启动
[root@Tang-11 ~]# systemctl start httpd.service
[root@Tang-11 ~]# ss -tnl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 *:22 *:*
LISTEN 0 100 127.0.0.1:25 *:*
LISTEN 0 128 :::80 :::*
LISTEN 0 128 :::22 :::*
LISTEN 0 100 ::1:25 :::*
2.1.3 HTTPD 访问
2.1.4 HTTPD 加载的模块，确保已经加载了所需要使用的模块
[root@Tang-11 ~]# httpd -M
AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using fe80::20c:29ff:fee9:9f90. Set the 'ServerName' directive globally to suppress this message
Loaded Modules:
core_module (static)
so_module (static)
http_module (static)
... ...
systemd_module (shared)
cgi_module (shared)
2.2 Tomcat - 2
2.2.1 Tomcat 安装
[root@Tang-6 ~]# ipinfo
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.12 netmask 255.255.255.0 broadcast 192.168.1.255
--
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
[root@Tang-6 ~]# yum list all tomcat*
Installed Packages
tomcat.noarch 7.0.76-9.el7_6 @base
tomcat-admin-webapps.noarch 7.0.76-9.el7_6 @base
tomcat-docs-webapp.noarch 7.0.76-9.el7_6 @base
tomcat-el-2.2-api.noarch 7.0.76-9.el7_6 @base
tomcat-jsp-2.2-api.noarch 7.0.76-9.el7_6 @base
tomcat-lib.noarch 7.0.76-9.el7_6 @base
tomcat-servlet-3.0-api.noarch 7.0.76-9.el7_6 @base
tomcat-webapps.noarch 7.0.76-9.el7_6 @base
Available Packages
tomcat-javadoc.noarch 7.0.76-9.el7_6 base
tomcat-jsvc.noarch 7.0.76-9.el7_6 base
tomcat-native.x86_64 1.2.21-1.el7 epel
tomcatjss.noarch 7.2.1-8.el7_6 base
[root@Tang-6 ~]# yum install tomcat.noarch tomcat-admin-webapps.noarch tomcat-docs-webapp.noarch tomcat-webapps.noarch -y
2.2.2 Tomcat 启动
[root@Tang-6 ~]# systemctl start tomcat.service
[root@Tang-6 ~]# ss -tnl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 *:22 *:*
LISTEN 0 100 127.0.0.1:25 *:*
LISTEN 0 100 :::8009 :::*
LISTEN 0 100 :::8080 :::*
LISTEN 0 128 :::22 :::*
LISTEN 0 100 ::1:25 :::*
LISTEN 0 1 ::ffff:127.0.0.1:8005 :::*
2.2.3 Tomcat 访问
2.3 Tomcat - 1
2.3.1 Tomcat 安装
[root@Tang-5 ~]# ipinfo
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.11 netmask 255.255.255.0 broadcast 192.168.1.255
--
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
[root@Tang-5 ~]# yum list all tomcat*
Installed Packages
tomcat.noarch 7.0.76-9.el7_6 @base
tomcat-admin-webapps.noarch 7.0.76-9.el7_6 @base
tomcat-docs-webapp.noarch 7.0.76-9.el7_6 @base
tomcat-el-2.2-api.noarch 7.0.76-9.el7_6 @base
tomcat-jsp-2.2-api.noarch 7.0.76-9.el7_6 @base
tomcat-lib.noarch 7.0.76-9.el7_6 @base
tomcat-servlet-3.0-api.noarch 7.0.76-9.el7_6 @base
tomcat-webapps.noarch 7.0.76-9.el7_6 @base
Available Packages
tomcat-javadoc.noarch 7.0.76-9.el7_6 base
tomcat-jsvc.noarch 7.0.76-9.el7_6 base
tomcat-native.x86_64 1.2.21-1.el7 epel
tomcatjss.noarch 7.2.1-8.el7_6 base
[root@Tang-5 ~]# yum install tomcat.noarch tomcat-admin-webapps.noarch tomcat-docs-webapp.noarch tomcat-webapps.noarch -y
2.3.2 Tomcat 启动
[root@Tang-5 ~]# systemctl start tomcat.service
[root@Tang-5 ~]# ss -tnl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 *:22 *:*
LISTEN 0 100 127.0.0.1:25 *:*
LISTEN 0 100 :::8009 :::*
LISTEN 0 100 :::8080 :::*
LISTEN 0 128 :::22 :::*
LISTEN 0 100 ::1:25 :::*
LISTEN 0 1 ::ffff:127.0.0.1:8005 :::*
2.3.3 Tomcat 访问
3、Tomcat 冷部署一个测试类应用
3.1 Tomcat - 1
3.1.1 创建相关目录
[root@Tang-6 ~]# mkdir -pv /appdata/webapps/ROOT/{lib,classes,WEB-INF}
mkdir: created directory ‘/appdata’
mkdir: created directory ‘/appdata/webapps’
mkdir: created directory ‘/appdata/webapps/ROOT’
mkdir: created directory ‘/appdata/webapps/ROOT/lib’
mkdir: created directory ‘/appdata/webapps/ROOT/classes’
mkdir: created directory ‘/appdata/webapps/ROOT/WEB-INF’
[root@Tang-6 ~]# mkdir /appdata/webapps/test
3.1.2 创建相关文件
[root@Tang-6 ~]# cat /appdata/webapps/test/index.jsp
<%@ page language="java" %>
<html>
<head><title>TomcatA</title></head>
<body>
<h1><font color="red">Tang-6</font></h1>
<table align="centre" border="1">
<tr>
<td>Session ID</td>
<% session.setAttribute("Tang","Tang"); %>
<td><%= session.getId() %></td>
</tr>
<tr>
<td>Created on</td>
<td><%= session.getCreationTime() %></td>
</tr>
</table>
</body>
</html>
[root@Tang-6 ~]# tree /appdata/webapps/
/appdata/webapps/
├── ROOT
│ ├── classes
│ ├── lib
│ └── WEB-INF
└── test
└── index.jsp
5 directories, 1 file
3.1.3 修改 Tomcat 配置文件，并重启服务
### 在 </Engine> </Engine> 之间添加一个 HOST ###
[root@Tang-6 ~]# vim /etc/tomcat/server.xml
<Engine name="Catalina" defaultHost="localhost" jvmRoute="Tomcat-Tang-6">
<Host name="localhost" appBase="/appdata/webapps" unpackWARs="true" autoDeploy="true">
<Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
prefix="node1_access" suffix=".log"
pattern="%h %l %u %t "%r" %s %b" />
<Context path="/test" docBase="test" reloadable="">
<Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
prefix="Tang-6_test_access_" suffix=".log"
pattern="%h %l %u %t "%r" %s %b" />
</Context>
</Host>
</Engine>
[root@Tang-6 ~]# systemctl restart tomcat.service
3.1.4 修改 WIN7 HOSTS 文件，进行访问，并查看相关 log
3.1.5 查看相关 log
[root@Tang-6 ~]# tail /var/log/tomcat/Tang-6_test_access_2019-11-03.log
192.168.1.6 - - [03/Nov/2019:20:42:11 +0800] "GET /test/ HTTP/1.1" 200 321
192.168.1.6 - - [03/Nov/2019:20:42:15 +0800] "GET /test/ HTTP/1.1" 200 321
192.168.1.6 - - [03/Nov/2019:20:42:16 +0800] "GET /test/ HTTP/1.1" 200 321
192.168.1.6 - - [03/Nov/2019:20:42:16 +0800] "GET /test/ HTTP/1.1" 200 321
192.168.1.6 - - [03/Nov/2019:20:42:16 +0800] "GET /test/ HTTP/1.1" 200 321
192.168.1.6 - - [03/Nov/2019:20:42:16 +0800] "GET /test/ HTTP/1.1" 200 321
3.2 Tomcat - 2
3.2.1 创建相关目录
[root@Tang-5 ~]# mkdir -pv /appdata/webapps/ROOT/{lib,classes,WEB-INF}
mkdir: created directory ‘/appdata’
mkdir: created directory ‘/appdata/webapps’
mkdir: created directory ‘/appdata/webapps/ROOT’
mkdir: created directory ‘/appdata/webapps/ROOT/lib’
mkdir: created directory ‘/appdata/webapps/ROOT/classes’
mkdir: created directory ‘/appdata/webapps/ROOT/WEB-INF’
[root@Tang-5 ~]# mkdir /appdata/webapps/test
3.2.2 创建相关文件
[root@Tang-5 ~]# cat /appdata/webapps/test/index.jsp
<%@ page language="java" %>
<html>
<head><title>TomcatB</title></head>
<body>
<h1><font color="blue">Tang-5</font></h1>
<table align="centre" border="1">
<tr>
<td>Session ID</td>
<% session.setAttribute("Tang","Tang"); %>
<td><%= session.getId() %></td>
</tr>
<tr>
<td>Created on</td>
<td><%= session.getCreationTime() %></td>
</tr>
</table>
</body>
</html>
[root@Tang-5 ~]# tree /appdata/webapps/
/appdata/webapps/
├── ROOT
│ ├── classes
│ ├── index.jsp
│ ├── lib
│ └── WEB-INF
└── test
└── index.jsp
5 directories, 2 files
3.2.3 修改 Tomcat 配置文件，并重启服务
### 在 </Engine> </Engine> 之间添加一个 HOST ###
[root@Tang-5 ~]# vim /etc/tomcat/server.xml
<Engine name="Catalina" defaultHost="localhost" jvmRoute="Tomcat-Tang-5">
<Host name="localhost" appBase="/appdata/webapps" unpackWARs="true" autoDeploy="true">
<Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
prefix="node1_access" suffix=".log"
pattern="%h %l %u %t "%r" %s %b" />
<Context path="/test" docBase="test" reloadable="">
<Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
prefix="Tang-5_access_" suffix=".log"
pattern="%h %l %u %t "%r" %s %b" />
</Context>
</Host>
<Engine>
[root@Tang-5 ~]# systemctl restart tomcat.service
3.2.4 修改 WIN7 HOSTS 文件，进行访问
3.2.5 查看相关 log
[root@Tang-5 ~]# tail /var/log/tomcat/Tang-5_test_access_2019-11-03.log
192.168.1.6 - - [03/Nov/2019:20:42:09 +0800] "GET /test/ HTTP/1.1" 200 322
192.168.1.6 - - [03/Nov/2019:20:42:13 +0800] "GET /test/ HTTP/1.1" 200 322
192.168.1.6 - - [03/Nov/2019:20:42:13 +0800] "GET /test/ HTTP/1.1" 200 322
192.168.1.6 - - [03/Nov/2019:20:42:14 +0800] "GET /test/ HTTP/1.1" 200 322
192.168.1.6 - - [03/Nov/2019:20:42:14 +0800] "GET /test/ HTTP/1.1" 200 322
192.168.1.6 - - [03/Nov/2019:20:42:14 +0800] "GET /test/ HTTP/1.1" 200 322
192.168.1.6 - - [03/Nov/2019:20:42:14 +0800] "GET /test/ HTTP/1.1" 200 322
192.168.1.6 - - [03/Nov/2019:20:42:14 +0800] "GET /test/ HTTP/1.1" 200 322
4、HTTPD Server 反代设置
4.1 conf 文件修改
[root@Tang-11 ~]# ipinfo
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.13 netmask 255.255.255.0 broadcast 192.168.1.255
--
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
[root@Tang-11 ~]# cat /etc/httpd/conf.d/tomcat.conf
<proxy balancer://tomcatservers>
BalancerMember ajp://192.168.1.11:8009 # 注意端口号，8009 是 AJP 使用的端口
BalancerMember ajp://192.168.1.12:8009
ProxySet lbmethod=byrequests
</Proxy>
<VirtualHost *:80>
ServerName www.neotang.com
ProxyVia On
ProxyRequests Off
ProxyPreserveHost Off
<Proxy *>
Require all granted
</Proxy>
ProxyPass / balancer://tomcatservers/
ProxyPassReverse / balancer://tomcatservers/
<Location />
Require all granted
</Location>
</VirtualHost>
4.2 conf 文件语法检查，并重启服务
[root@Tang-11 ~]# httpd -t
AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using fe80::20c:29ff:fee9:9f90. Set the 'ServerName' directive globally to suppress this message
Syntax OK
[root@Tang-11 ~]# systemctl restart httpd.service
4.3 修改 WIN7 主机的 HOSTS 文件
4.4 进行访问，通过刷新网页，可以看到在轮询访问后端 Tomcat 服务器
