Nginx + Tomcat 实现负载均衡
1、实验拓扑
2、各个虚机的软件安装
2.1 Nginx Server
2.1.1 Nginx 安装
[root@Tang-7 ~]# ipinfo
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.10 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-7 ~]# yum install nginx -y
2.1.2 Nginx 启动
[root@Tang-7 ~]# systemctl start nginx.service
[root@Tang-7 ~]# ss -tnl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 *:80 *:*
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 Nginx 访问
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、Nginx Server 反代设置
4.1 conf 文件修改
[root@Tang-7 ~]# ipinfo
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.10 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-7 ~]# vim /etc/nginx/nginx.conf
http {
upstream tomcatservers {
server 192.168.1.11:8080;
server 192.168.1.12:8080;
}
server {
listen 80 default_server;
listen [::]:80 default_server;
server_name _;
index index.jsp index.html;
location / {
root /usr/share/nginx/html;
}
location /test/ {
proxy_pass http://tomcatservers;
}
}
}
4.2 conf 文件语法检查，并重启服务
[root@Tang-7 ~]# nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
[root@Tang-7 ~]# nginx -s reload
4.3 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
4.4 后端 Tomcat 服务器 log 查看
[root@Tang-6 ~]# 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-6 ~]# tail /var/log/tomcat/Tang-6_test_access_2019-11-03.log
192.168.1.10 - - [03/Nov/2019:21:19:19 +0800] "GET /test/ HTTP/1.1" 200 321
192.168.1.6 - - [03/Nov/2019:21:19:34 +0800] "GET /test HTTP/1.1" 302 -
192.168.1.6 - - [03/Nov/2019:21:19:34 +0800] "GET /test/ HTTP/1.1" 200 321
192.168.1.6 - - [03/Nov/2019:21:28:31 +0800] "GET /test/ HTTP/1.1" 200 321
192.168.1.6 - - [03/Nov/2019:21:28:31 +0800] "GET /test/ HTTP/1.1" 200 321
192.168.1.6 - - [03/Nov/2019:21:28:31 +0800] "GET /test/ HTTP/1.1" 200 321
192.168.1.6 - - [03/Nov/2019:21:28:32 +0800] "GET /test/ HTTP/1.1" 200 321
192.168.1.10 - - [03/Nov/2019:21:30:35 +0800] "GET /test/ HTTP/1.1" 200 321
192.168.1.6 - - [03/Nov/2019:21:48:50 +0800] "GET /test/ HTTP/1.1" 200 321
192.168.1.10 - - [03/Nov/2019:21:54:35 +0800] "GET /test/ HTTP/1.1" 200 321
[root@Tang-5 ~]# 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-5 ~]# tail /var/log/tomcat/Tang-5_test_access_2019-11-03.log
192.168.1.10 - - [03/Nov/2019:21:29:44 +0800] "GET /test/ HTTP/1.1" 200 322
192.168.1.10 - - [03/Nov/2019:21:30:21 +0800] "GET /test/ HTTP/1.1" 200 322
192.168.1.6 - - [03/Nov/2019:21:31:29 +0800] "GET /test/ HTTP/1.1" 200 322
192.168.1.6 - - [03/Nov/2019:21:31:30 +0800] "GET /test/ HTTP/1.1" 200 322
192.168.1.6 - - [03/Nov/2019:21:48:52 +0800] "GET /test/ HTTP/1.1" 200 322
192.168.1.6 - - [03/Nov/2019:21:48:52 +0800] "GET /test/ HTTP/1.1" 200 322
192.168.1.6 - - [03/Nov/2019:21:48:52 +0800] "GET /test/ HTTP/1.1" 200 322
192.168.1.10 - - [03/Nov/2019:21:56:34 +0800] "GET /test/ HTTP/1.0" 200 322
192.168.1.10 - - [03/Nov/2019:22:02:32 +0800] "GET /test/ HTTP/1.0" 200 322
192.168.1.10 - - [03/Nov/2019:22:06:11 +0800] "GET /test/ HTTP/1.0" 200 322
5、注意事项（反代其它主机名失败的原因）
进行反代时，只能反代到后端 Tomcat 服务器的 localhost 上，如果反代到其它 主机名 的话，反代失败。提示 404 。
