反向代理：

目的：

访问http://192.168.111.144跳转到tomcat

向192.168.111.145虚拟机中安装tomcat，去tomcat官网拉一个tomcat的包，然后解压,进入/bin目录，执行命令./startup.sh?就开启了tomcat

这样就ok了

向192.168.111.144虚拟机中安装nginx，因为我的是ubuntu20.04系统，我直接下载就行

apt -y install nginx

然后进入/etc/nginx/sites-available文件夹中配置default文件，配置如下。

root@apang:/etc/nginx/sites-available# cat default 
##
# You should look at the following URL's in order to grasp a solid understanding
# of Nginx configuration files in order to fully unleash the power of Nginx.
# https://www.nginx.com/resources/wiki/start/
# https://www.nginx.com/resources/wiki/start/topics/tutorials/config_pitfalls/
# https://wiki.debian.org/Nginx/DirectoryStructure
#
# In most cases, administrators will remove this file from sites-enabled/ and
# leave it as reference inside of sites-available where it will continue to be
# updated by the nginx packaging team.
#
# This file will automatically load configuration files provided by other
# applications, such as Drupal or Wordpress. These applications will be made
# available underneath a path with that package name, such as /drupal8.
#
# Please see /usr/share/doc/nginx-doc/examples/ for more detailed examples.
##

# Default server configuration
#
server {
	listen 80 default_server;
	listen [::]:80 default_server;

	# SSL configuration
	#
	# listen 443 ssl default_server;
	# listen [::]:443 ssl default_server;
	#
	# Note: You should disable gzip for SSL traffic.
	# See: https://bugs.debian.org/773332
	#
	# Read up on ssl_ciphers to ensure a secure configuration.
	# See: https://bugs.debian.org/765782
	#
	# Self signed certs generated by the ssl-cert package
	# Don't use them in a production server!
	#
	# include snippets/snakeoil.conf;

	#root /var/www/html;

	# Add index.php to the list if you are using PHP
	#index index.html index.htm index.nginx-debian.html;

	#server_name _;

	location / {
		# First attempt to serve request as file, then
		# as directory, then fall back to displaying a 404.
		#try_files $uri $uri/ =404;
		proxy_pass http://192.168.111.145:8080;
	}
	#location /tomcat {
	#	proxy_pass http://192.168.111.145:8080;
	#	index index.html index.htm;
	#}

	# pass PHP scripts to FastCGI server
	#
	#location ~ \.php$ {
	#	include snippets/fastcgi-php.conf;
	#
	#	# With php-fpm (or other unix sockets):
	#	fastcgi_pass unix:/run/php/php7.4-fpm.sock;
	#	# With php-cgi (or other tcp sockets):
	#	fastcgi_pass 127.0.0.1:9000;
	#}

	# deny access to .htaccess files, if Apache's document root
	# concurs with nginx's one
	#
	#location ~ /\.ht {
	#	deny all;
	#}
}


# Virtual Host configuration for example.com
#
# You can move that to a different file under sites-available/ and symlink that
# to sites-enabled/ to enable it.
#
#server {
#	listen 80;
#	listen [::]:80;
#
#	server_name example.com;
#
#	root /var/www/example.com;
#	index index.html;
#
#	location / {
#		try_files $uri $uri/ =404;
#	}
#}

?然后我们用我们的真机去访问192.168.111.144，发现已经转发了

?顺便说一下正向代理和反向代理。

正向代理就像我们经常用的VPN技术一样。我们可以更换我们的代理点，从而访问到我们想要访问的资源。

反向代理就是我们访问一台服务器，而这台服务器只不过是一个代理点，会转发到我们真正想要访问的资源，如同上面操作一样。

简单来说，正向代理就是需要我们去更换代理点的，而反向代理你是根本就没察觉的。

负载均衡：

希望在操作之前将默认的要修改的配置文件都备份一下，养成好习惯。

环境：

ubuntu04	192.168.111.144	nginx
ubuntu05	192.168.111.145	tomcat
rooky06	192.168.111.111	tomcat

修改一下tomcat默认的页面进行辨别。

默认页面在这里

?修改为这样：

?配置ubuntu04上面的nginx的配置文件，我的是ubuntu系统，其他系统可能不一样，但是应该大差不差。

在/etc/nginx/conf.d下创建一个以 .conf 为后缀的文件。我这里创建的是tomcat.conf?

?配置如下：

upstream tomcat {
        #负载均衡方法，可以自己选，默认为轮询方式
        #服务器的访问方式，
        server 192.168.111.145:8080 weight=1;
        server 192.168.111.111:8080 weight=1;
}

server {
        #负载均衡监视的端口
        listen 81 default_server;
        listen [::]:81 default_server;
        #负载均衡服务器的名称，没有的话填_
        server_name _;
        location / {
                #代理转发，注意这个tomcat要与上面的upstream后面的字符一样
                proxy_pass http://tomcat;
        }
}

后面的数值为权重，我是两台服务器，如果那个性能好的话，我们可以将权重相对来说调的大些。

重启nginx。

访问http://192.168.111.144:81