实现Nginx+Tomcat负载均衡

1、环境：

1、操作系统：Centos7.6

2、服务器配置如下：

服务器	软件
182.92.220.145	Nginx
123.206.63.55	Tomcat
132.232.125.97	Tomcat

2、安装Nginx

2.1 下载

`进入到/usr/local/src目录下`
[[e-mail] ~]# cd /usr/local/src

`下载nginx`
[[e-mail] src]# wget http://nginx.org/download/nginx-1.16.1.tar.gz

`解压缩`
[[e-mail] src]# tar -zxvf nginx-1.16.1.tar.gz

2.2安装

`进入到/usr/local/src/nginx-1.16.1目录中`
[[e-mail] nginx-1.16.1]# cd /usr/local/src/nginx-1.16.1
[[e-mail] nginx-1.16.1]# ./configure --prefix=/usr/local/nginx

`编译安装`
[[e-mail] nginx-1.16.1]# make && make install

编译过程中可能会出现如下常见问题：

1、缺少PCRE

`-------错误信息---------------`
./configure: error: the HTTP rewrite module requires the PCRE library.
You can either disable the module by using --without-http_rewrite_module
option, or install the PCRE library into the system, or build the PCRE library
statically from the source with nginx by using --with-pcre=<path> option.
  
`----- ---解决方案--------------------`
  yum -y install pcre-devel

2、缺少zlib

`--------错误信息---------------`
./configure: error: the HTTP gzip module requires the zlib library.
You can either disable the module by using --without-http_gzip_module
option, or install the zlib library into the system, or build the zlib library
statically from the source with nginx by using --with-zlib=<path> option.

`-------解决方案--------------------`
yum -y install zlib-devel

2.3 启动nginx

`启动nginx服务`
[[e-mail] nginx]# cd /usr/local/nginx/sbin
[[e-mail] sbin]# ./nginx
`查看nginx启动情况`
[[e-mail] sbin]# ps -ef|grep nginx
root     16374     1  0 23:12 ?        00:00:00 nginx: master process ./nginx
nobody   16375 16374  0 23:12 ?        00:00:00 nginx: worker process
root     16377 11301  0 23:12 pts/0    00:00:00 grep --color=auto nginx

2.4 防火墙

为方便测试，我直接关闭了防火墙，在实际应用中可以根据需要开启防火墙的端口，此外还要设置服务器的安全策略，我的是阿里云的服务器，就在阿里云服务器控制台设置了安全策略，开放了需要的端口。

• 关闭防火墙：

`关闭防火墙`
[[e-mail] sbin]# systemctl stop firewalld

`查看防火墙状态`
[[e-mail] sbin]# systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
   Active: inactive (dead)
     Docs: man:firewalld(1)

Mar 07 22:39:08 henry003 systemd[1]: Starting firewalld - dynamic firewall daemon...
Mar 07 22:39:08 henry003 systemd[1]: Started firewalld - dynamic firewall daemon.
Mar 07 22:39:23 henry003 systemd[1]: Stopping firewalld - dynamic firewall daemon...
Mar 07 22:39:24 henry003 systemd[1]: Stopped firewalld - dynamic firewall daemon.

2.5 访问

访问后可以看到nginx熟悉的界面。

3 、Tomcat

tomcat安装就不在此介绍了，我已在另外两台服务器分别安装了tomcat。接下来就进行nginx的配置，来实现负载均衡。

4、配置nginx

4.1nginx配置文件

`进入到nginx配置目录下`
[[e-mail] conf]# cd /usr/local/nginx/conf
`编辑nginx.conf`
[[e-mail] conf]# vim nginx.conf

nginx.conf文件如下：

#user  nobody;
worker_processes  1;

#error_log  logs/error.log;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;

#pid        logs/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                     '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  logs/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;

	#引入文件
    include ../extra/*.conf;   
    gzip on;
    gzip_min_length 5k;
    gzip_comp_level 3;
    gzip_types application/javascript image/jpeg image/svg+xml image/png;
    gzip_buffers 4 32k;
    gzip_vary on;

}

4.2 外链一个配置文件

创建extra文件夹，并创建文件tomcat.conf

[[e-mail] nginx]# mkdir /usr/local/nginx/extra
[[e-mail] nginx]# cd extra/
[[e-mail] nginx]# vim tomcat.conf

tomcat.conf文件如下：

upstream tomcat {
    server 123.206.63.55:8090 max_fails=2 fail_timeout=60s;
    server 132.232.125.97:8090;
}
server {
    listen 80;
    server_name localhost;
    location / {
        proxy_pass http://tomcat;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_next_upstream error timeout http_500 http_503;
        proxy_connect_timeout 60s;
        proxy_send_timeout 60s;
        proxy_read_timeout 60s;
        add_header 'Access-Control-Allow-Origin' '*';
        add_header 'Access-Control-Allow-Methods' 'GET,POST,DELETE';
        add_header 'Aceess-Control-Allow-Header' 'Content-Type,*';
	}
	#location ~ .*\.(js|css|png|svg|ico|jpg)$ {
		#防盗链
    #    valid_referers none blocked 123.206.63.55;
    #    if ($invalid_referer) {
    #    return 404;
    #    }
    #    root static-resource;
    #    expires 1d;
	#}
}

5、访问

为了区分两个tomcat，修改了其中一个tomcat的首页：

• 访问Nginx地址

再次刷新页面，可以访问到另外一个Tomcat：

结语：

到此nginx的配置就已经完成了，要想了解LVS+KeepAlived+Nginx+Tomcat高可用解决方案，可以访问以下地址。
LVS+KeepAlived+Nginx+Tomcat高可用解决方案https://blog.csdn.net/qq_33996921/article/details/105000294