1. Nginx介绍

Nginx是一款轻量级的Web服务器、反向代理服务器，由于它的内存占用少，启动极快，高并发能力强，在互联网项目中广泛应用。

上图基本上说明了当下流行的技术架构，其中Nginx有点入口网关的味道。

说了这么多，我们先安装玩玩吧

2. 安装Nginx

一般都是项目都是部署在linux上，这里我们采用Docker的方式启动Nginx，关于Docker的，上一篇有详细介绍

Docker

下面记录centos7利用Docker安装Nginx的命令

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[root@hspEdu01 nginx]# docker pull nginx
Using default tag: latest
Trying to pull repository docker.io/library/nginx ... 
latest: Pulling from docker.io/library/nginx
69692152171a: Already exists 
30afc0b18f67: Pull complete 
596b1d696923: Pull complete 
febe5bd23e98: Pull complete 
8283eee92e2f: Pull complete 
351ad75a6cfa: Pull complete 
Digest: sha256:6d75c99af15565a301e48297fa2d121e15d80ad526f8369c526324f0f7ccb750
Status: Downloaded newer image for docker.io/nginx:latest
[root@hspEdu01 nginx]# ls
conf  logs  www
[root@hspEdu01 nginx]# cd conf/
[root@hspEdu01 conf]# ls
nginx.conf
[root@hspEdu01 conf]# cd ../
[root@hspEdu01 nginx]# cd ../
[root@hspEdu01 ~]# rm -rf nginx/
[root@hspEdu01 ~]# ls
anaconda-ks.cfg  data  data2  initial-setup-ks.cfg  mysql  公共  模板  视频  图片  文档  下载  音乐  桌面
[root@hspEdu01 ~]# docker run --name nginx-test -p 80:80 -d nginx
608ed67163e091695eb14f964cff6f4d24f2818275845f34254eff49e24fe770
[root@hspEdu01 ~]# docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                           
608ed67163e0        nginx               "/docker-entrypoin..."   4 seconds ago       Up 2 seconds        0.0.0.0:80->80/tcp              
760a2956258e        a8e34               "java -jar app.jar"      About an hour ago   Up About an hour    0.0.0.0:8010->8010/tcp          
95628d5d89c5        mysql:5.7           "docker-entrypoint..."   About an hour ago   Up About an hour    0.0.0.0:3306->3306/tcp, 33060/tc
[root@hspEdu01 ~]# mkdir -p /root/nginx/www /root/nginx/logs /root/nginx/conf
[root@hspEdu01 ~]# cd nginx/
[root@hspEdu01 nginx]# cd conf/
[root@hspEdu01 conf]# ls
[root@hspEdu01 conf]# docker cp 608e:/etc/nginx/nginx.conf /root/nginx/conf
[root@hspEdu01 conf]# ls
nginx.conf
[root@hspEdu01 conf]# docker rm -f 608e
608e
[root@hspEdu01 conf]# docker run -d -p 80:80 --name nginx-web -v /root/nginx/www:/usr/share/nginx/html -v /root/nginx/conf/nginx.conf:/etc/nginx/nginx.conf -v /root/nginx/logs:/var/log/nginx nginx
987bc07bc4eb474332766dfe6409d957e07bf94fc24153222cf8bf99147df717
[root@hspEdu01 conf]# docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS                     PORTS                               NAMES
987bc07bc4eb        nginx               "/docker-entrypoin..."   10 seconds ago      Exited (1) 9 seconds ago                                       nginx-web
760a2956258e        a8e34               "java -jar app.jar"      About an hour ago   Up About an hour           0.0.0.0:8010->8010/tcp              adoring_pare
95628d5d89c5        mysql:5.7           "docker-entrypoint..."   About an hour ago   Up About an hour           0.0.0.0:3306->3306/tcp, 33060/tcp   mysql
[root@hspEdu01 conf]# docker logs -f 987b
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
10-listen-on-ipv6-by-default.sh: info: Getting the checksum of /etc/nginx/conf.d/default.conf
10-listen-on-ipv6-by-default.sh: info: Enabled listen on IPv6 in /etc/nginx/conf.d/default.conf
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh
/docker-entrypoint.sh: Configuration complete; ready for start up
nginx: [alert] could not open error log file: open() "/var/log/nginx/error.log" failed (13: Permission denied)
2021/06/12 02:26:39 [emerg] 1#1: open() "/etc/nginx/nginx.conf" failed (13: Permission denied)
[root@hspEdu01 conf]# docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED              STATUS                          PORTS                               NAMES
987bc07bc4eb        nginx               "/docker-entrypoin..."   About a minute ago   Exited (1) About a minute ago                                       nginx-web
760a2956258e        a8e34               "java -jar app.jar"      About an hour ago    Up About an hour                0.0.0.0:8010->8010/tcp              adoring_pare
95628d5d89c5        mysql:5.7           "docker-entrypoint..."   About an hour ago    Up About an hour                0.0.0.0:3306->3306/tcp, 33060/tcp   mysql
[root@hspEdu01 conf]# docker rm -f 987
987
[root@hspEdu01 conf]# docker run -d -p 80:80 --name nginx-web -v /root/nginx/www:/usr/share/nginx/html -v /root/nginx/conf/nginx.conf:/etc/nginx/nginx.conf -v /root/nginx/logs:/var/log/nginx --privileged=true nginx
6593ed8866071e1865217f58c627005aa8f3e9b3c8db6f5ff1aec22653503d1a
[root@hspEdu01 conf]# docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                               NAMES
6593ed886607        nginx               "/docker-entrypoin..."   5 seconds ago       Up 3 seconds        0.0.0.0:80->80/tcp                  nginx-web
760a2956258e        a8e34               "java -jar app.jar"      About an hour ago   Up About an hour    0.0.0.0:8010->8010/tcp              adoring_pare
95628d5d89c5        mysql:5.7           "docker-entrypoint..."   About an hour ago   Up About an hour    0.0.0.0:3306->3306/tcp, 33060/tcp   mysql
[root@hspEdu01 conf]# cd ../
[root@hspEdu01 nginx]# cd www/
[root@hspEdu01 www]# touch a.html
[root@hspEdu01 www]# vim a.html
[root@hspEdu01 www]#

这里我们创建了一个nginx-web的容器，并把它的网页目录，日志目录和配置文件目录挂载到宿主机，新建了一个a.html，因为Nginx的热部署的，所以我们直接在浏览器请求a.html即可

3. 负载均衡

在第二张图上，已经提到Nginx可以实现负载均衡，什么叫负载均衡呢？

如果请求数过大，单个服务器解决不了，我们增加服务器的数量，然后将请求分发到各个服务器上，将原先请求集中到单个服务器的情况改为请求分发到多个服务器上，就是负载均衡。

实现方式也很简单，在nginx.conf中upstream 指定后端服务器地址列表，在 server 中拦截响应请求，并将请求转发到 Upstream 中配置的服务器列表。

1. 轮询

这里我们利用Docker多端口启动3台Tomcat服务器，里面Nginx实现请求的负载均衡，下面记录详细命令：

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[root@VM-0-15-centos conf]# docker run -p 8010:8080 -v /root/tomcat8010/webapps:/usr/local/tomcat/webapps -d --name tomcat8081 bcf990bea01a
a386923c309b971e5c09c1656f706313d074d62f1a898844513594f662463c07
#三台Tomcat启动方式都是一样的 只是参数和数据卷不一样而已，这里以最后一台为例子
[root@VM-0-15-centos conf]# docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                               NAMES
a386923c309b        bcf990bea01a        "catalina.sh run"        4 seconds ago       Up 3 seconds        0.0.0.0:8010->8080/tcp              tomcat8081
5dbbb4db6e00        bcf990bea01a        "catalina.sh run"        20 hours ago        Up 20 hours         0.0.0.0:8881->8080/tcp              tomcat-8881
216a2e8f1c90        bcf990bea01a        "catalina.sh run"        20 hours ago        Up 20 hours         0.0.0.0:8888->8080/tcp              tomcat-8888
8499b0e39d0f        bcf990bea01a        "catalina.sh run"        21 hours ago        Up 21 hours         0.0.0.0:8080->8080/tcp              mytomcat
7dd71eee737f        mysql:5.7           "docker-entrypoint..."   43 hours ago        Up 43 hours         0.0.0.0:3306->3306/tcp, 33060/tcp   mysql
52aa02d195d9        nginx               "/docker-entrypoin..."   2 days ago          Up 2 minutes        0.0.0.0:80->80/tcp                  nginx-web
[root@VM-0-15-centos conf]# cd /root
[root@VM-0-15-centos ~]# ls
aa.txt  apps  data  demo  dockerfile  images  meiyan  mysql  nginx  RUNNING.txt  test  tomcat8010  tomcat-8881  tomcat8888  webapps
[root@VM-0-15-centos ~]# cd tomcat8010
[root@VM-0-15-centos tomcat8010]# ls
webapps
[root@VM-0-15-centos tomcat8010]# cd webapps
[root@VM-0-15-centos webapps]# mkdir edu
[root@VM-0-15-centos webapps]# cd edu
[root@VM-0-15-centos edu]# ouch a.html
-bash: ouch: command not found
[root@VM-0-15-centos edu]# touch a.html
[root@VM-0-15-centos edu]# vim a.html 
[root@VM-0-15-centos edu]# cat a.html 
<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<h3>Tomcat8010</h3>
	</body>
</html>

[root@VM-0-15-centos edu]# cd /root/nginx/conf/
[root@VM-0-15-centos conf]# vim nginx.conf 
#配置完nginx.conf 记得重启nginx服务
[root@VM-0-15-centos conf]# docker restart nginx-web
nginx-web
[root@VM-0-15-centos conf]#

这时候，我们可以在浏览器中访问http://118.195.164.41/edu/a.html，会发现它是跳转到不同的Tomcat上，即实现了负载均衡，这里只是第一种，我们并没设计细则，下面我们再展示讲述下其它几种：

2. 优先级

修改nginx.conf即可

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[root@VM-0-15-centos conf]# cat nginx.conf 

user  nginx;
worker_processes  auto;

error_log  /var/log/nginx/error.log notice;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/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  /var/log/nginx/access.log  main;
  upstream myserver {
	server 118.195.164.41:8080 weight=1;
	server 118.195.164.41:8888 weight=10;
	server 118.195.164.41:8881 weight=15;
	server 118.195.164.41:8010 weight=20;
   }


  server{
       listen 80;
       charset utf-8;
       server_name 118.195.164.41;
 

       location / {
          proxy_pass http://myserver;
       }
    }
    sendfile        on;
    #tcp_nopush     on;

    keepalive_timeout  65;

    #gzip  on;

    include /etc/nginx/conf.d/*.conf;
}

3.ip_hash

每个请求按访问ip的hash结果分配，这样每个访客固定访问一个后端服务器，可以解决session的问题。

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[root@VM-0-15-centos conf]# cat nginx.conf 

user  nginx;
worker_processes  auto;

error_log  /var/log/nginx/error.log notice;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/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  /var/log/nginx/access.log  main;
  upstream myserver {
	ip_hash;
	server 118.195.164.41:8080 ;
	server 118.195.164.41:8888 ;
	server 118.195.164.41:8881 ;
	server 118.195.164.41:8010 ;
   }


  server{
       listen 80;
       charset utf-8;
       server_name 118.195.164.41;
 

       location / {
          proxy_pass http://myserver;
       }
    }
    sendfile        on;
    #tcp_nopush     on;

    keepalive_timeout  65;

    #gzip  on;

    include /etc/nginx/conf.d/*.conf;
}

4.fair(第三方)

按后端服务器的响应时间来分配请求，响应时间短的优先分配。

需要安装其它依赖，这里就不测试了

4. 反向代理

经常听人说到一些术语，如反向代理，那么什么是反向代理，什么又是正向代理呢？

​ 正向代理示意图

​ 反向代理示意图

由于防火墙的原因，我们并不能直接访问谷歌，那么我们可以借助VPN来实现，这就是一个简单的正向代理的例子。这里你能够发现，正向代理“代理”的是客户端，而且客户端是知道目标的，而目标是不知道客户端是通过VPN访问的。

当我们在外网访问百度的时候，其实会进行一个转发，代理到内网去，这就是所谓的反向代理，即反向代理“代理”的是服务器端，而且这一个过程对于客户端而言是透明的。

Nginx实现反向代理是很容易的，下面记录详细命令：

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[root@VM-0-15-centos conf]# docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                               NAMES
a386923c309b        bcf990bea01a        "catalina.sh run"        22 hours ago        Up 22 hours         0.0.0.0:8010->8080/tcp              tomcat8081
5dbbb4db6e00        bcf990bea01a        "catalina.sh run"        42 hours ago        Up 42 hours         0.0.0.0:8881->8080/tcp              tomcat-8881
216a2e8f1c90        bcf990bea01a        "catalina.sh run"        43 hours ago        Up 43 hours         0.0.0.0:8888->8080/tcp              tomcat-8888
8499b0e39d0f        bcf990bea01a        "catalina.sh run"        43 hours ago        Up 43 hours         0.0.0.0:8080->8080/tcp              mytomcat
7dd71eee737f        mysql:5.7           "docker-entrypoint..."   2 days ago          Up 2 days           0.0.0.0:3306->3306/tcp, 33060/tcp   mysql
52aa02d195d9        nginx               "/docker-entrypoin..."   2 days ago          Up 39 seconds       0.0.0.0:80->80/tcp                  nginx-web
[root@VM-0-15-centos conf]# vim nginx.conf 
[root@VM-0-15-centos conf]# cat nginx.conf 

user  nginx;
worker_processes  auto;

error_log  /var/log/nginx/error.log notice;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/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  /var/log/nginx/access.log  main;
  upstream myserver {
	server 118.195.164.41:8080 ;
	server 118.195.164.41:8888 ;
	server 118.195.164.41:8881 ;
	server 118.195.164.41:8010 ;
	}

  server{
       listen 80;
       charset utf-8;
       server_name 118.195.164.41;
 

       location / {
          proxy_pass http://118.195.164.41:8888/edu/a.html;
	  	  proxy_redirect default;
       }
    }
    sendfile        on;
    #tcp_nopush     on;

    keepalive_timeout  65;

    #gzip  on;

    include /etc/nginx/conf.d/*.conf;
}
[root@VM-0-15-centos conf]# docker restart nginx-web
nginx-web
[root@VM-0-15-centos conf]# vim nginx.conf 
[root@VM-0-15-centos conf]# docker restart nginx-web
nginx-web
[root@VM-0-15-centos conf]#

使用方向代理，让访问80端口的请求重定向到8888端口下的一个页面，测试成功！

关于location的配置，主要就是对访问路径进行设置，有很多，下面这篇博文讲的很好：

nginx的location配置详解

5. 动静分离

Nginx 动静分离简单来说就是把动态跟静态请求分开，不能理解成只是单纯的把动态页面和静态页面物理分离。严格意义上说应该是动态请求跟静态请求分开，可以理解成使用 Nginx处理静态页面，Tomcat 处理动态页面。动静分离从目前实现角度来讲大致分为两种，一种是纯粹把静态文件独立成单独的域名，放在独立的服务器上，也是目前主流推崇的方案；

另外一种方法就是动态跟静态文件混合在一起发布，通过 nginx 来分开。通过 location 指定不同的后缀名实现不同的请求转发。通过 expires 参数设置，可以使浏览器缓存过期时间，减少与服务器之前的请求和流量。具体 Expires 定义：是给一个资源设定一个过期时间，也就是说无需去服务端验证，直接通过浏览器自身确认是否过期即可，

所以不会产生额外的流量。此种方法非常适合不经常变动的资源。（如果经常更新的文件，不建议使用 Expires 来缓存），我这里设置 3d，表示在这 3 天之内访问这个 URL，发送一个请求，比对服务器该文件最后更新时间没有变化，则不会从服务器抓取，返回状态码 304，如果有修改，则直接从服务器重新下载，返回状态码 200。

对于这个配置，其实就是在location配置下路径，但我一直没成功，不知道为什么！！配置如下：

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user  nginx;
worker_processes  auto;

error_log  /var/log/nginx/error.log notice;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/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"';

 upstream static {
	server 118.195.164.41:80;
      } 

  upstream dynamic {
	server 118.195.164.41:8080 ;
#	server 118.195.164.41:8888 ;
#	server 118.195.164.41:8881 ;
#	server 118.195.164.41:8010 ;
      }	

  server{
       listen 80;
       charset utf-8;
       server_name 118.195.164.41;
       
       
          # 拦截动态资源
    location ~ .*\.(php|jsp)$ {
       proxy_pass http://dynamic;
    }
   
    # 拦截静态资源
    location ~ .*\.(jpg|png|htm|html|css|js)$ {       
       root /data/;  #html目录
       proxy_pass http://static;
       autoindex on;  #自动打开文件列表
    }  

    }
    sendfile        on;
    #tcp_nopush     on;

    keepalive_timeout  65;

    #gzip  on;

    include /etc/nginx/conf.d/*.conf;
}

后面有时间再更新Nginx的~

6. 参考文章

8分钟带你深入浅出搞懂Nginx