Nginx：一款高性能的反向代理服务器

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Nginx 是什么？

Nginx™ [engine x] is an HTTP and reverse proxy server, a mail proxy server, and a generic TCP/UDP proxy server

环境搭建

下载

　在 Nginx Archive 下载页面，下载 nginx-1.13.12.tar.gz 安装包

安装依赖

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$ yum -y install openssl openssl-devel
$ yum -y install pcre-devel

编译安装

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$ tar zxvf nginx-1.13.12.tar.gz
# 必须要跳转到 nginx 安装目录下
$ cd nginx-1.13.12
$ ./configure --prefix=/usr/local/nginx --conf-path=/usr/local/nginx/nginx.conf
$ make -j4 && make -j4 install

启动

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$ cd /usr/local/nginx/
$ sbin/nginx -c /usr/local/nginx/nginx.conf
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$ ps -ef | grep nginx
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root     107034      1  0 Oct31 ?        00:00:00 nginx: master process sbin/nginx
nobody   107036 107034  0 Oct31 ?        00:00:00 nginx: worker process
nobody   107266 107265  0 Oct31 ?        00:00:00 tsar --check --apache --cpu --mem --load --io --traffic --tcp --partition --nginx --swap
root     107270  97588  0 Oct31 pts/1    00:00:00 grep nginx

停止

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$ sbin/nginx -s stop

校验

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$ curl localhost
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<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

修改配置文件

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$ vim nginx.conf

重新加载配置文件

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$ sbin/nginx -s reload

查看日志

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# 查看流量详情
$ tail -f logs/access.log

# 查看异常日志
$ tail -f logs/error.log

流量镜像

Upstream 模块

　通过 upstream 模块，可以将源地址（当前集群）和镜像地址（目标集群）分组

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upstream curr {
    server 192.168.0.101:8080;
    server 192.168.0.102:8080;
    keepalive 64;
}

upstream dest {
    server 192.168.0.103:8080;
    server 192.168.0.104:8080;
    keepalive 64;
}

Server 模块

　如下定义了当前 Nginx 进程（localhost）监听的端口（80）

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server {
    listen         80;
    server_name    localhost;
    # ...
}
注意观察 logs/error.log 日志，检查是否出现端口冲突的日志，以调整这里面的端口号

Location 模块

　server 模块下的 location 模块，可以定义流量转发的规则，location / 会接受所有 Nginx 进来的流量，而 mirror /mirror; 会将流量转发到镜像地址，而 location /mirror 则定义了转发的规则

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location / {
    root   html;
    index  index.html index.htm;
    mirror /mirror;
    mirror_request_body on;
    proxy_pass http://curr;
}

location /mirror {
    internal;
    proxy_pass http://dest$request_uri;
    proxy_set_header X-Original-URI $request_uri;
}

完整示例

本地转发

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#user              nginx;
worker_processes  auto;

#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;

    keepalive_timeout   65;

    upstream curr {
        server localhost:8080;
        keepalive 64;
    }

    server {
        listen         80;
        server_name    localhost;

        #charset koi8-r;

        #access_log    logs/host.access.log  main;

        location / {
            root   html;
            index  index.html index.htm;
            mirror_request_body on;
            proxy_pass http://curr;
        }

        error_page     500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }
    }
}

集群间转发

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#user              nginx;
worker_processes  auto;

#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;

    keepalive_timeout   65;

    upstream curr {
        server 192.168.0.101:8080;
        server 192.168.0.102:8080;
        keepalive 64;
    }

    upstream dest {
        server 192.168.0.103:8080;
        server 192.168.0.104:8080;
        keepalive 64;
    }

    server {
        listen         80;
        server_name    localhost;

        #charset koi8-r;

        #access_log    logs/host.access.log  main;

        location / {
            root   html;
            index  index.html index.htm;
            mirror /mirror;
            mirror_request_body on;
            proxy_pass http://curr;
        }

        location /mirror {
            internal;
            proxy_pass http://dest$request_uri;
            proxy_set_header X-Original-URI $request_uri;
        }

        error_page     500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }
    }
}

轮询策略

RR

　按时间顺序逐一将请求发送到不同的服务器，并且服务器故障后，会被自动剔除

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upstream yuzhouwan {
  server 192.168.0.101:80 max_fails=3 fail_timeout=3s weight=9;
  server 192.168.0.102:80 max_fails=3 fail_timeout=3s weight=9;
}
Nginx 默认会采用 RR（round-robin）简单轮询策略

balance

　支持指定轮询的几率，参数 weight 的数值和访问几率成正比，常用于集群中服务器资源不均的场景

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upstream yuzhouwan {
  server 192.168.0.101:80 weight=6;
  server 192.168.0.102:80 weight=1;
}

ip_hash

　按访问 ip 的 hash 结果将请求发送到不同的服务器，这样每个访客固定访问一个后端服务器。可以在 Session 有状态情况下，避免请求被转发到不同的服务器后，需要重复登录的问题

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upstream yuzhouwan {
  ip_hash;
  server 192.168.0.101:80;
  server 192.168.0.102:80;
}

fair

　按服务器的响应时间来分配请求，响应时间短的优先分配

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upstream yuzhouwan {
  fair;
  server 192.168.0.101:80;
  server 192.168.0.102:80;
}

url_hash

　按访问 url 的 hash 结果来分配请求，可以充分发挥服务器上缓存的作用

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upstream yuzhouwan {
  hash $request_uri;
  hash_method crc32;
  server 192.168.0.101:80;
  server 192.168.0.102:80;
}

踩过的坑

client intended to send too large body

分析

　Nginx 默认不允许发送超过 1MB 的请求体，由 client_max_body_size 参数控制

解决

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$ vim nginx.conf
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http {
  client_max_body_size 10M;
  # ...
}
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$ sbin/nginx -s reload

补充

参数名 含义 默认值 作用域
chunked_transfer_encoding 是否开启 HTTP/1.1 下的 chunked 编码 on http, server, location
client_header_buffer_size 请求头的大小限制 1k http, server
client_body_timeout 读取请求体的超时限制 60s http, server, location

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