[Linux Security Operation and Maintenance] Nginx related

2024-07-12

Nginx related

1 Overview

Nginx is a web server that has high concurrency and high load capabilities and has the following advantages:

Stable, consumes less system resources and occupies less memory.
The software installation package is small and highly customizable.
It has high concurrency capability and can handle 30,000-50,000 requests.

As a web server for static pages, Nginx mainly considers its performance and pays great attention to efficiency.

Configuration file (the most basic configuration file):

The configuration file is mainly divided into three blocks: global block, events block and http block.

# 全局块
worker_processes  1;  
# 事件区块
events {
    worker_connections  1024;
}
# http区块
http {
    include       mime.types;
    default_type  application/octet-stream;
    sendfile        on;
    keepalive_timeout  65;
    server {
        listen       80;
        server_name  localhost; #改为IP地址
        # 反向代理
        location / {
            root   html; #存放目录
            index  index.html index.htm;
        }
        # 错误页面路由
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }
    }
}

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Global Block: Used to store the overall configuration of the niginx server, including the number of related processes, process ID, storage path, log storage path, user group and other information.

Events Block: Used to store the relevant configuration of niginx server and user connection.

http block: Used to store some server access control and third-party configurations, including http global blocks and server blocks.

2. Reverse Proxy

2.1 Reverse proxy related

When the client accesses, it can access without configuration. The reverse proxy server will receive the client's request, and then the reverse proxy server will select the access and return the acquired data to the client. The advantage of this is that using a reverse proxy server canHide the real server IP and expose the proxy server IP。

Configuration Files:

#接口端
location /police/ {
    proxy_pass   http://192.168.1.1:8852/police/;
    proxy_redirect default;
    proxy_http_version 1.1;
    proxy_connect_timeout   60;
    proxy_send_timeout      60;
    proxy_read_timeout      90;
}

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If you encounter an interface that starts with a /police request, visit http://192.168.1.1:8852/police/.

If you want to define a reverse proxy for multiple ports, you need to modify the proxy header (location /police/) and the accessed IP address (proxy_pass http://192.168.1.1:8852/police/;).

2.2 Forward Proxy

If users in a local area network want to access the Internet and access servers through a proxy server, a forward proxy server is required.

3. Load Balancing

Load balancing is achieved by changing the request from being sent to a single server to being sent to multiple servers.

#动态服务器组
upstream dynamic_zuoyu {
    server localhost:8080;  #tomcat 7.0
    server localhost:8081;  #tomcat 8.0
    server localhost:8082;  #tomcat 8.5
    server localhost:8083;  #tomcat 9.0
    }
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There are four basic methods to achieve load balancing: polling, weight mode, ip_hash, and least_conn.

method	explain
Polling	Default mode
weight	According to weight distribution
ip_hash	Based on IP allocation
least_conn	Allocate based on minimum connection time

3.1 Implementation

Polling method (default):

Each request is assigned to each server one by one in chronological order

#动态服务器组
upstream dynamic_zuoyu {
    server localhost:8080;  #tomcat 7.0
    server localhost:8081;  #tomcat 8.0
    server localhost:8082;  #tomcat 8.5
    server localhost:8083;  #tomcat 9.0
    	# server 参数
    	#fail_timeout 最大失败时间
    	#max_fails	设置在fail_timeout参数设置的时间内最大失败次数,超过则认为停机
    	#fail_time	服务器会被认为停机的时间长度,默认为10s
    	#backup	标记该服务器为备用服务器，当主服务器停止时，请求会被发送到它这里
    	#down	标记服务器永久停机
}
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weight (weighted round robin):

Specify the polling probability and control access through weight. The access ratio is proportional to the weight.

#动态服务器组
upstream dynamic_zuoyu {
    server localhost:8080   weight=2;  #tomcat 7.0
    server localhost:8081;  #tomcat 8.0
    server localhost:8082   backup;  #tomcat 8.5
    server localhost:8083   max_fails=3 fail_timeout=20s;  #tomcat 9.0
}
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ip_hash：

Requests are processed through a hash algorithm. When a user accesses a server again, it will be automatically located and each request will be assigned according to the hash result of the access IP, so that each user can access a fixed backend server.

#动态服务器组
upstream dynamic_zuoyu {
    ip_hash;    #保证每个访客固定访问一个后端服务器
    server localhost:8080   weight=2;  #tomcat 7.0
    server localhost:8081;  #tomcat 8.0
    server localhost:8082;  #tomcat 8.5
    server localhost:8083   max_fails=3 fail_timeout=20s;  #tomcat 9.0
}
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least_conn:

Forward the request to the backend server with fewer connections.

#动态服务器组
upstream dynamic_zuoyu {
    least_conn;    #把请求转发给连接数较少的后端服务器
    server localhost:8080   weight=2;  #tomcat 7.0
    server localhost:8081;  #tomcat 8.0
    server localhost:8082 backup;  #tomcat 8.5
    server localhost:8083   max_fails=3	fail_timeout=20s;  #tomcat 9.0
}
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4. Separation of static and dynamic

Dynamic pages and static pages are parsed by different servers.

Configuration Files:

#访问静态资源服务器
location /image/ {
  root   /var/filecenter/;
}
location /static/ {
  root   /var/filecenter/;
}
location /car/ {
  root   /var/filecenter/;
}
location ~ .*.(html|htm|gif|jpg|jpeg|bmp|png|ico|js|css)$ {
  root /Users/dalaoyang/Downloads/static;
}
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#动态页面访问后台服务
#接口端
        location /police/ {
            proxy_pass   http://192.168.1.1:8852/police/;
            proxy_redirect default;
            proxy_http_version 1.1;
            proxy_connect_timeout   60;
            proxy_send_timeout      60;
            proxy_read_timeout      90;
        }
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5. Common commands

yum install nginx	安装nginx
netstat -anput|grep nginx 查看nginx进程
netstat -nltp	查看服务器端口占用情况
cd /usr/local/nginx/sbin/
./nginx  启动
./nginx -s stop  停止
./nginx -s quit  安全退出
./nginx -s reload  重新加载配置文件  如果我们修改了配置文件，就需要重新加载。
ps aux|grep nginx  查看nginx进程
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6. Complete Configuration File


#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;

    #gzip  on;

    server {
        listen       80;
        server_name  localhost;

        #charset koi8-r;

        #access_log  logs/host.access.log  main;

        location / {
            root   html;
            index  index.html index.htm;
        }

        #error_page  404              /404.html;

        # redirect server error pages to the static page /50x.html
        #
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }

        # proxy the PHP scripts to Apache listening on 127.0.0.1:80
        #
        #location ~ .php$ {
        #    proxy_pass   http://127.0.0.1;
        #}

        # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
        #
        #location ~ .php$ {
        #    root           html;
        #    fastcgi_pass   127.0.0.1:9000;
        #    fastcgi_index  index.php;
        #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
        #    include        fastcgi_params;
        #}

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


    # another virtual host using mix of IP-, name-, and port-based configuration
    #
    #server {
    #    listen       8000;
    #    listen       somename:8080;
    #    server_name  somename  alias  another.alias;

    #    location / {
    #        root   html;
    #        index  index.html index.htm;
    #    }
    #}


    # HTTPS server
    #
    #server {
    #    listen       443 ssl;
    #    server_name  localhost;

    #    ssl_certificate      cert.pem;
    #    ssl_certificate_key  cert.key;

    #    ssl_session_cache    shared:SSL:1m;
    #    ssl_session_timeout  5m;

    #    ssl_ciphers  HIGH:!aNULL:!MD5;
    #    ssl_prefer_server_ciphers  on;

    #    location / {
    #        root   html;
    #        index  index.html index.htm;
    #    }
    #}

}


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