文章目录

前言
安装 nginx
查找nginx安装和配置文件的位置
修改配置文件
重启nginx服务
查看报错
负载均衡配置
- 轮询
- 权重
- 最少连接
- IP哈希
总结

前言

Nginx虽不是第一次接触，但是使用较少，今天算是完整的安装了配置了一次，前段时间想写一写的《Nginx的安装与常用配置》，因突发状况没有写完，今天补充一下。

安装 nginx

nginx 安装比较方便，我安装的环境是拥有root权限的Ubuntu 20.04，安装只需要以下两个命令：

apt update
apt install nginx

安装完默认启动，查询运行状态的命令 systemctl status nginx

# systemctl status nginx
● nginx.service - A high performance web server and a reverse proxy server
     Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
     Active: active (running) since Tue 2023-03-14 21:09:35 CST; 2h 55min ago
       Docs: man:nginx(8)
    Process: 943307 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=0/SUCCESS)
    Process: 943314 ExecStart=/usr/sbin/nginx -g daemon on; master_process on; (code=exited, status=0/SUCCESS)
   Main PID: 943315 (nginx)
      Tasks: 5 (limit: 9132)
     Memory: 10.6M
     CGroup: /system.slice/nginx.service
             ├─943315 nginx: master process /usr/sbin/nginx -g daemon on; master_process on;
             ├─943316 nginx: worker process
             ├─943317 nginx: worker process
             ├─943318 nginx: worker process
             └─943319 nginx: worker process

Mar 14 21:09:35 w-mi-dev systemd[1]: Starting A high performance web server and a reverse proxy server...
Mar 14 21:09:35 w-mi-dev snoopy[943307]: [hostname:w-mi-dev ssh:((undefined)) uid:0 username:root pid:943307 ppid:1 rpname:(nginx) sid:943307 tty:(none) cwd:/ filename:/usr/sbin/nginx]: /usr/sbin/ng>
Mar 14 21:09:35 w-mi-dev snoopy[943314]: [hostname:w-mi-dev ssh:((undefined)) uid:0 username:root pid:943314 ppid:1 rpname:(nginx) sid:943314 tty:(none) cwd:/ filename:/usr/sbin/nginx]: /usr/sbin/ng>
Mar 14 21:09:35 w-mi-dev systemd[1]: Started A high performance web server and a reverse proxy server.

要想测试的话通过浏览器访问 http://YOUR_IP，通常会看到 “Welcome to nginx” 字样的界面，但这对于我是没用的，我的默认端口访问不了。

查找nginx安装和配置文件的位置

我的nginx安装在 /usr/sbin/nginx 目录，配置文件主目录在 /etc/nginx/nginx.conf，找的方法比较简单就是用 which 命令

# which nginx
/usr/sbin/nginx

找配置文件时利用 nginx 检查配置文件的 -t 参数就可以了

# nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful

如果使用 which 命令找不到，可以利用 ps -ef | grep nginx 找到进程id，在利用 ll /proc/nginx_pid 来找到安装的位置。

修改配置文件

进入 /etc/nginx 目录，可以看到多个配置文件和目录

# cd /etc/nginx/
# ll
total 64
drwxr-xr-x 2 root root 4096 Mar 14 20:56 conf.d/
-rw-r--r-- 1 root root 1077 Feb  4  2019 fastcgi.conf
-rw-r--r-- 1 root root 1007 Feb  4  2019 fastcgi_params
-rw-r--r-- 1 root root 2837 Feb  4  2019 koi-utf
-rw-r--r-- 1 root root 2223 Feb  4  2019 koi-win
-rw-r--r-- 1 root root 3957 Feb  4  2019 mime.types
drwxr-xr-x 2 root root 4096 Nov 10 14:38 modules-available/
drwxr-xr-x 2 root root 4096 Mar  9 21:30 modules-enabled/
-rw-r--r-- 1 root root 1490 Feb  4  2019 nginx.conf
-rw-r--r-- 1 root root  180 Feb  4  2019 proxy_params
-rw-r--r-- 1 root root  636 Feb  4  2019 scgi_params
drwxr-xr-x 2 root root 4096 Mar  9 21:30 sites-available/
drwxr-xr-x 2 root root 4096 Mar  9 21:30 sites-enabled/
drwxr-xr-x 2 root root 4096 Mar  9 21:30 snippets/
-rw-r--r-- 1 root root  664 Feb  4  2019 uwsgi_params
-rw-r--r-- 1 root root 3071 Feb  4  2019 win-utf

其中 nginx.conf 是主配置文件，内容如下：

user www-data;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
    
    
        worker_connections 768;
        # multi_accept on;
}

http {
    
    

        ##
        # Basic Settings
        ##

        sendfile on;
        tcp_nopush on;
        tcp_nodelay on;
        keepalive_timeout 65;
        types_hash_max_size 2048;
        # server_tokens off;

        # server_names_hash_bucket_size 64;
        # server_name_in_redirect off;

        include /etc/nginx/mime.types;
        default_type application/octet-stream;

        ##
        # SSL Settings
        ##

        ssl_protocols TLSv1 TLSv1.1 TLSv1.2 TLSv1.3; # Dropping SSLv3, ref: POODLE
        ssl_prefer_server_ciphers on;

        ##
        # Logging Settings
        ##

        access_log /var/log/nginx/access.log;
        error_log /var/log/nginx/error.log;

        # Gzip Settings
        ##

        gzip on;

        # gzip_vary on;
        # gzip_proxied any;
        # gzip_comp_level 6;
        # gzip_buffers 16 8k;
        # gzip_http_version 1.1;
        # gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;

        ##
        # Virtual Host Configs
        ##

        include /etc/nginx/conf.d/*.conf;
        include /etc/nginx/sites-enabled/*;
}


#mail {
    
    
#       # See sample authentication script at:
#       # http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript
#
#       # auth_http localhost/auth.php;
#       # pop3_capabilities "TOP" "USER";
#       # imap_capabilities "IMAP4rev1" "UIDPLUS";
#
#       server {
    
    
#               listen     localhost:110;
#               protocol   pop3;
#               proxy      on;
#       }
#
#       server {
    
    
#               listen     localhost:143;
#               protocol   imap;
#               proxy      on;
#       }
#}

这个文件是默认的配置文件，我们可以先不管，先注意几点就行：

访问日志在 /var/log/nginx/access.log
错误日志在 /var/log/nginx/error.log
主配置文件包含了 /etc/nginx/conf.d/*.conf 这个目录下所有配置

所以我们在 /etc/nginx/conf.d/ 目录下新建一个 project.conf 文件，编写如下内容：

upstream login_entrance {
    
    
    server localhost:4101;
    server localhost:4102;
}

upstream exit_entrance {
    
    
    server localhost:6101;
    server localhost:6102;
}

server {
    
    
    listen       4100;
    server_name  localhost;

    location / {
    
    

        proxy_pass http://login_entrance;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }
}

server {
    
    
    listen       6100;
    server_name  localhost;

    location / {
    
    

        proxy_pass http://exit_entrance;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }
}

server {
    
    
    listen      8100;
    server_name localhost;

    location / {
    
    
        root    /usr/share/nginx/html;
    }
}

配置文件的含义：

访问 8100 端口可以看到 nginx 欢迎页
将发送给4100端口的数据转发给4101和4102端口
将发送给6100端口的数据转发给6101和6102端口

重启nginx服务

重启可采用关闭服务器再开启的方式，也可以直接使用以下命令：

systemctl restart nginx
nginx -s reload

查看报错

当nginx启动不起来是可以通过 systemctl status nginx 命令查看，也可以直接查看 errorlog 文件，比如可能会看到如下内容：

2023/03/14 20:51:06 [emerg] 937503#937503: bind() to 0.0.0.0:4100 failed (98: Address already in use)
2023/03/14 20:51:06 [emerg] 937503#937503: bind() to 0.0.0.0:4100 failed (98: Address already in use)
2023/03/14 20:51:06 [emerg] 937503#937503: bind() to 0.0.0.0:4100 failed (98: Address already in use)
2023/03/14 20:51:06 [emerg] 937503#937503: bind() to 0.0.0.0:4100 failed (98: Address already in use)

一看就应该知道是端口4100被占用了。

负载均衡配置

负载均衡是nginx一个常见的应用，只需要在配置文件中加入一些参数即可：

轮询

这是默认的策略，把每个请求按次序逐一分配到不同可用的server，如果分配到的server不可用，则自动分配到下一个

upstream good.cc {
    
    
    server localhost:4101;
    server localhost:4102;
}

权重

weight默认值为1，值越大则代表被访问的几率越大，下面配置中4102端口的访问几率是4101的二倍

upstream good.cc {
    
    
    server localhost:4101 weight=1;
    server localhost:4102 weight=2;
}

最少连接

顾名思义就是把请求分配到连接数最少的server

upstream good.cc {
    
    
    least_conn;
    server localhost:4101;
    server localhost:4102;
}

IP哈希

根据访问客户端ip的hash值分配，这样同一客户端的请求都会被分配到同一个server上，适合有状态的服务

upstream good.cc {
    
    
    ip_hash;
    server localhost:4101;
    server localhost:4102;
}

总结

nginx 在 Ununtu 20.04 上安装非常简单，使用 apt install nginx 就行啦
nginx 的默认主配置文件是 /etc/nginx/nginx.conf 会包含同级目录下 conf.d/*.conf 所有配置
nginx 服务可以用 systemctl status nginx 方式查看
nginx 的重启方式 systemctl restart nginx 或 nginx -s reload
nginx 作为负载均衡服务器有轮询、权重、最少连接、ipHash等多种配置方式
我也是刚刚入门，关于使用方法和配置文件还有很多东西要学，后面慢慢总结吧

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记录一下第一次安装和配置Nginx