How does nginx find the default root directory (root html)

How does nginx find the default root directory (root html)

nginx exit configuration

server {
        listen       80;
        server_name  127.0.0.1;

        location / {    
            root   html;    # 这是一个相对路径
        }

        error_page  404              /404.html;     #当状态码为400则转到/404.html
        error_page   500 502 503 504  /50x.html;    #当状态码为50x.. 则转到/50x.html
        location = /50x.html {
            root   html;
        }
}

The nginx configuration file is on the system /etc/nginx/nginx.conf, and index.htmlthe location of the service is /var/lib/nginx/html/index.html. Now, look at the above configuration, how is nginx found according to the configuration /var/lib/nginx/html/index.html?

answer

This involves the mechanism by which nginx finds relative paths. nginx will put --prefixthe splicing in front of the relative path to form a complete path together.

--prefixThe installation may be different in different environments. nginx -VYou can view the relevant configuration by

nginx -V
nginx version: nginx/1.24.0
built with OpenSSL 3.1.0 14 Mar 2023
TLS SNI support enabled
configure arguments: --prefix=/var/lib/nginx --sbin-path=/usr/sbin/nginx --modules-path=/usr/lib/nginx/modules --conf-path=/etc/nginx/nginx.conf --pid-path=/run/nginx/nginx.pid --lock-path=/run/nginx/nginx.lock --http-client-body-temp-path=/var/lib/nginx/tmp/client_body 
......
......

You can see the above --prefix=/var/lib/nginx, so the full path of the html that nginx looks for at this time is/var/lib/nginx/html