bind() to 0.0.0.0:80 failed (98: Address already in use) 即使只有 NGINX 运行

注意：事实证明根本没有任何问题。详情见评论。

我刚刚从 Oracle Cloud 获得了新的实例，Ubuntu 20.04 Minimized。因为我试图在这个实例上运行 DokuWiki，所以我安装了这些包：

sudo apt install net-tools lsof wget nano
sudo apt install php7.4-fpm php7.4-xml php7.4-mbstring imagemagick nginx certbot python3-certbot-nginx

我从未接触过但删除nginx.conf了符号链接并将我自己的 conf 文件与名称一起放入（虽然真实名称已被编辑）/etc/nginxdefault/etc/sites-enabled/etc/nginx/conf.dexample.com.conf

server {
    listen 80 default_server;
    server_name example.com;
    root /var/www/dokuwiki;
    index index.php index.html;

    location / { 
        try_files $uri $uri/ @dokuwiki;
    }

    location @dokuwiki {
        rewrite ^/_media/(.*) /lib/exe/fetch.php?media=$1 last;
        rewrite ^/_detail/(.*) /lib/exe/detail.php?media=$1 last;
        rewrite ^/_export/([^/]+)/(.*) /doku.php?do=export_$1&id=$2 last;
        rewrite ^/(.*) /doku.php?id=$1&$args last;
    }

    location ~ \.php$ {
        include snippets/fastcgi-php.conf;
        fastcgi_pass unix:/var/run/php/php7.4-fpm.sock;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        include fastcgi_params;
    }
    
    location ~ /(conf|bin|inc|vendor)/ {
        deny all;
    }
    
    location ~ /data/ {
        internal;
    }
}

当然，使用以下命令/var/www/dokuwiki由www-data（用户和组）拥有：

sudo chown -R www-data:www-data /var/www/dokuwiki

问题是，我无法访问我的网站。当我输入nginx终端时，它会像这样尖叫：

nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] still could not bind()

但是，我检查过没有apache2类似的东西，也没有其他进程监听端口 80。

root@redacted:~# lsof -i :80
COMMAND  PID     USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
nginx   1296     root    6u  IPv4  32966      0t0  TCP *:http (LISTEN)
nginx   1297 www-data    6u  IPv4  32966      0t0  TCP *:http (LISTEN)
nginx   1298 www-data    6u  IPv4  32966      0t0  TCP *:http (LISTEN)

root@redacted:~# 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 Sat 2021-11-06 13:24:23 UTC; 16min ago
       Docs: man:nginx(8)
    Process: 1294 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=0/SUCCESS)
    Process: 1295 ExecStart=/usr/sbin/nginx -g daemon on; master_process on; (code=exited, status=0/SUCCESS)
   Main PID: 1296 (nginx)
      Tasks: 3 (limit: 1110)
     Memory: 3.1M
     CGroup: /system.slice/nginx.service
             ├─1296 nginx: master process /usr/sbin/nginx -g daemon on; master_process on;
             ├─1297 nginx: worker process
             └─1298 nginx: worker process

Nov 06 13:24:23 redacted systemd[1]: Starting A high performance web server and a reverse proxy server...
Nov 06 13:24:23 redacted systemd[1]: Started A high performance web server and a reverse proxy server.

root@redacted:~# fuser -v 80/tcp
                     USER        PID ACCESS COMMAND
80/tcp:              root       1296 F.... nginx
                     www-data   1297 F.... nginx
                     www-data   1298 F.... nginx

由于我没有碰过nginx.conf，nginx -t所以说没有错误。但检查.conf文件失败：

root@redacted:~# nginx -tc /etc/nginx/conf.d/example.com.conf
nginx: [emerg] "server" directive is not allowed here in /etc/nginx/conf.d/example.com.conf:1
nginx: configuration file /etc/nginx/conf.d/example.com.conf test failed

但我认为这与这个问题无关（虽然不确定）。

即使使用端口 80 杀死所有进程也不起作用。

我在谷歌上搜索了这个问题的解决方案，但没有找到任何可行的解决方案。

PS。我已经从iptablesOC Web 面板打开了端口。所以端口的事情不会是我认为这个问题的原因。