500 Internal Server Error with nginx local host

Question

I am using Linux Mint 17. I am trying to setup PHP 7.1 or PHP 7.2 with nginx but whenever I access a php script I get 500 Internal Server Error. Whenever I restart nginx or PHP, I receive no errors.

Here are the contents of /etc/nginx/conf.d/default.conf:

server {
    listen       80;
    listen   [::]:80 default_server ipv6only=on; ## listen for ipv6
    server_name  localhost;

    #charset koi8-r;
    #access_log  /var/log/nginx/host.access.log  main;

    location / {
        root   /usr/share/nginx/html;
        index index.php 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   /usr/share/nginx/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 unix:/var/run/php7.2-fpm.sock;
        #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;
    }
}

Any help would be greatly appreciated, as I urgently need to get this working.

Edit

I fixed the 500 Error by adding worker_rlimit_nofile 100048 and changing worker_connections to 100048. Unfortunately, now it says "An error occurred" and the logs show:

2018/02/11 21:53:23 [crit] 13219#13219: *1012 open() "/usr/share/nginx/html/50x.html" failed (24: Too many open files), client: 127.0.0.1, server: localhost, request: "GET /info.php HTTP/1.0", upstream: "http://127.0.0.1:80/info.php", host: "127.0.0.1"
2018/02/11 21:53:48 [crit] 13263#13263: *56464 connect() to 127.0.0.1:80 failed (99: Cannot assign requested address) while connecting to upstream, client: 127.0.0.1, server: localhost, request: "GET /info.php HTTP/1.0", upstream: "http://127.0.0.1:80/info.php", host: "127.0.0.1"

Solution

I guess it does have nothing to do with the worker settings you mentioned.

Also having two locations location ~ \.php$ { does not make sense. I read from your comments that you've alradey removed the first one:

    location ~ \.php$ {
    proxy_pass   http://127.0.0.1;
}

Good.

Now find out why PHP-fpm is not working:

• Is PHP-fpm installed and running? Check with service php7.2-fpm status

• Where has the socket file gone? Check settings in your socket config file here /etc/php/7.2/fpm/pool.d/

• Check if PHP-fpm uses the correct user with permissions for the application folders.

Other nginx config issues:

• Add try_files:

  location / {
      try_files $uri $uri/ /index.php?$args;
  }
  

• remove the root html; line from your location ~ \.php$ {section.

• Don't put these two lines in a location section. Just add them without location / { } around:

  root   /usr/share/nginx/html;
  index index.php index.html index.htm;
  

Comments

[Jonah Benton]

nginx is listening on port 80, but is also being configured to use port 80 as an upstream (under the "proxy php scripts to apache listening on 127.0.0.1:80"). try getting rid of that location block.

[Michael Hampton]

It looks like nginx is proxying back to itself, not to Apache.

[Michael Hampton]

Then you should change or remove that section.

[Dan Bray]

@JonahB I commented that code out and it solved the error. Unfortunately, I now get a different error, *1 connect() to unix:/var/run/php7.2-fpm.sock failed (2: No such file or directory) while connecting to upstream, client: 127.0.0.1, server: localhost, request: "GET /index.php HTTP/1.1", upstream: "fastcgi://unix:/var/run/php7.2-fpm.sock:", host: "localhost". The file php7.2-fpm.sock appears to have disappeared.

[Dan Bray]

I got it working. I had to repeatedly check out the log files to fix the problem. There was a problem with fastcgi_param. The default line, '#fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name;` is completely wrong. There was also a permissions problem with the sock file that I fixed with sudo chmod 777 /run/php/php7.2-fpm.sock.

[Bob]

Good to hear you got it working! :-) Yes, that fastcgi_param line should probably be fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;. I did not mention that as it was commended out #already in your config. Your sudo chmod 777 is only a temporary solution and might break on further config changes or restarts. I suggest setting the correct permissions permanently in the according pool config file here /etc/php/7.2/fpm/pool.d/.