504 Gateway Time-out - upstream timeout

Question

Everything was running smoothly when suddenly my server stopped working. I'm using Linode with Nginx fast-cgi

This is my log file:

upstream timed out (110: Connection timed out) while reading response header from upstream, client: 76.66.174.147, server: iskacanada.com, request: "GET / HTTP/1.1", upstream: "fastcgi://127.0.0.1:9000", host: "www.iskacanada.com"

location ~ \.php$ {
    include        fastcgi_params;
    fastcgi_read_timeout 120;
    fastcgi_pass   localhost:9000;
    fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;
}

When I want to restart mysql it says:

sudo service mysql restart stop: Unknown instance: start: Job failed to start

Any idea of what is going on?

Solution 1

After a few hours of Debugging here is how I did it:

Using Ubuntu 12.04, Nginx and php5-fmp

1. PLease check your log files! log files are your friends. a 504 Gateway problem means that my server is not communicating properly with the website. So In my case I had Nginx and php-fpm that was managing the requests. I had to check 2 log files:

   /var/log/nginx/error.log and /var/log/php5-fpm.log

in error.log:

recv() failed (104: Connection reset by peer) while reading response header from upstream, client: 76.66.174.147, server: xxxxxxx.com, request: "GET /wp-admin/ HTTP/1.1", upstream: "fastcgi://127.0.0.1:9000", host: "www.xxxxxxx.com"

in php5-fpm.log:

unable to bind listening socket for address '127.0.0.1:9000': Address already in use (98)

So I figured out that I needed to check my php5-fpm process by typing

netstat | grep 9000
tcp        0      0 localhost.localdom:9000 localhost.localdo:58424 SYN_RECV   
tcp      913      0 localhost.localdom:9000 localhost.localdo:57917 CLOSE_WAIT 
tcp      857      0 localhost.localdom:9000 localhost.localdo:58032 CLOSE_WAIT 
tcp     1633      0 localhost.localdom:9000 localhost.localdo:58395 CLOSE_WAIT 
tcp      961      0 localhost.localdom:9000 localhost.localdo:58025 CLOSE_WAIT 
tcp      857      0 localhost.localdom:9000 localhost.localdo:58040 CLOSE_WAIT 
tcp      953      0 localhost.localdom:9000 localhost.localdo:58005 CLOSE_WAIT 
tcp      761      0 localhost.localdom:9000 localhost.localdo:58016 CLOSE_WAIT 
tcp     1137      0 localhost.localdom:9000 localhost.localdo:57960 CLOSE_WAIT

Lots of close_wait!!! that's abnormal...so I killed all the processes by typing
fuser -k 9000/tcp

I then changed my

/etc/php5/fpm/pool.d/www.conf

and changing this:

request_terminate_timeout=30s

Now the website works. I hope this solved the problem since it was intermittent.

Solution 2

Check if PHP is still running: sudo ps aux | grep php

If it is, restart it sudo service php5-fpm restart if not start it sudo service php5-fpm start.

If you need to restart your database only pass restart, stop or start to the service command: sudo service mysql start or sudo service mysql restart or sudo service mysql stop.