HTTP return code

5XX Series

500

Internal service errors Internal Server error

The reasons are: large traffic, server resources, or internal execution errors, such as back-end MySQL hangs.

502 (same as 504 case)

Bad Gateway

The reasons are generally:

1 Nginx appears 502 There are many reasons, but most of the reasons can be attributed to insufficient resources, that is, the backend php-fpm processing problems, Nginx sent the correct client request to the back-end of the PHP-FPM process, But because of the problem of the PHP-FPM process, the PHP code could not be parsed correctly, and eventually returned to the client 502 error

2 php-fpm hung up.

503

Service temporarily unavailable

The reasons are generally:

1 Access concurrency too many

2 Nginx does the concurrency limit, the same IP access operation limit

Limit_conn one 1;

504

Gateway Time-out Gateways Timeout

Reason:

1 The number of Nginx worker is sufficient

Ps-ef |grep php-fpm |wc-l minus 2

2

Fastcig buffering (buffer) or proxy cache situation, if the cache is too small, set a short time, the machine is busy, the opportunity to appear 502

3 PHP takes a long time to execute, while setting the timeout time is short. Related Instructions

Fastcgi_connect_timeout 60;

Fastcgi_send_timeout 60;

Fastcgi_read_timeout 60;

5,021 as related to php-fpm.conf, 541-like and nginx nginx.conf configuration, it is possible to be related to Nginx and back end.

This article is from the "Tridewah operation and maintenance work Road" blog, please be sure to keep this source http://cuidehua.blog.51cto.com/5449828/1829225

HTTP return code