Summary of common server error codes

One ：500 error

1、500 Internal Server Error Internal service error ： seeing the name of a thing one thinks of its function 500 An error is usually an unexpected situation on the server , And can't complete the request .

2、500 The possibility of error ：

a、 Programming language syntax error ,web Script error

b、 Concurrent high time , Because of system resource constraints , You can't open too many files

3、 General solutions ：

a、 see nginx、php Error log file for , So we can see the clue

b、 If it is too many open files, modify nginx Of worker_rlimit_nofile Parameters , Use ulimit Check the system open file limit , modify /etc/security/limits.conf, Still there too many open files, Then consider load balancing , Spread the traffic to different servers

c、 If it's a script problem , You need to fix script errors , Optimize the code

Two ：502、504 error

1、502 Bad Gateway error 、504 Bad Gateway timeout gateway timeout

2、502、504 The possibility of occurrence

web Server failure 、 The program process is not enough

3、 General solutions

	a、 Use nginx agent , And the back-end server fails ; perhaps php-cgi Not enough processes ;
	php Long execution time , Or is it php-cgi The process is dead ; already fastCGI Usage and so on can lead to 502、504 error .

	b、502  It means requested php-fpm Has been performed , But for some reason it didn't finish , Eventually lead to php-fpm Process termination .
	 Generally speaking , And php-fpm.conf The settings of , Also with the php Is related to the performance of the program , There's a lot of traffic on the site , and php-cgi Less processes .
	 In view of this situation 502 error , Just add  php-cgi The number of processes .
	 Specifically, it is to modify /usr/local/php/etc/php-fpm.conf file , Will be one of the max_children A proper increase in value .
	 This data should be set according to the configuration of your server .
	 Generally one php-cgi Process accounting 20M Memory , You can calculate it yourself , Moderate increase .

         /usr/local/php/sbin/php-fpm reload  Then restart .

	c、504  Said the timeout , That is, the request from the client did not arrive at the gateway , The request is not available for execution php-fpm.
	 And nginx.conf It also has something to do with the configuration of .

501　　 The server does not have the function to complete the request . for example , This code may be returned when the server does not recognize the request method .

503　　 The server is currently unavailable （ Maintenance due to overload or shutdown ）. Usually , It's just a temporary situation .（ Service not available ）

505　　 The server does not support the HTTP Protocol version .（HTTP Version not supported ）

Other related articles ：

Web Server error code ：https://blog.csdn.net/weixin_33778544/article/details/94172117