How to solve the 502 error in php

The solution to the 502 error in php is: 1. Increase the number of fastcgi processes; 2. Increase the number of files opened by the Linux kernel; 3. Edit the configuration file nginx.conf and adjust the script execution time; 4. Add cache configuration to the nginx.conf configuration file.

Analysis:

This will occur if the number of php-cgi processes is not enough, the php execution time is long, or the php-cgi process dies. 502 error.

How to solve?

1. Increase the number of processes

Use netstat -napo | grep "php-fpm" | wc -l to check the current fastcgi process The number, if the number is close to the upper limit configured in conf, you need to increase the number of processes.

But you can’t increase it endlessly. You can adjust the number of php-fpm sub-processes to 100 or more according to the server memory. On a server with 4G memory, 200 is enough.

2. Increase the number of files opened by the linux kernel

You can use these commands (must be the root account)

echo 'ulimit -HSn 65536'>> /etc/profile
echo 'ulimit -HSn 65536'>> /etc/rc.local
source /etc/profile

3. Adjust Script execution time

If the script waits for a long time without returning for some reason, resulting in new requests not being processed, you can appropriately adjust the following configuration.

nginx.conf The main contents are as follows:

fastcgi_connect_timeout 300;
fastcgi_send_timeout 300;
fastcgi_read_timeout 300;

php-fpm.conf If the contents are as follows

request_terminate_timeout =10s

4. Add cache

Modify or add configuration to nginx.conf

proxy_buffer_size 64k;
proxy_buffers  512k;
proxy_busy_buffers_size 128k;

If you need to learn more knowledge, please visit php Chinese website.

The above is the detailed content of How to solve the 502 error in php. For more information, please follow other related articles on the PHP Chinese website!