PHP-FPM (FastCGI Process Manager) is an alternative to FastCGI implementation of PHP with some additional features useful for sites with high traffic. It is the preferred method of processing PHP pages with NGINX and is faster than traditional CGI based methods such as SUPHP or mod_php
for running a PHP script. The main advantage of using PHP-FPM is that it uses a considerable amount of less memory and CPU as compared with any other methods of running PHP. The primary reason is that it demonizes PHP, thereby transforming it to a background process while providing a CLI script for managing PHP request.
Here’s a simplified overview of how PHP-FPM works:
Nginx doesn’t know how to run a PHP script of its own. It needs a PHP module like PHP-FPM to efficiently manage PHP scripts. PHP-FPM, on the other hand, runs outside the NGINX environment by creating its own process. Therefore when a user requests a PHP page the nginx server will pass the request to PHP-FPM service using FastCGI. The installation of php-fpm in Ubuntu depends on PHP and its version. Check the documentation of installed PHP before proceeding with installing FPM in your server. Assuming you have already installed the latest PHP 7.3, then you can install FPM using the following apt-get
command.
The FPM service will start automatically, once the installation is over. You can verify that using the following systemd command:
The php-fpm service creates a default pool, the configuration (<www.conf>) for which can be found in /etc/php/7.3/fpm/pool.d
folder. You can customize the default pool as per your requirements. But it is a standard practice to create separate pools to have better control over resource allocation to each FPM processes. Furthermore, segregating FPM pool will enable them to run independently by creating its own master process. That means each php application can be configured with its own cache settings using PHP-FPM. A change in one pool’s configuration does not require you to start or stop the rest of the FPM pools. Let us create an FPM pool for running a PHP application effectively through a separate user. To start with, create a new user who will have exclusive rights over this pool:
Now navigate to the FPM configuration directory and create a configuration file using your favorite text editor like vi:
The above FPM configuration options and their values are described below.
env['PHP_FOO'] = $bar
. For example, adding the following options in the above configuration file will set the hostname and temporary folder location to the PHP environment.Also, the process managers settings in the above pool configuration file are set to dynamic. Choose a setting that best suits your requirement. The other configuration options for process manager are:
Once you are done with creating the above configuration file, restart fpm service to apply new settings:
The FPM pool will be created immediately to serve php pages. Remember, you can create a separate systemd service by specifying the above FPM configuration file thereby enabling you to start/stop this pool without affecting other pools.
Now create an NGINX server block that will make use of the above FPM pool. To do that, edit your NGINX configuration file and pass the path of pool’s socket file using the option fastcgi_pass
inside location block for php.
Make sure the above configuration setting is syntactically correct and restart NGINX.
To test if the above NGINX configuration file is indeed using the newly created FPM pool, create a php info file inside the web root. I have used /var/www/html/wordpress
as a web root in the above NGINX configuration file. Adjust this value according to your environment.
Once you are done with creating the PHP info page, point your favorite web browser to it. You will notice that the value of $_SERVER['USER']
and $_SERVER['HOME']
variable are pointing to wordpress_user
and /home/wordpress_user
respectively that we set in the FPM configuration file previously and thus confirms that the NGINX is serving the php pages using our desired FPM pool.
PHP-FPM (FastCGI Process Manager) is a process manager for PHP that improves performance and security by efficiently managing PHP processes. Using PHP-FPM with NGINX enhances performance, security, and resource management, making it ideal for high-traffic and demanding PHP applications.
To connect NGINX to PHP-FPM, you need to configure NGINX to use the PHP-FPM service as a FastCGI server. This is typically done by specifying the fastcgi_pass
directive in the NGINX configuration file, pointing to the PHP-FPM socket or TCP address. For example: fastcgi_pass unix:/var/run/php/php7.2-fpm.sock;
or fastcgi_pass 127.0.0.1:9000;
. This allows NGINX to forward PHP requests to the PHP-FPM service for processing.
Here’s an example of how the configuration might look in your NGINX configuration file:
Using a socket allows for faster communication between NGINX and PHP-FPM as it eliminates the need for network overhead. A port, on the other hand, requires network communication, which can be slower. However, using a port can be beneficial in scenarios where PHP-FPM is running on a different server or container.
For example, if you’re using a socket:
And if you’re using a port:
To fix a 502 Bad Gateway error from PHP-FPM, ensure that PHP-FPM is running and the socket or TCP address specified in the NGINX configuration is correct. Check the PHP-FPM logs for errors and adjust the pool settings as needed. Additionally, verify that the NGINX configuration is correctly passing PHP requests to PHP-FPM.
You can check the PHP-FPM logs by running the following command:
To run multiple PHP versions with NGINX, you can configure separate PHP-FPM pools for each version and specify the corresponding pool in the NGINX configuration for each domain or subdomain. This allows you to use different PHP versions for different applications or domains.
For example, if you have two PHP versions, PHP 7.2 and PHP 7.4, you can configure two separate pools in your PHP-FPM configuration file:
Then, in your NGINX configuration, you can specify the corresponding pool for each domain or subdomain:
The PHP-FPM pool configuration is typically located in /etc/php/7.x/fpm/pool.d/
directory, where 7.x
is the PHP version.
To optimize PHP-FPM performance, adjust the pm.max_children
, pm.start_servers
, and pm.min_spare_servers
settings in the PHP-FPM pool configuration to balance the number of processes with available system resources. Additionally, consider enabling pm.status_path
for monitoring and pm.max_requests
to recycle processes and prevent memory leaks.
Here’s an example of optimized pool configuration:
In this article, we learned how to install php-fpm and configure separate pools for different users and applications. We also learned how to configure an NGINX server block to connect to a PHP-FPM service. PHP-FPM provides reliability, security, scalability, and speed along with a lot of performance tuning options. You can now split the default PHP-FPM pool into multiple resource pools to serve different applications. This will not only enhance your server security but also enable you to allocate server resources optimally!
If you’re looking to expand your knowledge of PHP-FPM and NGINX, here are some helpful resources:
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Thank you for your tutorial. I am plan to install Nginx server separately with PHP server. Meaning Nginx in one server and PHP is in another server…And the NGINX server will located at DMZ zone and will face the internet. My question is: 1) Which server we need to install PHP-FPM? In Nginx server or in php server? 2) And how these two server will communicate? Which confuguration files need to alter? Sorry if my question is sound silly :). I am new to php-fpm and still in the midst of understanding it. Thank you.
- Paklah
when ever i m trying to execute php file from browser it gets download
- aditya
I have deployed a web app to AWS and php-fpm is occupied most of the CPU cores. sometimes it makes the server crash. Can there be something wrong with the configuration?
- vishal
Please add - if necessary: $ cd /project/path $ sudo chwon -R wordpress_user:wordpress_user . Because without that PHP-FPM can’t access to the files ;/
- Piotr