The error message "unit php8.1-fpm.service could not be found" indicates that the systemd unit file for the PHP-FPM service version 8.1 is not present on your system. This error typically occurs when the specified service unit file is missing or the service itself is not installed.
Here are steps to troubleshoot and resolve the issue:
Check PHP-FPM Installation:
Ensure that PHP-FPM version 8.1 is installed on your system. You can do this by running the following command:
sudo apt list --installed | grep php8.1-fpm
If the service is not installed, you'll need to install it using your package manager. If PHP-FPM 8.1 is not available in your package repositories, you might need to use a different PHP version or follow specific installation instructions for PHP 8.1.
Check Unit File:
Verify that the PHP-FPM service unit file exists for version 8.1. Unit files are typically located in /lib/systemd/system/ or /etc/systemd/system/. You can check if the unit file exists by listing the files in these directories:
ls /lib/systemd/system/ | grep php8.1-fpm ls /etc/systemd/system/ | grep php8.1-fpm
If you don't find the unit file, it might mean that the service was not installed properly or that you're using a different version of PHP-FPM.
Check Correct Service Name:
Verify that you're using the correct service name for PHP-FPM version 8.1. The service name might differ based on the specific PHP version and your distribution. The correct service name should match the version you have installed.
Check PHP Version:
Ensure that PHP version 8.1 is installed on your system. You can check the installed PHP versions using:
If PHP 8.1 is not installed, you won't have the corresponding PHP-FPM service for that version.
Check Systemd Unit Status:
If the service is installed, but you're still encountering the issue, check the status of systemd units:
systemctl list-units --type=service | grep php
This will list all active service units with "php" in their names. Look for any related to PHP-FPM and verify the correct service names.
If you're still having trouble after these steps, consider seeking assistance from your system administrator or checking online resources specific to your Linux distribution and PHP version.