The PHP-FPM user should be a special user that you create for running your website, whether it is Magento, WordPress, or anything. Its characteristics are the following:
- This is the user that PHP-FPM will execute scripts with
- This user must be unique. Do not reuse an existing user account. Create a separate user for each website!
- Do not reuse any sudo capable users. If your website user is ubuntu or centos, or, root – you’re asking for much trouble.