The Apache module unique_id is not shown as enabled in Plesk

Symptoms

• Plesk Migrator shows the following pre-migation warning:

  PLESK_INFO: The following Apache modules are not installed on the destination server: unique_id.
  Please install and enable these modules to prevent possible problems.

• ModSecurity is installed on the destination server: Tools & Settings > Web Application Firewall (ModSecurity).

• The unique_id module is not listed at Tools & Settings > Apache Web Server and in the output of the command which shows Apache modules:

  # plesk bin optimization_settings -s | grep unique_id
  #

• When listing all enabled Apache modules using the httpd (on CentOS/RHEL) or apache2ctl (on Debian/Ubuntu) utility, unique_id is listed as enabled:

  # httpd -M | grep unique_id
  unique_id_module (shared)

  ---

  # apache2ctl -M | grep unique_id
  unique_id_module (shared)

Cause

The Apache module unique_id is always enabled by default in Plesk as it is required by ModSecurity to function properly. To eliminate the possibility to disable this module, it was hidden in Plesk.
Since it becomes impossible to check the module status using Plesk utilities, this behavior is considered as a bug with ID PPPM-11037, which is planned to be fixed in product future updates.

Resolution

No actions are required - the Apache unique_id module is enabled.

The warning message in Plesk Migrator can be safely ignored.