High CPU load. A lot of processes interface_async_executor.php (servershield/library/EventListener)

Symptoms

• High CPU load on a server with a great number of domains (a few hundreds) and ServerShield by Cloudflare extension.

• There are a log of the processes like below during Plesk Daily Maintenance task:

  CONFIG_TEXT: /usr/local/psa/admin/bin/event_handler -i -u psaadm /usr/local/psa/admin/bin/php -- -f /usr/local/psa/admin/plib/scripts/interface_async_executor.php -- EventListener /usr/local/psa/admin/plib/modules/servershield/library/EventListener

• /var/log/plesk/panel.log with enabled debug mode shows the following entries:

  CONFIG_TEXT: DEBUG [panel] [5d518d4c54248] Asynchronously call interface implementation /usr/local/psa/admin/plib/modules/servershield/library/EventListener.php

Cause

This is a ServerShield by Cloudflare extension bug which should be fixed by Cloudflare. For tracking purposes internal ID #EXTPLESK-1202 has been created for this issue.

Resolution

For Linux as a temporary workaround apply the following hotfix:

1. Connect to the server via SSH

2. Backup the file /usr/local/psa/admin/plib/modules/servershield/library/EventListener.php:

   # mv /usr/local/psa/admin/plib/modules/servershield/library/EventListener.php{,.orig}

3. Download the archive with the patched file, unpack it and replace the backed up file with the patched file:

   # wget https://plesk.zendesk.com/hc/article_attachments/360044365053/EventListener.tar.gz 
   # tar -zxvf ./EventListener.tar.gz
   # mv ./EventListener.php /usr/local/psa/admin/plib/modules/servershield/library/

For Windows servers replace the original file %plesk_dir%\admin\plib\modules\servershield\library\EventListener.php with the patched one from the same archive in attachments to this article.