Follow below steps add SWAP space to an existing Linux Debian server:

• Create 2GB swap_file in /swap directory:
  dd if=/dev/zero of=/swap/swap_file bs=1M count=2048
  
  
• Setup file permissions:
  chmod 0600 /swap/swap_file
  
  
• Setup Linux swap area:
  mkswap /var/cache/swap/myswap
  
  
• Enable swapping:
  sudo swapon /var/cache/swap/myswap

Issue

Plesk web host server is sending following emails multiple times a day:

From: This email address is being protected from spambots. You need JavaScript enabled to view it.
Subject: Cron <root@localhost> /usr/bin/kcarectl --auto-update --gradual-rollout=auto
Content: The IP 76.15.48.179 was already used for trialing on 2018-07-05

Read more: The IP was already used for trialing on...

Issue

After upgrading PHP from 5.4.16 to 5.6.36 web pages that contain PEAR mail scripts fail to load with Error 500 (Internal Server Error)

After enabling display_errors in PHP settings following errors were displayed:

Warning: require_once(Mail.php): failed to open stream: No such file or directory in /var/www/vhosts/domain.com/httpdocs/forms/contact_form.php on line 18

Fatal error: require_once(): Failed opening required 'Mail.php' (include_path='.:/opt/plesk/php/5.6/share/pear') in /var/www/vhosts/domain.com/httpdocs/forms/contact_form.php on line 18

Read more: Warning: require_once(Mail.php): failed to open stream

This tutorial shows how I installed and setup Ubiquiti UniFi Controller on 1&1 CentOS 7 VPS web server using Docker Container.

• Login to Plesk Control Panel, open Docker, search for jacobalberty/unifi, and Run latest version.
  
• Uncheck Automatic port mapping and remap ports that are already used by other services on the server. In my case, I remapped port 8880 (to 8881) and port 8443 (to 8444).
  

  Read more: Installing Ubiquiti UniFi Controller on CentOS Docker Container (Plesk)