Aegir is a hosting system built in Drupal, for Drupal.
It lets you easily create new Drupal sites and create databases, filesystems, virtual hosts etc. for the sites. You can manage hundreds or thousands of sites using a simple Drupal based UI. As simple as you would manage a list of 100 blog posts, you can manage 100 Drupal websites.
Currently the latest released version of Aegir is: Aegir 3.
Aegir 3 relies on Drush 8, which means it can work with: Drupal 7; Drupal 8 and Drupal 9. But not Drupal 10. Oh.
I have need for it to...