I recently obtained a KVM virtual server on SolusIO platform, and I want to install Ubuntu 20.04 Server from the official ISO image. This is not as easy as I hoped, but I figured it out.
Note: if you are in a hurry, skip the "Background" and start from "Part 1" section.
Background: SolusIO cannot Mount ISO Image
SolusIO is a virtual infrastructure management solution published by Plesk International Gmbh, the same company behind the popular SolusVM software. They describe SolusIO to be the successor of SolusVM, with more focus on the self-service approach for end users.
SolusIO inherits the same clean user interface from SolusVM, and is easy to use. However, as a power user, I notice several features are missing in SolusIO. One of these features is the ability to install the operating system from an ISO image.