Ubuntu 18.04 Bionic Beaver as Virtualbox Guest

Virtualbox guest utilities are available in the 'Multiverse' repo.
Testing on server gives the following in /etc/apt/sources.list after initial install:

• deb http://archive.ubuntu.com/ubuntu bionic main
• deb http://archive.ubuntu.com/ubuntu bionic-security main
• deb http://archive.ubuntu.com/ubuntu bionic-updates main

You may be using a different ftp/http location, but just adding 'multiverse' to each line should achieve the same result. I ended up with:

• deb http://archive.ubuntu.com/ubuntu bionic main multiverse
• deb http://archive.ubuntu.com/ubuntu bionic-security main multiverse
• deb http://archive.ubuntu.com/ubuntu bionic-updates main multiverse

I then ran the following commands to update and install the required modules:

• sudo apt update
• sudo apt install virtualbox-guest-utils virtualbox-guest-dkms dkms linux-headers-generic build essential