Canonical released Ubuntu 20.10, the first Ubuntu release to feature desktop images for the Raspberry Pi including a full desktop experience on it.
In the words of Mark Shuttleworth, CEO of Canonical
In this release, we celebrate the Raspberry Pi Foundation’s commitment to put open computing in the hands of people all over the world. We are honoured to support that initiative by optimising Ubuntu on the Raspberry Pi, whether for personal use, educational purposes or as a foundation for their next business venture.
Ubuntu Desktop 20.10 is optimized for Raspberry Pi images and is the first release of Ubuntu for the desktop. Support for the Ubuntu server on the Raspberry Pi, however, has been available since the 20.04 LTS release. In addition to Raspberry Pi desktop support, Ubuntu 20.10 includes GNOME 3.38 and other features as outlined in the release notes.
Ubuntu 20.10 includes Canonical's micro cloud stack combines Metal-as-a-Service (MAAS), LXD, MicroK8s, and Ceph storage. MicroK8s 1.19 and LXD 4.6 are for resilient micro clouds, small clusters of servers providing VMs and Kubernetes on the edge. MicroK8s provides the ability to orchestrate workloads on the edge. LXD allows to build a home lab appliance with its clustering and VM capabilities that become available on the Raspberry Pi via Ubuntu desktop. It's possible to do pretty much everything an average desktop user would expect on a Raspberry Pi 4.
With a Raspberry Pi 4, a microSD card (8GB recommended) and a few other accessories, it's possible to install Ubuntu Desktop as outlined in the tutorial.
A collaborative effort between the Ubuntu Desktop team, the foundations team, and the Kernel team, Ubuntu 20.10 can be downloaded from the downloads site. The video stream goes into more details on the Raspberry Pi support on Ubuntu 20.10. Usage of MicroK8s on the Raspberry is detailed in the tutorial.