Ubuntu Core runs on a variety of hardware, and pre-built testing images are available for amd64 and ARM platforms (among others). These images can also be installed on a virtual machine.
Testing images are ideal for exploration and experimentation, but they are not intended for deployment or for use at scale. They include snaps to provide an on-boarding and evaluation experience, alongside an SSH connection, and these are unlikely to be required in your own Ubuntu Core deployment.
Ubuntu Core has instead been designed to facilitate the creation, deployment, and management of secure custom images running on your own hardware.
To learn how to create your own custom image, see our Build an image guide.
Thank you for this post. I did notice a few problems with the instructions. The qemu command is provided, but there appears to be a duplicate line with part of the word “user” missing on line 2. Also the ubuntu core image is said to be named uc.img, but the command attempts to use an image of pc.img.
Also the text below the SSH command is copied form the previous instruction and does not make much sense.
Some of the corrections may help others in the future.
Hello - thanks so much for taking the trouble to let us know about those errors. I’ve fixed them, and sorry they made their way into the tutorial unchecked. They looked like the pasted detritus from a broken editing session.
Yes, this is true. We’re in the process of moving these docs to use the Diátaxis framework (https://diataxis.fr/) and these tutorials need to be updated and expanded. It won’t remove the duplication, but will make each rigorously conceived, implemented and tested, targetting specific platforms.
I installed core 22 on a RPi. I yes to the fingerprint and then it asks for a password. Does not accept my ONE password. same if I reboot the system an]d ssh in again, this time direct, still asks for a password. Is there a default?
To connect to your Pi, you will need to make sure 1) you have a public SSH key registered with your Ubuntu One account, and 2) the local ssh command uses the associated private key (a password isn’t used as the connection is authenticated through this key pair).
There’s a little more information on how to connect here:
The complete process, including key generation is under the “Generating an SSH key pair” heading in this tutorial:
Thanks for bringing this up. I think we should have done a better job making this clearer. I’ll update the docs to make it more explicit.
Is there a reason this doesn’t this point to Ubuntu Core 22 (stable) Daily Build ? FWIW, neither of these UC22 install targets (ubuntu-core-22-amd64.img.xz) works for me if I target a laptop (UC20 seems to at least boot)
(and @sergiusens) Thanks for flagging this. There’s no current reason why this was pending. It was copied from Support platforms which also had the same link, and I think at one time only Pending images were working. I’ve updated both now. I’ll also test the new images - although I did test x86_64 UC22 images with KVM last week.
This page mentions that one has to decompress the downloaded images with “xz”. While this is true for the dd case (or just pipe xzcat’s output into dd), for the Raspberry Pi Imager case, this is unnecessary, as the tool handles decompression automatically (and it’s faster and causes less SSD wear on your machine if one can just decompress on the fly during flashing).
This is also mentioned on the “Raspberry Pi” subpage:
The xz file can be selected without being decompressed first.
(Oh, and Installing Ubuntu Core on a NUC | Ubuntu already shows the xzcat use case, so definitely the documentation has all the parts in there, just on this page, it’s mentioning a different method.)
Thanks for letting us know. I think that problem as actually a broken redirect at the time - we had some issues with these over the last couple of days. But we’re also editing these pages quite significantly ahead of the 24.04 release, which is why they keep changing, although the new structure should be set now.