Try pre-built images

Ubuntu Core runs on a variety of hardware, and pre-built images are available for amd64 and ARM platforms (among others). These images can also be installed on a virtual machine.

Pre-built images are ideal for exploration and experimentation, but they are not intended for deployment or use at scale. They include snaps to provide an onboarding 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 creating, deploying, and managing secure custom images running on your hardware.

To learn how to create your own custom image, see our Build an image guide.

Install Ubuntu Core on a VM
Try Ubuntu Core without any specific hardware from within a virtual machine
Try a pre-built image
Install a pre-built Ubuntu Core image in a supported testing platform
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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.

Most of this is already covered in the earlier Quick Start page.

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.

This is high on the priority list. There’s more on our tutorial strategy on the Ubuntu blog: https://ubuntu.com/blog/the-idea-of-a-tutorial

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?

Hello!

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.

We’ve now created a how-to on using SSH keys to access an Ubuntu Core device: Connect to Ubuntu Core with SSH

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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)

I was just about to leave the same comment – why UC22 links to “pending” directory.

(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.

Edit: Also edited to be HTTPS.

2 Likes

UC18 is already technically EOL.

Again, references to “Intel NUC” should be updated. And do we even want to keep documenting anything related to UC18 at this point?

You’re right. I’ve cut the reference to 18 and removed the Intel from NUC.

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.)

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On the published version here, the hyperlink for “Install on a Raspberry Pi” is https://ubuntu.com/core/docs/install which is the URL of the same page. It should be https://ubuntu.com/core/docs/install-on-a-raspberry-pi.

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.