Install Ubuntu Core on a VM

[degville]

NOTE TO EDITORS

This page of documentation has moved to:
https://documentation.ubuntu.com/core/tutorials/try-pre-built-images/install-on-a-vm

It will continue to be updated and supported only from the new location. We also welcome community contributions.

To suggest improvements, or to notify us of an issue, please use the Give feedback button on the new page. Thank you!

You can try Ubuntu Core without any specific hardware from within a virtual machine using Multipass on Windows, Mac and Linux. Multipass has integrated support for the latest Ubuntu Core images and can launch and run virtual machines from a single command.

If you need to test your own Ubuntu Core images, see Test Ubuntu Core with QEMU. QEMU, is more configurable than Multipass and can boot either a supported image or a custom image, with or without TPM emulation and full disk encryption.

Boot Ubuntu Core with Multipass

If you don’t yet have Multipass installed, see Install Multipass. If it’s installed, the following command will output its current state:

multipass info

List available images

To list which images Multipass currently has available, type multipass find.

The output will include Ubuntu Core images alongside standard Ubuntu images:

Image       Aliases           Version          Description
core20                        20230119         Ubuntu Core 20
core22                        20230717         Ubuntu Core 22
20.04        ocal             20240129.1       Ubuntu 20.04 LTS
22.04        ammy,lts         20240126         Ubuntu 22.04 LTS
daily:24.04  noble,devel      20240129         Ubuntu 24.04 LTS

Ubuntu Core 24: Multipass images for Ubuntu Core 24 are currently being tested. They are available from the edge version of the Multipass snap (snap refresh multipass --edge) and they’ll become available from all stable releases shortly.

Launch an image

To create a new instance and boot your choice of Ubuntu Core image, type:

multipass launch <image-name> -n <instance-name>

For example, the following command will launch and boot core22 with an instance name of mycore22:

multipass launch core22 -n mycore22

The image is downloaded and locally cached when it’s launched for the first time.

Access a running instance

You can connect to a running instance of Ubuntu Core by opening a shell environment on that running instance:

multipass shell mycore22

You are now operating within the Ubuntu Core environment. See First steps with Ubuntu Core for suggestions on what to try.

[gzanchi]

I see that the “Install Multipass” links point to the “Install” page on the website, not sure if in the context of this guide it would make more sense to link the actual documentation page: How to install Multipass, or if it’s best to keep it light and high-level as in the currently linked page.

[degville]

Thank you for the suggestion! I think you’re right - the page you suggest is a better cross-platform fit.

[r.smith]

The new version of multipass (1.14.0) supports deploying Core22 and Core24. Although, GUI support on Hypver-V has been lacking. Good News! The updated kernels used by Core24 contain a new display driver hyperv_drm that works with ubuntu-frame. To use this new display driver, you must blacklist hyperv_fb.

# /etc/modprobe.d/blacklist-hyperv-fb.conf
# Force the use of hyperv_drm for ubuntu-core wayland support
blacklist hyperv_fb

I use a custom cloud-config to apply the change through the multipass --cloud-init option.

#cloud-config
write_files:
## Blacklist hyperv_fb to force hyperv-drm
- path: /etc/modprobe.d/blacklist-hyperv-fb.conf
permissions: ‘0644’
content: |
# Force the use of hyperv_drm for ubuntu-core wayland support
blacklist hyperv_fb

[degville]

Thanks so much for letting us know. I’ll update the doc to incorporate this, and to show ubuntu-frame running. Thanks!

[bryanfraschetti]

Hello,

I think it could be beneficial to add some documentation about installing a custom Ubuntu Core in LXD - similar to the multipass instructions that are here.

It’s a bit of overhead but not too much of a hassle and would be useful for those more familiar with the LXD interface. For example, after building a core image with ubuntu-image with:

ubuntu-image snap -O img my-model.model

It can be converted for LXD usage in a couple commands.

First extract and convert the image to qcow2 format

qemu-img convert img/pc.img -p -f raw -O qcow2 core.qcow2

Then write the image metadata to a yaml and create a compressed tar

cat > metadata.yaml <<EOF
architecture: x86_64
creation_date: $(date +%s)
properties:
  description: core
  os: Ubuntu Core
  release: <Ubuntu-image-codename> <Ubuntu-version-number>
EOF

tar cJf metadata.tar.xz metadata.yaml

Finally, import it into LXD

lxc image import metadata.tar.xz core.qcow2 [--alias <alias-name>]

From there onward it can be interacted with as any other lxc image:

lxc launch --vm <alias-name> [<vm-name>]

which powers on the UC VM that can subsequently be accessed by ssh, as normal for UC

Let me know your thoughts! Thanks

[degville]

This is fantastic, thank you so much! I’m going to use this as the basis for a separate section on building images for LXD.