Use `lxd-imagebuilder` to create images¶

This guide shows you how to create an image for LXD or LXC.

Before you start, you must install lxd-imagebuilder. See How to install lxd-imagebuilder and simplestream-maintainer for instructions.

Create an image¶

To create an image, first create a directory where you will be placing the images, and enter that directory.

mkdir -p $HOME/Images/ubuntu/
cd $HOME/Images/ubuntu/

Then, copy one of the example YAML configuration files for images into this directory.

Note

The YAML configuration file contains an image template that gives instructions to LXD imagebuilder.

LXD imagebuilder provides examples of YAML files for various distributions in the examples directory. scheme.yaml is a standard template that includes all available options.

Official LXD templates for various distributions are available in the lxd-ci repository.

In this example, we are creating an Ubuntu image.

cp $HOME/go/src/github.com/canonical/lxd-imagebuilder/doc/examples/ubuntu.yaml ubuntu.yaml

Edit the template file¶

Optionally, you can do some edits to the YAML configuration file. You can define the following keys:

Section	Description	Documentation
`image`	Defines distribution, architecture, release etc.	Image
`source`	Defines main package source, keys etc.	Source
`targets`	Defines configuration for specific targets (e.g. LXD, instances etc.)	Targets
`files`	Defines generators to modify files	Generators
`packages`	Defines packages for install or removal; adds repositories	Package management
`actions`	Defines scripts to be run after specific steps during image building	Actions
`mappings`	Maps different terms for architectures for specific distributions (e.g. `x86_64: amd64`)	Mappings

Tip

When building a VM image, you should either build an image with cloud-init support (provides automatic size growth) or set a higher size in the template, because the standard size is relatively small (10 GiB). Alternatively, you can also grow it manually.

Build and launch the image¶

The steps for building and launching the image depend on whether you want to use it with LXD or with LXC.

Create an image for LXD¶

To build an image for LXD, run lxd-imagebuilder. We are using the build-lxd option to create an image for LXD.

To create a container image:

sudo $HOME/go/bin/lxd-imagebuilder build-lxd ubuntu.yaml

To create a VM image:

sudo $HOME/go/bin/lxd-imagebuilder build-lxd ubuntu.yaml --vm

See LXD image for more information about the build-lxd command.

If the command is successful, you will get an output similar to the following (for a container image). The lxd.tar.xz file is the description of the container image. The rootfs.squasfs file is the root file system (rootfs) of the container image. The set of these two files is the container image.

$ ls -l
total 100960
-rw-r--r-- 1 root   root         676 Oct  3 16:15 lxd.tar.xz
-rw-r--r-- 1 root   root   103370752 Oct  3 16:15 rootfs.squashfs
-rw-r--r-- 1 ubuntu ubuntu      7449 Oct  3 16:03 ubuntu.yaml
$

Add the image to LXD¶

To add the image to an LXD installation, use the lxc image import command as follows.

$ lxc image import lxd.tar.xz rootfs.squashfs --alias mycontainerimage
Image imported with fingerprint: 009349195858651a0f883de804e64eb82e0ac8c0bc51880

See How to copy and import images for detailed information.

Let’s look at the image in LXD. The ubuntu.yaml had a setting to create an Ubuntu 20.04 (focal) image. The size is 98.58MB.

$ lxc image list mycontainerimage
+------------------+--------------+--------+--------------+--------+---------+-----------------------------+
|      ALIAS       | FINGERPRINT  | PUBLIC | DESCRIPTION  |  ARCH  |  SIZE   |         UPLOAD DATE         |
+------------------+--------------+--------+--------------+--------+---------+-----------------------------+
| mycontainerimage | 009349195858 | no     | Ubuntu focal | x86_64 | 98.58MB | Oct 3, 2020 at 5:10pm (UTC) |
+------------------+--------------+--------+--------------+--------+---------+-----------------------------+

Launch an LXD container from the container image¶

To launch a container from the freshly created image, use lxc launch as follows. Note that you do not specify a repository for the image (like ubuntu: or images:) because the image is located locally.

$ lxc launch mycontainerimage c1
Creating c1
Starting c1

Create an image for LXC¶

Using LXC containers instead of LXD may require the installation of lxc-utils. Having both LXC and LXD installed on the same system will probably cause confusion. Use of raw LXC is generally discouraged due to the lack of automatic AppArmor protection.

To create an image for LXC, use the following command:

$ sudo $HOME/go/bin/lxd-imagebuilder build-lxc ubuntu.yaml
$ ls -l
total 87340
-rw-r--r-- 1 root root      740 Jan 19 03:15 meta.tar.xz
-rw-r--r-- 1 root root 89421136 Jan 19 03:15 rootfs.tar.xz
-rw-r--r-- 1 root root     4798 Jan 19 02:42 ubuntu.yaml

See LXC image for more information about the build-lxc command.

Add the container image to LXC¶

To add the container image to a LXC installation, use the lxc-create command as follows.

lxc-create -n myContainerImage -t local -- --metadata meta.tar.xz --fstree rootfs.tar.xz

Launch a LXC container from the container image¶

Then start the container with

lxc-start -n myContainerImage

Repack Windows ISO¶

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With LXD it’s possible to run Windows VMs. All you need is a Windows ISO and a bunch of drivers. To make the installation a bit easier, lxd-imagebuilder added the repack-windows command. It takes a Windows ISO, and repacks it together with the necessary drivers.

The lxd-imagebuilder will automatically detect the Windows version, however, it is possible to set the version manually using --windows-version flag, which allows the following values:

Flag value	Version
`w11`	Windows 11
`w10`	Windows 10
`w8`	Windows 8
`w8.1`	Windows 8.1
`w7`	Windows 7
`xp`	Windows XP
`2k22`	Windows Server 2022
`2k19`	Windows Server 2019
`2k16`	Windows Server 2016
`2k12`	Windows Server 2012
`2k12r2`	Windows Server 2012 R2
`2k8`	Windows Server 2008
`2k8r2`	Windows Server 2008 R2
`2k3`	Windows Server 2003

When repacking a Windows ISO, lxd-imagebuilder uses external tools that may need to be installed. On a Ubuntu/Debian system, those can be installed with:

sudo apt-get install -y --no-install-recommends genisoimage libwin-hivex-perl rsync wimtools

Here’s how to repack a Windows ISO:

sudo lxd-imagebuilder repack-windows path/to/Windows.iso path/to/Windows-repacked.iso

More information on repack-windows can be found by running

lxd-imagebuilder repack-windows -h

Install Windows¶

Run the following commands to initialize the VM, add a TPM device, increase the allocated disk space, CPU, memory and finally attach the full path of your prepared ISO file.

lxc init win11 --empty --vm
lxc config device add win11 vtpm tpm path=/dev/tpm0
lxc config device override win11 root size=50GiB
lxc config set win11 limits.cpu=4 limits.memory=8GiB
lxc config device add win11 iso disk source=/path/to/Windows-repacked.iso boot.priority=10

Now, the VM win11 has been configured and it is ready to be started. The following command starts the virtual machine and opens up a VGA console so that we go through the graphical installation of Windows.

lxc start win11 --console=vga

Once done with the manual installation process, the ISO can be removed to speed up next boots by avoiding the prompt to boot from it.

lxc config device remove win11 iso