Incus is a next generation system container and virtual machine manager. It offers a unified user experience around full Linux systems running inside containers or virtual machines

General informations

This repository contains my personal manifests to build custom Incus container and virtual machine images using Distrobuilder in my homelab. These manifests are based on Linux Containers project manifests they use for their image server.

Images

The following images are known to work using these manifests, other distribution versions may not work.

Distribution	Release	Variants	Container	Virtual machine
Ubuntu	noble	default	✅	✅
Ubuntu	jammy	default	✅	✅
Talos Linux	-	default	❌	✅

Requirements

• Incus >= 6.0
• Distrobuilder >= 3.0 (edge version is recommended)
• System dependencies
  • qemu-img
  • debootstrap
  • btrfs-progs
  • rsync
  • tar
  • xz

How to build these images ?

Firstly, install distrobuilder:

$ snap install distrobuilder --classic [--edge]

If you don't want to use snap, I also have created an OCI image for running Distrobuilder builds inside a container (Docker or rootful Podman):

$ docker pull ghcr.io/f-bn/distrobuilder:edge
$ alias distrobuilder="docker run -ti --rm --net=host --privileged -v $PWD:/build --tmpfs /var/cache:rw,exec,dev ghcr.io/f-bn/distrobuilder:edge"

Note: above system packages requirements doesn't apply when using distrobuilder in a container as everything is bundled into the image

Once distrobuilder is installed, you can build the image:

• Container image

  distrobuilder build-incus ubuntu.yml [options]

• Virtual machine image

  You need to add a --vm flag in order to build a virtual machine image :

  distrobuilder build-incus ubuntu.yml --vm [options]

• Choose a distribution release version

  # Ubuntu
  distrobuilder build-incus ubuntu.yml -o image.release=jammy [options]

• Use a tmpfs for build cache

  It can be interesting to use a tmpfs to speed up the build and preserve SSDs if a lot of image builds are planned :

  mkdir -p /var/cache/distrobuilder/build
  mount -t tmpfs -o rw,size=4G,uid=0,gid=0,mode=1755 tmpfs /var/cache/distrobuilder/build

  Build the image by specifying the tmpfs cache directory :

  distrobuilder build-incus ubuntu.yml --cache-dir=/var/cache/distrobuilder/build

How to build a Talos Linux image ?

In order to build an Incus-compatible Talos Linux image (unified tarball format), a script is available to automate the build steps from official Talos Linux nocloud raw images.

$ ./bin/build-talos-image.sh
* Downloading Talos Linux image (1.8.1)...
* Extracting image...
* Convert image to QCOW2 format...
    (100.00/100%)
* Create Incus unified tarball...
* Cleaning up...

You can also specify the Talos Linux version (using GitHub tag):

$ ./bin/build-talos-image.sh v1.9.0-alpha.0

Once the build is done, you can find a talos-<version>.tar.zst archive in the output/ directory that you can import into Incus:

$ ls -lh output/
total 99M
-rw-r--r-- 1 f-bn f-bn 99M Oct 21 15:50 talos-v1.8.1.tar.zst

$ incus image import output/talos-v1.8.1.tar.zst --alias talos/1.8.1
$ incus image info talos/1.8.1
Fingerprint: <fingerpint>
Size: 98.32MiB
Architecture: x86_64
Type: virtual-machine
Public: no
Timestamps:
    Created: 2024/10/21 01:51 UTC
    Uploaded: 2024/10/21 01:51 UTC
    Expires: never
    Last used: 0001/01/01 00:00 UTC
Properties:
    description: Talos Linux 1.8.1
    os: Talos Linux
    release: 1.8.1
Aliases:
    - talos/1.8.1
Cached: no
Auto update: disabled
Profiles:
    - default
$ incus launch talos/1.8.1 v1 --vm -c security.secureboot=false --console
...
EFI stub: Loaded initrd from LINUX_EFI_INITRD_MEDIA_GUID device path
[    0.000000] Linux version 6.6.54-talos (@buildkitsandbox) (gcc (GCC) 13.3.0, GNU ld (GNU Binutils) 2.43.1) #1 SMP Mon Oct  7 18:53:44 UTC 2024
[    0.000000] Command line: BOOT_IMAGE=/A/vmlinuz talos.platform=nocloud console=tty1 console=ttyS0 net.ifnames=0 init_on_alloc=1 slab_nomerge pti=on consoleblank=0 nvme_core.io_timeout=4294967295 printk.devkmsg=on ima_templat
e=ima-ng ima_appraise=fix ima_hash=sha512

References

• Linux Containers: https://linuxcontainers.org/
• Incus: https://github.com/lxc/incus
• Distrobuilder: https://github.com/lxc/distrobuilder
• Talos Linux: https://www.talos.dev/