How to build images

Plain rootfs

$ distrobuilder build-dir --help
Build plain rootfs

Usage:
  distrobuilder build-dir <filename|-> <target dir> [flags]

Flags:
  -h, --help              help for build-dir
      --keep-sources      Keep sources after build (default true)
      --sources-dir       Sources directory for distribution tarballs (default "/tmp/distrobuilder")
      --with-post-files   Run post-files actions

Global Flags:
      --cache-dir         Cache directory
      --cleanup           Clean up cache directory (default true)
      --debug             Enable debug output
      --disable-overlay   Disable the use of filesystem overlays
  -o, --options           Override options (list of key=value)
  -t, --timeout           Timeout in seconds
      --version           Print version number

To build a plain rootfs, run distrobuilder build-dir. The command takes an image definition file and an output directory as positional arguments. Running build-dir is useful if one wants to build both LXC and Incus images. In that case one can simply run

distrobuilder build-dir def.yaml /path/to/rootfs
distrobuilder pack-lxc def.yaml /path/to/rootfs /path/to/output
distrobuilder pack-incus def.yaml /path/to/rootfs /path/to/output

LXC image

$ distrobuilder build-lxc --help
Build LXC image from scratch

The compression can be set with the --compression flag. I can take one of the
following values:
  - bzip2
  - gzip
  - lzip
  - lzma
  - lzo
  - lzop
  - xz (default)
  - zstd

For supported compression methods, a compression level can be specified with
method-N, where N is an integer, e.g. gzip-9.

Usage:
  distrobuilder build-lxc <filename|-> [target dir] [--compression=COMPRESSION] [flags]

Flags:
      --compression    Type of compression to use (default "xz")
  -h, --help           help for build-lxc
      --keep-sources   Keep sources after build (default true)
      --sources-dir    Sources directory for distribution tarballs (default "/tmp/distrobuilder")

Global Flags:
      --cache-dir         Cache directory
      --cleanup           Clean up cache directory (default true)
      --debug             Enable debug output
      --disable-overlay   Disable the use of filesystem overlays
  -o, --options           Override options (list of key=value)
  -t, --timeout           Timeout in seconds
      --version           Print version number

Running the build-lxc sub-command creates a LXC image. It outputs two files rootfs.tar.xz and meta.tar.xz. After building the image, the rootfs will be destroyed.

The pack-lxc sub-command can be used to create an image from an existing rootfs. The rootfs won’t be deleted afterwards.

Incus image

$ distrobuilder build-incus --help
Build Incus image from scratch

Depending on the type, it either outputs a unified (single tarball)
or split image (tarball + squashfs or qcow2 image). The --type flag can take one of the
following values:
  - split (default)
  - unified


The compression can be set with the --compression flag. I can take one of the
following values:
  - bzip2
  - gzip
  - lzip
  - lzma
  - lzo
  - lzop
  - xz (default)
  - zstd

For supported compression methods, a compression level can be specified with
method-N, where N is an integer, e.g. gzip-9.

Usage:
  distrobuilder build-incus <filename|-> [target dir] [--type=TYPE] [--compression=COMPRESSION] [--import-into-incus] [flags]

Flags:
      --compression               Type of compression to use (default "xz")
  -h, --help                      help for build-incus
      --import-into-incus[="-"]   Import built image into Incus
      --keep-sources              Keep sources after build (default true)
      --sources-dir               Sources directory for distribution tarballs (default "/tmp/distrobuilder")
      --type                      Type of tarball to create (default "split")
      --vm                        Create a qcow2 image for VMs

Global Flags:
      --cache-dir         Cache directory
      --cleanup           Clean up cache directory (default true)
      --debug             Enable debug output
      --disable-overlay   Disable the use of filesystem overlays
  -o, --options           Override options (list of key=value)
  -t, --timeout           Timeout in seconds
      --version           Print version number

Running the build-incus sub-command creates an Incus image. If --type=split, it outputs two files. The metadata tarball will always be named incus.tar.xz. When creating a container image, the second file will be rootfs.squashfs. When creating a VM image, the second file will be disk.qcow2. If --type=unified, a unified tarball named <image.name>.tar.xz is created. See the image section for more on the image name.

If --compression is set, the tarballs will use the provided compression instead of xz.

Setting --vm will create a qcow2 image which is used for virtual machines.

If --import-into-incus is set, the resulting image is imported into Incus. It basically runs lxc image import <image>. Per default, it doesn’t create an alias. This can be changed by calling it as --import-into-incus=<alias>.

After building the image, the rootfs will be destroyed.

The pack-incus sub-command can be used to create an image from an existing rootfs. The rootfs won’t be deleted afterwards.