Distrobuilder

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distrobuilder is an integration tool used to create LXC or LXD container images. It takes a YAML-formatted configuration file as input and generates compressed image files which can be imported to a local repository or provided remotely via a repository server.

Installation

Kernel

distrobuilder requires overlay filesystem support in order to work.

KERNEL Enable CONFIG_OVERLAY_FS for distrobuilder
File systems  --->    
  <*> Overlay filesystem support

USE flags

USE flags for app-containers/distrobuilder System container image builder for LXC and LXD

verify-sig Verify upstream signatures on distfiles
Data provided by the Gentoo Package Database · Last update: 2023-08-13 07:13 More information about USE flags

Emerge

root #emerge --ask app-emulation/distrobuilder

Additional software

app-emulation/distrobuilder does not include any YAML templates. The upstream templates can be a useful guide when generating custom images. They may be found at github.com/lxc/lxc-ci.

Usage

Like docker, distrobuilder builds images by following definitions from a YAML file.

The YAML template

The upstream Gentoo templates are intentionally kept very slim. What follows are some sensible improvements.

Managing packages

Package management is determined by the packages: section:

CODE Example of packages section
packages:
  manager: portage
  update: false
  cleanup: true
  sets:
    - packages:
        - cloud-init
      action: install
      variants:
        - cloud
    - packages:
        - gentoo-kernel-bin
        - grub
        - syslog-ng
        - sys-power/acpid
      action: install
      types:
        - vm
  • packages: demarcates the section.
  • manager: tells distrobuilder what package manager the image uses. portage is predefined.
  • update: If set to true, all installed packages are updated at the time the image is created. The upstream templates use the stage 3 tarball and have update: false, which means the repo directory in the container is empty and portage will fail. To avoid this, set update: true. Please note, setting update: true will make the image larger.
  • cleanup: If set to true, the package manager will perform a cleanup operation to which usually cleans up cached files. It is not clear what operation this makes portage perform.
  • sets: Contains a list of packages following a bullet point - and the keyword remove, an action:, and optional filters such as variants and types. The packages are defined using standard portage package atoms; action: must be set to either install or remove. The types determine whether a container or a virtual machine is built; this is set via a switch to distrobuilder at the time of image creation. Similarly, variants allow different configurations based on the same base template.
CODE 
packages:
  manager: portage
  update: true
  cleanup: true
  sets:
    - packages:
        - sys-apps/portage
        - www-servers/nginx
        - net-misc/openssh
        - app-portage/eix
        - app-editors/vim
        - app-portage/gentoolkit
        - app-portage/portage-utils
        - app-admin/eselect
        - sys-apps/mlocate
        - app-admin/sysklogd
      action: install
    - packages:
        - cloud-init
      action: install
      variants:
        - cloud
    - packages:
        - gentoo-kernel-bin
        - grub
        - syslog-ng
        - sys-power/acpid
      action: install
      types:
        - vm

Create your own container images

You can create your own container images based on Gentoo's downloadable stages. You can control the image variant with -o source.variant option, initd variant with -o image.variant, and architecture with -o image.architecture. See examples below.

Note
See https://github.com/lxc/lxc-ci/blob/master/images/gentoo.yaml for latest available yaml config which we're using.

For each example below create or download gentoo.yaml:

user $mkdir -p ~/distrobuilder/gentoo
user $cd ~/distrobuilder/gentoo

Example: LLVM container

To create an llvm container for example, follow these steps:

user $cd ~/distrobuilder/gentoo
user $mkdir llvm
user $cd llvm

distrobuilder requires a root access, straight by suing or sudoing, because it needs access to /dev etc.

root #distrobuilder build-lxd ../gentoo.yaml -o image.architecture=amd64 -o image.variant=openrc -o source.variant=llvm-openrc
user $lxc image import lxd.tar.xz rootfs.squashfs --alias gentoo-amd64-llvm
user $lxc launch gentoo-amd64-llvm gentoo-llvm-test
user $lxc exec gentoo-llvm-test bash

For an x86 arch testing container on amd64, just specify architecture:

root #distrobuilder build-lxd ../gentoo.yaml -o image.architecture=x86 -o image.variant=openrc -o source.variant=openrc

Example: musl container

To get a musl container you have to edit the gentoo.yaml config file, removing locale-gen command in post-unpack action section since musl doesn't have it.

user $cd ~/distrobuilder/gentoo
user $mkdir musl
user $cd musl
user $cp ../gentoo.yaml .
user $vim gentoo.yaml # edit gentoo.yaml by removing locale-gen command
root #sudo distrobuilder build-lxd ./gentoo.yaml -o image.architecture=amd64 -o image.variant=openrc -o source.variant=musl
user $lxc image import lxd.tar.xz rootfs.squashfs --alias gentoo-amd64-musl
user $lxc launch gentoo-amd64-musl gentoo-musl-test
user $lxc exec gentoo-musl-test bash

See Also

Retrieved from "https://wiki.gentoo.org/index.php?title=Distrobuilder&oldid=1253801"