BDEBSTRAP

NAME

bdebstrap - YAML config based multi-mirror Debian chroot creation tool

SYNOPSIS

bdebstrap [-h|--help] [-c|--config CONFIG] [-n|--name NAME] [-e|--env ENV] [-s|--simulate|--dry-run] [-b|--output-base-dir OUTPUT_BASE_DIR] [-o|--output OUTPUT] [-q|--quiet|--silent|-v|--verbose|--debug] [-f|--force] [-t|--tmpdir TMPDIR] [--variant {extract,custom,essential,apt,required,minbase,buildd,important,debootstrap,-,standard}] [--mode {auto,sudo,root,unshare,fakeroot,fakechroot,proot,chrootless}] [--format {auto,directory,dir,tar,squashfs,sqfs,ext2,null}] [--aptopt APTOPT] [--keyring KEYRING] [--dpkgopt DPKGOPT] [--hostname HOSTNAME] [--install-recommends] [--packages|--include PACKAGES] [--components COMPONENTS] [--architectures ARCHITECTURES] [--setup-hook COMMAND] [--essential-hook COMMAND] [--customize-hook COMMAND] [--cleanup-hook COMMAND] [--suite SUITE] [--target TARGET] [--mirrors MIRRORS] [SUITE [TARGET [MIRROR...]]]

DESCRIPTION

bdebstrap creates a Debian chroot of SUITE into TARGET from one or more MIRRORs and places meta-data in the OUTPUT directory: A config.yaml containing the configuration for the build (useful for rebuilds) and a manifest listing all installed packages and versions. If TARGET is just a filename (and not include the path), it will be placed in the OUTPUT directory as well. bdebstrap extents mmdebtrap to make it configurable via YAML configuration files for more complex builds.

The configuration parameters can be passed to bdebstrap as command line arguments or in one or more configuration YAML files. The content of YAML files will be merged by appending lists and recursively merging maps. Arguments specified on the command line will take precedence over values provided in the YAML configuration file. The final merged parameters will be stored in the output directory as config.yaml.

OPTIONS

-h, --help

Show a help message and exit

-c CONFIG, --config CONFIG

Configuration YAML file. See YAML CONFIGURATION below for the expected structure of this file. This parameter can be specified multiple times. The content of YAML files will be merged by appending lists and recursively merging maps.

-n NAME, --name NAME

name of the generated golden image. If no output directory is specified, the golden image will be placed in OUTPUT_BASE_DIR/NAME.

-e ENV, --env ENV

Add an additional environment variable. These environment variable will be set when calling the hooks.

-s, --simulate, --dry-run

Run apt-get with --simulate. Only the package cache is initialized but no binary packages are downloaded or installed. Use this option to quickly check whether a package selection within a certain suite and variant can in principle be installed as far as their dependencies go. If the output is a tarball, then no output is produced. If the output is a directory, then the directory will be left populated with the skeleton files and directories necessary for apt to run in it.

-b OUTPUT_BASE_DIR, --output-base-dir OUTPUT_BASE_DIR

output base directory. By default it is the current directory.

-o OUTPUT, --output OUTPUT

output directory (default: output-base-dir/name)

-q, --quiet, --silent

Do not write anything to standard error except errors. If used together with --verbose or --debug, only the last option will take effect.

-v, --verbose

Write informational messages (about configuration files, environment variables, mmdebstrap call, etc.) to standard error. Instead of progress bars, mmdebstrap writes the dpkg and apt output directly to standard error. If used together with --quiet or --debug, only the last option will take effect.

--debug

In addition to the output produced by --verbose, write detailed debugging information to standard error. Errors of mmdebstrap will print a backtrace. If used together with --quiet or --verbose, only the last option will take effect.

-f, --force

Remove existing output directory before creating a new one

-t TMPDIR, --tmpdir TMPDIR

Temporary directory for building the image (default: /tmp)

--variant
{extract,custom,essential,apt,required,minbase,buildd,important,debootstrap,-,standard}

Choose which package set to install.

--mode {auto,sudo,root,unshare,fakeroot,fakechroot,proot,chrootless}

Choose how to perform the chroot operation and create a filesystem with ownership information different from the current user.

[--format {auto,directory,dir,tar,squashfs,sqfs,ext2,null}

Choose the output format.

--aptopt APTOPT

Pass arbitrary options or configuration files to apt.

--keyring KEYRING

Change the default keyring to use by apt.

--dpkgopt DPKGOPT

Pass arbitrary options or configuration files to dpkg.

--hostname HOSTNAME

Write the given HOSTNAME into /etc/hostname in the target chroot.

--install-recommends

Consider recommended packages as a dependency for installing.

--packages PACKAGES, --include PACKAGES

Comma or whitespace separated list of packages which will be installed in addition to the packages installed by the specified variant.

--components COMPONENTS

Comma or whitespace separated list of components like main, contrib and non-free which will be used for all URI-only MIRROR arguments.

--architectures ARCHITECTURES

Comma or whitespace separated list of architectures. The first architecture is the native architecture inside the chroot.

--setup-hook COMMAND

Execute arbitrary COMMAND right after initial setup (directory creation, configuration of apt and dpkg, ...) but before any packages are downloaded or installed. At that point, the chroot directory does not contain any executables and thus cannot be chroot-ed into. This option can be specified multiple times.

--essential-hook COMMAND

Execute arbitrary COMMAND after the Essential:yes packages have been installed, but before installing the remaining packages. This option can be specified multiple times.

--customize-hook COMMAND

Execute arbitrary COMMAND after the chroot is set up and all packages got installed but before final cleanup actions are carried out. This option can be specified multiple times.

--cleanup-hook COMMAND

Execute arbitrary COMMAND after all customize hooks have been executed. This option can be specified multiple times.

--suite SUITE, SUITE

The suite may be a valid release code name (eg, sid, stretch, jessie) or a symbolic name (eg, unstable, testing, stable, oldstable).

--target TARGET, TARGET

The optional target argument can either be the path to a directory, the path to a tarball filename, the path to a squashfs image or -.

--mirrors MIRRORS, MIRRORS

Comma separated list of mirrors. If no mirror option is provided, http://deb.debian.org/debian is used.

YAML CONFIGURATION

This section describes the expected data-structure hierarchy of the YAML configuration file(s). The top-level structure is expected to be a mapping. The top-level mapping may contain following keys:

env

mapping of environment variables names to their values. Environment variables can be overridden by specifying them with --env using the same name. These environment variable are set before calling the hooks.

name

String. Name of the generated golden image. Can be overridden by --name.

mmdebstrap

mapping. The values here are passed to mmdebstrap(1). Following keys might be specified:
aptopts

list of arbitrary options or configuration files (string) to apt. Additional apt options can be specified with --aptopt.

architectures

list of architectures (string). The first architecture is the native architecture inside the chroot. Additional architectures can be specified with --architectures.

components

list of components (string) like main, contrib and non-free which will be used for all URI-only MIRROR arguments. Additional components can be specified with --components.

dpkgopts

list of arbitrary options or configuration files (string) to dpkg. Additional dpkg options can be specified with --dpkgopt.

format

Choose the output format. It needs to be one of auto, directory, dir, tar, squashfs, sqfs, ext2, null. See mmdebstrap(1) for details. Can be overridden by --format.

hostname

String. If specified, write the given hostname into /etc/hostname in the target chroot. This parameter does not exist in mmdebstrap and is implemented as customize hook for mmdebstrap. Can be overridden by --hostname.

install-recommends

Boolean. If set to True, the APT option Apt::Install-Recommends “true” is passed to mmdebstrap via --aptopt. Can be overridden by --install-recommends.

keyrings

list of default keyring to use by apt. Additional keyring files can be specified with --keyring.

mirrors

list of mirrors (string). Additional mirrors can be specified with --mirrors.

mode

Choose how to perform the chroot operation and create a filesystem with ownership information different from the current user. It needs to be one of auto, sudo, root, unshare, fakeroot, fakechroot, proot, or chrootless. See mmdebstrap(1) for details. Can be overridden by --mode.

packages

list of packages (string) which will be installed in addition to the packages installed by the specified variant. Additional packages can be specified with --packages or --include. This setting is passed to mmdebstrap using the --include parameter.

setup-hooks

list of setup hooks (string). Execute arbitrary commands right after initial setup (directory creation, configuration of apt and dpkg, ...) but before any packages are downloaded or installed. At that point, the chroot directory does not contain any executables and thus cannot be chroot-ed into. See HOOKS in mmdebstrap(1) for more information and examples. Additional setup hooks can be specified with --setup-hook.

essential-hooks

list of essential hooks (string). Execute arbitrary commands after the Essential:yes packages have been installed, but before installing the remaining packages. See HOOKS in mmdebstrap(1) for more information and examples. Additional essential hooks can be specified with --essential-hook.

customize-hooks

list of customize hooks (string). Execute arbitrary commands after the chroot is set up and all packages got installed but before final cleanup actions are carried out. See HOOKS in mmdebstrap(1) for more information and examples. Additional customize hooks can be specified with --customize-hook.

cleanup-hooks

list of cleanup hooks (string). Cleanup hooks are just hooks that are run directly after all other customize hooks. See customize-hooks above. Additional cleanup hooks can be specified with --cleanup-hook.

suite

String. The suite may be a valid release code name (eg, sid, stretch, jessie) or a symbolic name (eg, unstable, testing, stable, oldstable). Can be overridden by --suite.

target

String. The target argument can either be the path to a directory, the path to a tarball filename, the path to a squashfs image or -. Can be overridden by --target.

variant

Choose which package set to install. It needs to be one of extract, custom, essential, apt, required, minbase, buildd, important, debootstrap, -, standard. See mmdebstrap(1) for details. Can be overridden by --variant.

HOOKS

bdebstrap enhances the hooks provided by mmdebstrap. Hooks can use the environment variables specified via the env configuration option or the --env parameter. bdebstrap sets following environment variables by default to be consumed by the hooks:
BDEBSTRAP_HOOKS

Path to the hooks provided by bdebstrap.

BDEBSTRAP_NAME

name of the generated golden image which is set via the name configuration option of the --name parameter.

BDEBSTRAP_OUTPUT_DIR

Path of a temporary directory inside the chroot. Files and directories that are placed inside this directory will be copied out of the image into the output directory. This temporary directory will be removed in a final cleanup hook.

Following hook scripts are shipped with bdebstrap:
disable-units

Disable services / systemd units.

enable-units

Enable services / systemd units.

Example usage for the hook scripts:

---
mmdebstrap:
customize-hooks:
- $BDEBSTRAP_HOOKS/disable-units "$1" apt-daily.timer cron
- $BDEBSTRAP_HOOKS/enable-units "$1" systemd-timesyncd
suite: bullseye
target: root.tar
variant: important

EXAMPLES

Minimal Debian unstable tarball

This example shows how to use a small YAML configuration to build a minimal Debian unstable tarball. Assume following configuration is stored in unstable.yaml:

---
mmdebstrap:
keyrings:
- /usr/share/keyrings/debian-archive-keyring.gpg
mode: unshare
suite: unstable
target: root.tar.xz
variant: minbase

Then the tarball can be generated by running

$ bdebstrap -c unstable.yaml --name example1
$ ls example1/
config.yaml manifest root.tar.xz

Debian live system

This example shows how to use a YAML configuration to build a Debian 11 (bullseye) live system. Assume following configuration is stored in live.yaml:

---
mmdebstrap:
architectures:
- amd64
cleanup-hooks:
- cp /dev/null "$1/etc/hostname"
- if test -f "$1/etc/resolv.conf"; then cp /dev/null "$1/etc/resolv.conf"; fi
customize-hooks:
- cp --preserve=timestamps -v "$1"/boot/vmlinu* "$1${BDEBSTRAP_OUTPUT_DIR?}/vmlinuz"
- cp --preserve=timestamps -v "$1"/boot/initrd.img* "$1${BDEBSTRAP_OUTPUT_DIR?}/initrd.img"
- mkdir -p "$1/root/.ssh"
- upload ~/.ssh/id_rsa.pub /root/.ssh/authorized_keys
keyrings:
- /usr/share/keyrings/debian-archive-keyring.gpg
mode: unshare
packages:
- init
- iproute2
- less
- libpam-systemd
- linux-image-cloud-amd64
- live-boot
- locales
- openssh-server
suite: bullseye
target: root.squashfs
variant: minbase

This example assumes that ~/.ssh/id_rsa.pub exists, because it will be copied into the image to /root/.ssh/authorized_keys to allow SSH access using the user’s SSH key.

The squashfs image can be generated by running

$ bdebstrap -c live.yaml --name example2
$ ls example2/
config.yaml initrd.img manifest root.squashfs vmlinuz

The kernel and initrd are copied out of the squashfs image using customize hooks to allow them to be used directly by QEMU. To launch this image locally with QEMU, the root.squashfs image needs to be provided by a HTTP server:

$ python3 -m http.server -b localhost --directory example2 8080

This command exposes the generated image via HTTP on localhost on port 8080. QEMU can be started passing the TCP traffic on port 8080 to the webserver:

$ cd example2
$ qemu-system-x86_64 -machine accel=kvm -m 1G -device virtio-net-pci,netdev=net0 -monitor vc \
-netdev user,id=net0,hostfwd=tcp::2222-:22,guestfwd=tcp:10.0.2.252:8080-tcp:localhost:8080,hostname=debian-live \
-kernel ./vmlinuz -initrd ./initrd.img -append "boot=live fetch=http://10.0.2.252:8080/root.squashfs quiet"

To print the output on the launching terminal, add -nographic -serial stdio to the QEMU command line and console=ttyS0 to the -append parameter. Once the virtual machine is started, it can be accessed via SSH:

$ ssh -oUserKnownHostsFile=/dev/null -oStrictHostKeyChecking=no -p 2222 root@localhost

SEE ALSO

mmdebstrap(1), debootstrap(8)

AUTHOR

Benjamin Drung <bdrung@posteo.de>