Mmdebstrap

mmdebstrap

mmdebstrap is a efficient tool designed to create minimal Debian-based system images or root filesystems. It serves as an alternative to the traditional debootstrap tool, offering several advantages in terms of speed, flexibility, and functionality. Unlike debootstrap, which resolves dependencies in a straightforward manner, mmdebstrap leverages the apt package manager to handle dependencies. This allows it to use multiple mirrors, resolve complex dependencies, and customize the sources list dynamically. The tool supports creating chroot environments for various use cases, including containers, virtual machines, embedded systems, and even custom live systems.

Features and Advantages

mmdebstrap has this ability to create lightweight and minimal chroot environments by installing only essential packages or by customizing the package selection based on user requirements. This makes it particularly useful for developers, testers, and system administrators who need isolated environments for software testing or package development without affecting their primary systems. Additionally, it supports creating reproducible builds by setting the SOURCE_DATE_EPOCH environment variable, ensuring consistency across multiple runs.

Preparing Root Filesystems

When it comes to preparing root filesystems (fsroot), mmdebstrap is good for simplicity and efficiency. It can generate a root filesystem in various formats, such as directories or compressed tarballs, depending on the specified output target. For example, users can invoke mmdebstrap with specific options to produce a minimal root filesystem tailored for embedded devices or IoT systems. The tool also supports adding custom packages or repositories during the build process, allowing for extensive customization of the generated filesystem.

Operational Flexibility

mmdebstrap is designed to work in environments with limited privileges. It can operate without root permissions by using the Linux user namespaces or fakechroot, making it safe and accessible for non-administrative users. This feature is particularly beneficial for creating chroot tarballs in secure environments where elevated privileges are restricted.

Practical Usage

In practice, using mmdebstrap to prepare an fsroot involves specifying the desired Debian release (e.g., "stable" or "sid"), the output format (e.g., directory or tarball), and optional mirrors for package sources. The tool downloads and installs the required packages into a temporary directory or directly into the target filesystem. For instance, when generating a root filesystem for a specific device like a Banana Pi board, additional steps may include configuring partitions, formatting storage devices, and extracting the generated filesystem onto the target hardware.

Overall, mmdebstrap simplifies the process of creating minimal and customized Debian-based root filesystems while offering advanced features like multi-mirror support, reproducibility, and non-root operation. These capabilities make it an valuable tool for system preparation in diverse scenarios ranging from development and testing to deployment on embedded platforms.

Example

import subprocess
import os
import shutil

def create_devuan_chroot(target_dir):
    """
    Make sure the target directory exists and is empty, then set the Devuan
    Daedalus repository, define the command list to run mmdebstrap,
    and finally run mmdebstrap.
    """
    if os.path.exists(target_dir):
        shutil.rmtree(target_dir)
    os.makedirs(target_dir, exist_ok=True)
    repo = "deb http://deb.devuan.org/merged daedalus main"
    cmd = [
        'sudo',
        'mmdebstrap',
        '--include=' + (
            'apt,base-files,devuan-keyring,dpkg,init,kmod,libc6,'
            'libgcc-s1,libstdc++6,procps,sysvinit-core,coreutils,'
            'bash,grep,gzip,sed,tar'
        ),
        '--architectures=amd64',
        'daedalus',
        target_dir,
        'http://deb.devuan.org/merged'
    ]
    try:
        subprocess.run(cmd, check=True)
        print(f"Devuan Daedalus chroot created successfully in {target_dir}")
    except subprocess.CalledProcessError as _:
        print(f"Error creating chroot: {_}")

# Run the function with your path
create_devuan_chroot("/Set/Path/To/Your/workingfolder.")

mmdebstrap repo

You can find the repo here: https://salsa.debian.org/debian/mmdebstrap