hypersolid

build a custom debian image with multistrap into a single squasfs-file with tmpfs overlay

NOTE: this buildsystem is targeted to advanced/professional users with a several years of experience with linux/debian/docker only!

DO NOT USE THIS SYSTEM/IMAGES AS BEGINNER

Features

3 File - full featured - Debian Linux
Build a full customized debian image from scratch
Multistrap based bootstrapping
rootfs wrapped into single squashfs file
Immutable filesystem (squashfs base with tmpfs overlay via overlayfs)
Persistent storage option (additional overlayfs base)
Build environment is isolated within a systemd-nspawn container
Minimal system including systemd and networking
Multiple build hooks to run custom scripts during build process
Hooks for setup/signing/deployment tasks
Initramfs creation
CLI mode (no GUI)

Devices / Use Cases

Create highly customizable and fully immutable images for:

Bare metal servers
Cloud servers
Workstations
Fat-clients / thin-clients
IoT devices
Firewall/Networkworking equipment
Embedded Systems

Target platforms

Generic baremetal systems - multiarch
Generic virtualized maschines (kvm/quemu) - multiarch

embedded

Build System Requirements

Debian Linux based Host System
Host System with enabled binfmt-support (for qemu armel emulation)
Active Internet connection to fetch the packages or local package server
Recommended: apt-cacher-ng within your network or hostsystem
sudo to run systemd-nspawn as user
~450MB disk space for the build system
~5GB disk space for the target system

Build System Dependencies

apt-get install sudo systemd-container multistrap binfmt-support qemu-user-static

sudo for systemd-nspawn

# create group with sudo access to systemd-nspawn
groupadd nspawn

# assign group to your build user
usermod -a -G nspawn myBuildUser

File /etc/sudoers.d/nspawn

%nspawn ALL=(root) NOPASSWD:/usr/bin/systemd-nspawn

Usage

Run hypersolid.sh build <targetdir>

Build

$ ./hypersolid build targets/raspberrypi-zero-w/

How it works

An isolated debian environment it created in /tmp/hypersolid-env via multistrap
The build content (rootfs, scripts, multistrap config) is copied into /tmp/hypersolid-env/build/*
STAGE-1 multistrap is invoked within the build-env to build the base system in <hypersolid-env>/build/target | systemd-nspawn in <hypersolid-env>
STAGE-2 package configuration dpkg --configure is executed within the target environment | systemd-nspawn in <hypersolid-env>/build/target
STAGE-3 squashfs/cpio images are created and kernel+initramfs are copied into <hypersolid-env>/build/dist | systemd-nspawn in <hypersolid-env>

Directories

/tmp/hypersolid-env - the isolated build system
<hypersolid-env>/build/rootfs - merged rootfs (hypersolid generic + target)
<hypersolid-env>/build/target - the multistrap chroot containing the final system
<hypersolid-env>/build/dist - output directory including the kernel+initramfs+system image and optional file

License

hypersolid is OpenSource and licensed under the Terms of GNU General Public Licence v2. You're welcome to contribute!

hypersolid-os/hypersolid