feat: Implement complete Zero OS Alpine Initramfs Builder

- Complete bash framework with strict error handling
- Modular library system (docker, alpine, components, initramfs, kernel, testing)
- Rust component integration (zinit, rfs, mycelium) with musl targeting
- Rootless Docker/Podman support for GitHub Actions
- Centralized configuration in config/build.conf
- 2-stage module loading system
- Strip + UPX optimization for minimal size
- Complete zinit integration replacing OpenRC
- GitHub Actions CI/CD pipeline
- Comprehensive documentation and usage guides

Components:
- Latest stable kernel 6.12.44
- Alpine Linux 3.22 base
- ThreeFold components: zinit, mycelium, rfs, corex
- Target: ~8-12MB final initramfs.cpio.xz

configs/init

@@ -0,0 +1,103 @@
+#!/bin/sh
+# Alpine-based Zero-OS Init Script
+# Maintains identical flow to original busybox version
+
+echo ""
+echo "============================================"
+echo "==       ZERO-OS ALPINE INITRAMFS        =="
+echo "============================================"
+
+echo "[+] creating ram filesystem"
+mount -t proc proc /proc
+mount -t sysfs sysfs /sys
+mount -t tmpfs tmpfs /mnt/root -o size=1536M
+mount -t devtmpfs devtmpfs /dev
+
+echo "[+] building ram filesystem"
+target="/mnt/root"
+
+# Copy Alpine filesystem to tmpfs (same as original)
+echo "  copying /bin..."
+cp -ar /bin $target
+echo "  copying /etc..."
+cp -ar /etc $target
+echo "  copying /lib..."
+cp -ar /lib* $target
+echo "  copying /usr..."
+cp -ar /usr $target
+echo "  copying /root..."
+cp -ar /root $target
+echo "  copying /sbin..."
+cp -ar /sbin $target
+echo "  copying /tmp..."
+cp -ar /tmp $target
+echo "  copying /var..."
+cp -ar /var $target
+echo "  copying /run..."
+cp -ar /run $target
+
+# Create essential directories
+mkdir -p $target/dev
+mkdir -p $target/sys
+mkdir -p $target/proc
+mkdir -p $target/mnt
+
+# Mount filesystems in tmpfs
+mount -t proc proc $target/proc
+mount -t sysfs sysfs $target/sys
+mount -t devtmpfs devtmpfs $target/dev
+
+# Mount devpts for terminals
+mkdir -p $target/dev/pts
+mount -t devpts devpts $target/dev/pts
+
+echo "[+] setting environment"
+export PATH
+
+echo "[+] probing drivers"
+# Use Alpine's udev instead of busybox udevadm
+if [ -x /sbin/udevd ]; then
+    echo "  starting udevd..."
+    udevd --daemon
+    
+    echo "  triggering device discovery..."
+    udevadm trigger --action=add --type=subsystems
+    udevadm trigger --action=add --type=devices
+    udevadm settle
+    
+    echo "  stopping udevd..."
+    kill $(pidof udevd) || true
+else
+    echo "  warning: udevd not found, skipping hardware detection"
+fi
+
+echo "[+] loading essential drivers"
+# Load core drivers for storage and network
+modprobe btrfs 2>/dev/null || true
+modprobe fuse 2>/dev/null || true
+modprobe overlay 2>/dev/null || true
+
+# Load storage drivers
+modprobe ahci 2>/dev/null || true
+modprobe nvme 2>/dev/null || true
+modprobe virtio_blk 2>/dev/null || true
+modprobe virtio_scsi 2>/dev/null || true
+
+# Load network drivers  
+modprobe virtio_net 2>/dev/null || true
+modprobe e1000 2>/dev/null || true
+modprobe e1000e 2>/dev/null || true
+
+# Unmount init filesystems
+umount /proc 2>/dev/null || true
+umount /sys 2>/dev/null || true
+
+echo "[+] checking for debug files"
+if [ -e /init-debug ]; then
+    echo "  executing debug script..."
+    sh /init-debug
+fi
+
+echo "[+] switching root"
+echo "  exec switch_root /mnt/root /sbin/zinit init"
+exec switch_root /mnt/root /sbin/zinit init

configs/modules-essential.list

@@ -0,0 +1,59 @@
+# Essential kernel modules for Zero-OS Alpine initramfs
+# This file contains a curated list of essential modules for network and storage functionality
+# Comments are supported (lines starting with #)
+
+# Network drivers - Intel
+e1000
+e1000e
+igb
+ixgbe
+i40e
+ice
+
+# Network drivers - Realtek
+r8169
+8139too
+8139cp
+
+# Network drivers - Broadcom
+bnx2
+bnx2x
+tg3
+b44
+
+# Network drivers - Atheros
+atl1
+atl1e
+atl1c
+alx
+
+# VirtIO drivers
+virtio_net
+virtio_scsi
+virtio_blk
+virtio_pci
+
+# Tunnel and container support
+tun
+overlay
+
+# Storage subsystem (essential only)
+scsi_mod
+sd_mod
+
+# Control Groups (cgroups v1 and v2) - essential for container management
+cgroup_pids
+cgroup_freezer
+cgroup_perf_event
+cgroup_device
+cgroup_cpuset
+cgroup_bpf
+cgroup_debug
+memcg
+blkio_cgroup
+cpu_cgroup
+cpuacct
+hugetlb_cgroup
+net_cls_cgroup
+net_prio_cgroup
+devices_cgroup

configs/packages-minimal.txt

@@ -0,0 +1,46 @@
+# MINIMAL Alpine packages for Zero-OS embedded initramfs
+# Target: ~50MB total (not 700MB!)
+
+# Core system (essential only)
+alpine-baselayout
+busybox
+musl
+
+# Module loading & hardware detection
+eudev
+eudev-hwids
+eudev-libs
+eudev-netifnames
+kmod
+
+# Console/terminal management
+util-linux
+
+# Essential networking (for Zero-OS connectivity)
+iproute2
+ethtool
+
+# Filesystem support (minimal)
+btrfs-progs
+dosfstools
+
+# Essential libraries only
+zlib
+
+# Network utilities (minimal)
+dhcpcd
+tcpdump
+bmon
+
+# Random number generation (for crypto/security)
+haveged
+
+# SSH access and terminal multiplexer
+openssh-server
+zellij
+
+
+# Essential debugging and monitoring tools included
+# NO development tools, NO curl/wget, NO python, NO redis
+# NO massive linux-firmware package
+# Other tools will be loaded from RFS after network connectivity

configs/sources.conf

@@ -0,0 +1,10 @@
+# sources.conf - Components to download and build for initramfs
+# Format: TYPE:NAME:URL:VERSION:BUILD_FUNCTION[:EXTRA_OPTIONS]
+
+# Git repositories to clone and build
+git:zinit:https://github.com/threefoldtech/zinit:master:build_zinit
+git:mycelium:https://github.com/threefoldtech/mycelium:0.6.1:build_mycelium
+git:rfs:https://github.com/threefoldtech/rfs:development:build_rfs
+
+# Pre-built releases to download
+release:corex:https://github.com/threefoldtech/corex/releases/download/2.1.4/corex-2.1.4-amd64-linux-static:2.1.4:install_corex:rename=corex

configs/zinit/cgroup.yaml

@@ -0,0 +1,2 @@
+exec: sh /etc/zinit/init/cgroup.sh
+oneshot: true

configs/zinit/console.yaml

@@ -0,0 +1,2 @@
+exec: /sbin/getty -L 9600 console
+restart: always

configs/zinit/depmod.yaml

@@ -0,0 +1 @@
+exec: depmod -a

configs/zinit/getty.yaml

@@ -0,0 +1,2 @@
+exec: /sbin/getty -L 115200 ttyS0 vt100
+restart: always

configs/zinit/gettyconsole.yaml

@@ -0,0 +1,2 @@
+exec: /sbin/getty console linux
+restart: always

configs/zinit/haveged.yaml

@@ -0,0 +1,2 @@
+exec: haveged -w 1024 -d 32 -i 32 -v 1
+oneshot: true

configs/zinit/init/ashloging.sh

@@ -0,0 +1,6 @@
+#!/bin/bash
+
+echo "start ash terminal"
+while true; do
+    getty -l /bin/ash -n 19200 tty2
+done

configs/zinit/init/cgroup.sh

@@ -0,0 +1,10 @@
+set -x
+
+mount -t tmpfs cgroup_root /sys/fs/cgroup
+
+subsys="pids cpuset cpu cpuacct blkio memory devices freezer net_cls perf_event net_prio hugetlb"
+
+for sys in $subsys; do
+    mkdir -p /sys/fs/cgroup/$sys
+    mount -t cgroup $sys -o $sys /sys/fs/cgroup/$sys/
+done

configs/zinit/init/modprobe.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+modprobe fuse
+modprobe btrfs
+modprobe tun
+modprobe br_netfilter
+
+echo never > /sys/kernel/mm/transparent_hugepage/enabled
+
+ulimit -n 524288

configs/zinit/init/ntpd.sh

@@ -0,0 +1,10 @@
+#!/bin/sh
+
+ntp_flags=$(grep -o 'ntp=.*' /proc/cmdline | sed 's/^ntp=//')
+
+params=""
+if [ -n "$ntp_flags" ]; then
+  params=$(echo "-p $ntp_flags" | sed s/,/' -p '/g)
+fi
+
+exec ntpd -n $params

configs/zinit/init/routing.sh

@@ -0,0 +1,4 @@
+#!/bin/bash
+
+echo "Enable ip forwarding"
+echo 1 > /proc/sys/net/ipv4/ip_forward

configs/zinit/init/shm.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+mkdir /dev/shm
+mount -t tmpfs shm /dev/shm 

configs/zinit/init/sshd-setup.sh

@@ -0,0 +1,15 @@
+#!/bin/ash
+if [ -f /etc/ssh/ssh_host_rsa_key ]; then
+    # ensure existing file permissions
+    chown root:root /etc/ssh/ssh_host_*
+    chmod 600 /etc/ssh/ssh_host_*
+    exit 0
+fi
+
+echo "Setting up sshd"
+mkdir -p /run/sshd
+
+ssh-keygen -f /etc/ssh/ssh_host_rsa_key -N '' -t rsa
+ssh-keygen -f /etc/ssh/ssh_host_dsa_key -N '' -t dsa
+ssh-keygen -f /etc/ssh/ssh_host_ecdsa_key -N '' -t ecdsa -b 521
+ssh-keygen -f /etc/ssh/ssh_host_ed25519_key -N '' -t ed25519

configs/zinit/init/udev.sh

@@ -0,0 +1,4 @@
+#!/bin/sh
+
+udevadm trigger --action=add
+udevadm settle

configs/zinit/lo.yaml

@@ -0,0 +1,2 @@
+exec: ip l set lo up
+oneshot: true

configs/zinit/local-modprobe.yaml

@@ -0,0 +1,2 @@
+exec: sh /etc/zinit/init/modprobe.sh
+oneshot: true

configs/zinit/mycelium.yaml

@@ -0,0 +1,6 @@
+exec: /usr/bin/mycelium --key-file /tmp/mycelium_priv_key.bin
+  --tun-name my0 --silent --peers tcp://188.40.132.242:9651 tcp://136.243.47.186:9651
+  tcp://185.69.166.7:9651 tcp://185.69.166.8:9651 tcp://65.21.231.58:9651 tcp://65.109.18.113:9651
+  tcp://209.159.146.190:9651 tcp://5.78.122.16:9651 tcp://5.223.43.251:9651 tcp://142.93.217.194:9651
+after:
+  - network

configs/zinit/network.yaml

@@ -0,0 +1,5 @@
+exec: dhcpcd eth0
+after:
+  - depmod
+  - udevd
+  - udev-trigger

configs/zinit/ntp.yaml

@@ -0,0 +1,3 @@
+exec: sh /etc/zinit/init/ntpd.sh
+after:
+  - network

configs/zinit/routing.yaml

@@ -0,0 +1,2 @@
+exec: sh /etc/zinit/init/routing.sh
+oneshot: true

configs/zinit/shm.yaml

@@ -0,0 +1,2 @@
+exec: /etc/zinit/init/shm.sh
+oneshot: true

configs/zinit/sshd-setup.yaml

@@ -0,0 +1,2 @@
+exec: sh /etc/zinit/init/sshd-setup.sh
+oneshot: true

configs/zinit/sshd.yaml

@@ -0,0 +1,3 @@
+exec: /usr/sbin/sshd -D -e
+after:
+    - sshd-setup

configs/zinit/udev-trigger.yaml

@@ -0,0 +1,6 @@
+exec: sh /etc/zinit/init/udev.sh
+oneshot: true
+after:
+  - depmod
+  - udevmon
+  - udevd

configs/zinit/udevd.yaml

@@ -0,0 +1 @@
+exec: udevd

configs/zinit/udevmon.yaml

@@ -0,0 +1 @@
+exec: udevadm monitor