Alpine Linux USB Rescue ISO

A bootable hybrid ISO that:

Gets an IP via DHCP on eth0
Automatically opens a Nebula overlay tunnel
Runs OpenSSH (login: root / alpine)
Carries all tools needed to install Alpine onto the host machine (setup-alpine, setup-disk, parted, …)

The ISO is a hybrid image — it can be written to a USB stick with dd or burned to a CD/DVD.

Prerequisites

Docker + Docker Compose
A Nebula certificate set for this node (see below)

1. Place Nebula certificates

Put the following files in nebula/:

nebula/
  nebula       ← binary (already included)
  config.yml   ← already included, edit as needed
  ca.crt       ← your Nebula CA certificate  ← YOU PROVIDE
  host.crt     ← this node's certificate     ← YOU PROVIDE
  host.key     ← this node's private key     ← YOU PROVIDE

ca.crt, host.crt, and host.key are gitignored.

2. Build the ISO

docker compose run --rm alpine bash /scripts/create.sh

The ISO is written to output/rescue-alpine.iso.

3. Write to USB

dd if=output/rescue-alpine.iso of=/dev/sdX bs=4M status=progress && sync

Replace /dev/sdX with your USB device (check with lsblk). All data on the device will be erased.

Or burn to CD/DVD:

cdrecord dev=/dev/sr0 output/rescue-alpine.iso

4. Boot and connect

Insert USB and boot the target machine from it.
The system comes up fully in RAM — no writes to the host disk.
On boot, eth0 gets an IP via DHCP, then the Nebula tunnel comes up automatically.
SSH in via the Nebula overlay IP (see nebula/config.yml):

ssh root@<nebula-ip>
# password: alpine

5. Install Alpine onto the host machine

Once SSH'd in (or at the local console):

# Interactive guided installer — partitions disk, installs Alpine
setup-alpine

# Or use setup-disk for more control
setup-disk -m sys /dev/sda

All required tools (parted, e2fsprogs, dosfstools, btrfs-progs, alpine-conf, …) are pre-installed.

Default credentials

Field	Value
Username	`root`
Password	`alpine`

Change this in scripts/chroot-setup.sh before building if needed.

Architecture

ISO (hybrid — bootable on USB or CD)
└── isolinux (BIOS boot)
    ├── vmlinuz-lts
    └── initramfs.gz   ← entire Alpine system packed as cpio+gzip
        ├── eth0 DHCP  (openrc networking)
        ├── nebula      → /usr/local/bin/nebula
        ├── /etc/nebula/ (config + certs)
        ├── OpenSSH (sshd)
        └── Alpine install tools

The system runs entirely in RAM — the host disk is never touched until you explicitly run the installer.

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