Dotfiles/docs/md/archiso.md

171 lines
5.1 KiB
Markdown

# Archiso — Custom Live Installer
The archiso build system produces a bootable Arch Linux ISO pre-loaded with the M-Archy installer scripts. Optionally, an answerfile can be embedded so the entire install — base OS + dotfiles — runs with zero user interaction.
---
## Prerequisites
```bash
sudo pacman -S archiso jq
```
---
## Building the ISO
```bash
# Basic build — interactive installer, no answerfile
bash setup/archiso/build.sh
# Specify output directory
bash setup/archiso/build.sh /path/to/output
# Embed an answerfile for automated deployment
bash setup/archiso/build.sh --preconf
# Embed a specific answerfile
bash setup/archiso/build.sh --preconf ~/my-server.json
# Both flags together
bash setup/archiso/build.sh --preconf ~/my-server.json /media/usb/output
```
| Flag | Effect |
|------|--------|
| _(none)_ | Clean ISO, no answerfile |
| `--preconf` | Embed `~/answerfile.json` at `/answerfile.json` in the ISO |
| `--preconf FILE` | Embed the specified file instead |
Build artefacts land in `~/m-archy-out/` by default. Override with the `OUT_DIR` environment variable or by passing a path argument.
### Environment Variables
| Variable | Default | Purpose |
|----------|---------|---------|
| `WORK_DIR` | `~/m-archy-build` | Scratch space for mkarchiso |
| `OUT_DIR` | `~/m-archy-out` | ISO output directory |
---
## What the Build Does
1. Copies the upstream `releng` Arch base profile
2. Applies the M-Archy overlay (`setup/archiso/overlay/`)
3. Replaces `profiledef.sh` with the M-Archy version
4. Adds extra packages from `packages.extra`
5. Embeds both installer scripts (`arch-autoinstall.sh`, `archbaseos-guided-install.sh`) into `/root/installer/`
6. If `--preconf`: copies the answerfile to `/answerfile.json` in the ISO's airootfs
7. Runs `mkarchiso` to produce the final `.iso`
---
## Extra Packages on the Live System
Defined in `setup/archiso/overlay/packages.extra`:
```
git
jq
pam-u2f
btop
fastfetch
openssh
```
These are added on top of the standard Arch `releng` package set.
---
## Live System Entry Points
Once booted from the ISO, the following are available:
### `install-arch`
A command placed in `/usr/local/bin/`:
```bash
install-arch # guided mode (default)
install-arch guided # guided interactive install
install-arch auto # automated mode (reads /answerfile.json)
```
### `/root/launch.sh`
Internal dispatcher used by `install-arch`.
### `/answerfile.json`
Only present when built with `--preconf`. Both installer scripts check for this file on startup. If found, all prompts are answered from it — the only interaction required is the disk-encryption password (passwords are never stored in answerfiles).
---
## Automated Deployment Workflow
```
┌─────────────────────────────────────┐
│ Developer machine │
│ │
│ 1. generate-answerfile.sh │
│ → ~/answerfile.json │
│ │
│ 2. build.sh --preconf │
│ → ~/m-archy-out/m-archy.iso │
│ │
│ 3. dd if=m-archy.iso of=/dev/sdX │
└──────────────┬──────────────────────┘
│ USB
┌─────────────────────────────────────┐
│ Target machine (boots from USB) │
│ │
│ 4. install-arch auto │
│ reads /answerfile.json │
│ installs base OS │
│ runs tui-install.sh in chroot │
│ installs dotfiles & apps │
│ │
│ 5. Reboot → ready system │
└─────────────────────────────────────┘
```
For multi-machine deployments, the `hostname` field in the answerfile is combined with the machine's MAC address, so each system gets a unique hostname even though they share the same answerfile.
---
## Overlay Structure
```
setup/archiso/overlay/
├── airootfs/
│ ├── etc/motd # Welcome message
│ ├── root/
│ │ └── launch.sh # Installer entry point
│ └── usr/local/bin/
│ └── install-arch # User-facing CLI command
├── packages.extra # Additional live-system packages
└── profiledef.sh # M-Archy ISO profile definition
```
The `build.sh` script also adds at build time:
```
airootfs/root/installer/
├── arch-autoinstall.sh
└── archbaseos-guided-install.sh
```
---
## Writing the ISO to USB
```bash
# Find the USB drive
lsblk
# Write (replace /dev/sdX with your drive — ALL DATA WILL BE ERASED)
sudo dd if=~/m-archy-out/m-archy-*.iso of=/dev/sdX bs=4M status=progress oflag=sync
```
Or use `ventoy` / `balenaEtcher` as alternatives.