felhom.eu/scripts/iso

Felhom bare-metal ISO pipeline (R-21 slice A + B)

Turns the official Proxmox VE ISO into a Felhom auto-install ISO whose first-boot chain, unattended, fetches and runs felhom-host-install.sh until the host is enrolled and a guest is provisioned. Boot the ISO on blank hardware → walk away → managed Felhom host.

Grounding: every install/first-boot/webhook mechanism used here is proven in documentation/audits/SPIKE-baremetal-iso-2026-07-16.md (S1–S8). This pipeline composes them; it does not modify felhom-host-install.sh (which it only invokes over the public distribution channel).

Scope: slice A = the pipeline + the in-ISO bootstrap, validated on nested VM 310. The physical N100 run is RUNBOOK B (separate, supervised). The customer-facing claim/pairing that removes the secret from the ISO is slice C (not built here).

Files

File	Role
Dockerfile.assistant	build host: Debian trixie + proxmox-auto-install-assistant (paired to the ISO's PVE generation by Debian codename) + xorriso + shellcheck
build-felhom-iso.sh	the pipeline: render answer, mint throwaway root hash, validate-answer output-parse gate, render stub, prepare-iso, optional --loader mkimage surgery, emit ISO + sha256 + manifest
mkimage-surgery.sh	slice-B loader surgery (runs in the container, post-prepare-iso): builds a monolithic grub-mkimage UEFI loader and swaps it into the ISO's EFI boot path (F1 firmware fix)
answer.toml.tmpl	Proxmox answer template (__FQDN__ / __ROOT_HASH__ / __ROOT_SSH_KEYS__ / __DISK_SETUP__ placeholders; [first-boot] from-iso/fully-up)
profiles/*.profile	disk-selection + fqdn fragments (sourceable, no secret)
stub-first-boot.sh	the ONE first-boot executable (skeleton; build injects the bootstrap script/unit/env as base64)
felhom-bootstrap.sh	per-attempt: fetch host-install from the public channel → run it with the retrieval passphrase → on rc 0 write done-flag + disable
felhom-bootstrap.service	retry-forever unit (Type=oneshot, Restart=on-failure, RestartSec=30, StartLimitIntervalSec=0)

Build

# 1. build the assistant image once (rebuild when the target PVE generation changes)
docker build -f scripts/iso/Dockerfile.assistant -t felhom-iso-assistant:trixie scripts/iso

# 2. build an ISO (on the build host; PVE ISO pre-downloaded + its official sha256)
scripts/iso/build-felhom-iso.sh \
  --pve-iso   /path/proxmox-ve_9.2-1.iso \
  --iso-sha256 4e88fe416df9b527624a175f24c9aa07c714d3332afb1ee3dbf3879573ef2c6c \
  --profile   scripts/iso/profiles/nested-vm.profile \
  --bootstrap-env /secure/bootstrap.env \
  --out       ~/felhom-iso/out

Output: felhom-pve-<pvever>-v<isover>-<profile>.iso + .sha256 + .manifest.txt.

The build gates the answer on validate-answer's OUTPUT TEXT, never $? — validate-answer returns exit 0 even on a broken file (spike S1 trap; also prepare-iso was observed to exit 0 on a bad answer). A broken answer aborts the build with the validator's message and produces no ISO. Note validate-answer is syntactic only: disk existence is a runtime property (a non-existent disk passes the build and fails-safe at install — spike S5c/S8b).

Profile format

A sourceable shell fragment:

FELHOM_FQDN="felhom-host.local"
FELHOM_DISK_SETUP='[disk-setup]
filesystem = "ext4"
disk-list = ["sda"]'
# optional emergency/validation key baked into root's authorized_keys (blank -> not baked):
# FELHOM_ROOT_SSH_KEY="ssh-ed25519 AAAA... ops@felhom"

FELHOM_DISK_SETUP is any valid Proxmox [disk-setup] block — a disk-list OR a udev filter.* glob. A filter matching nothing, or a non-existent disk, fails-safe: the installer aborts (exit 1, no disk touched) rather than installing on the wrong disk (spike S5c). Never commit a real key in FELHOM_ROOT_SSH_KEY unless it is meant to ship in every ISO built from that profile.

A profile may also set FELHOM_LOADER="shim"|"mkimage" (see below); --loader on the command line overrides it.

Loader modes (--loader shim|mkimage, slice B)

The UEFI boot loader is selectable. Default shim; a profile can pin FELHOM_LOADER; --loader wins over both.

• shim (default) — the stock output: the ISO's MS-signed shim → GRUB chain. Secure Boot keeps working on compliant firmware (no MOK, no keypress — spike S2b). Use this everywhere it boots.

• mkimage — replaces the ISO's UEFI boot path with a monolithic grub-mkimage loader built from the ISO's own GRUB modules. This is the fix for cheap AMI (AN3PLUS 0.01-class) mini-PC firmware that cannot UEFI-boot the ISO's stock GRUB from USB (relocation 0x0 is not implemented yet; SB-off and shim-bypass don't help) — the F1 finding of tests/VALIDATION-n100-baremetal-2026-07-16.md, worked around live during that run and now first-class. The recipe (module set from the ISO's grub.cfg, embedded search --fs-uuid → configfile the real menu) is reproduced from the run evidence, not re-derived.

  ⚠ mkimage is UNSIGNED → the target board MUST have Secure Boot OFF. With Secure Boot enforcing the firmware refuses the loader (Access Denied, no boot — proven, RUNBOOK-B leg 3). mkimage ISOs are named with a -mkimage suffix and the manifest's loader: line says so; never confuse them with a shim (SB-capable) build. shim mode's output is byte-for-byte the same as before this flag existed (the surgery is skipped entirely).

  The surgery runs after prepare-iso and touches only the EFI boot path — the answer file and the on-first-boot payload are provably byte-identical to the shim variant's (RUNBOOK-B leg 4).

bootstrap-env (SECRET-BEARING)

The --bootstrap-env file becomes the in-ISO /etc/felhom/bootstrap.env:

FELHOM_CUSTOMER_ID=<hub customer id>          # required
FELHOM_MODE=appliance                         # required (appliance|byo)
FELHOM_RETRIEVAL_PASSPHRASE=<customer passphrase>   # required — SECRET
# optional:
# FELHOM_HUB_URL=https://hub.felhom.eu
# FELHOM_INSTALL_URL=https://felhom.eu/scripts/felhom-host-install.sh
# FELHOM_EXTRA_ARGS="--cores 4 --memory 8192"   # profile-only flags, never secrets

Why the ISO is secret-bearing (§4.4 finding): the hub install-command's distribution channel is the public https://felhom.eu/scripts/felhom-host-install.sh — no token, no secret in the command. But felhom-host-install.sh requires the customer retrieval passphrase (normally a no-echo prompt) to fetch the config and enroll the host. An unattended install must supply it via --passphrase-file, so the ISO embeds it. Rules for a secret-bearing ISO:

• supervised / single-use only; never distributed; delete after the run.
• issue the passphrase with the shortest usable lifetime; rotate/retire after the install.
• the bootstrap shreds bootstrap.env on the box once host-install succeeds (reduces secret-at-rest).
• slice C removes this: the claim/pairing flow delivers the passphrase (or config) to the box after the customer claims it, so the distributed ISO carries no secret.

The first-boot chain

stub-first-boot.sh (exactly-once, [first-boot] from-iso/fully-up) is dumb: it lays down /usr/local/sbin/felhom-bootstrap.sh, the systemd unit, and /etc/felhom/bootstrap.env (0600), then enables + starts the unit. All fallible/network work lives in felhom-bootstrap.service, which retries forever until felhom-host-install.sh exits 0, then writes /etc/felhom/.bootstrap-done, disables itself, and scrubs the env. Retry-vs-resume: the first attempt is plain; any later attempt that finds /var/lib/felhom-install/state.json adds --resume (safe per host-install v1.11.3 — its producer steps re-run each pass).

N100 profile (for RUNBOOK B)

Use the committed profiles/n100.profile template (cheap-board, FELHOM_LOADER="mkimage"). A real single-disk mini-PC uses a unique-serial udev filter, not disk-list:

1. Boot once (or use a live env), harvest the target disk's udev id: udevadm info --query=property --name=/dev/sda | grep -E 'ID_SERIAL_SHORT|ID_MODEL|ID_WWN'.
2. In the profile, set filter.ID_SERIAL_SHORT = "<harvested>" + filter-match = "all". A match-nothing filter fails-safe (won't wipe the wrong disk).
3. Prior-LVM prerequisite: the auto-installer does not force-clear a pre-existing LVM PV signature — a disk with a previous Linux/Proxmox install aborts at "cannot init physical volume" (spike S2b). Wipe first: blkdiscard -f /dev/<disk> (or wipefs -a + zero the PV region).
4. Boot loader + Secure Boot (F1): cheap AMI (AN3PLUS-class) firmware can't boot the stock GRUB from USB, so profiles/n100.profile uses --loader mkimage. That loader is unsigned → set Secure Boot to OFF/Disabled in the BIOS before booting the stick (with SB enforcing the board refuses it: Access Denied, no boot). Firmware that boots the stock ISO fine needs no mkimage and keeps Secure Boot working (default shim, spike S2b). Optional pre-flight (operator, no risk): a n100-safety ISO — --loader mkimage + a match-nothing filter — boots the board, loads GRUB, and the installer aborts touching nothing (S5c). It confirms the loader + SB-off setting before the real install; its sha is recorded at build. Never boot the real install-armed ISO except in the supervised rehearsal.
5. BIOS "State After G3" → "Power On" (or "Last State") before final sign-off — so the mini-PC auto-powers-on after a mains loss (a managed appliance must come back without a physical press). Set it in the BIOS power/ACPI menu; it is board-specific and cannot be scripted (operator step).

Validation status (nested VM 310, 2026-07-16)

PASS: build gate + red-proof (C); disk-filter fail-safe through the pipeline (D); stub→unit→real public-channel fetch→correct host-install invocation→retry; 2.3 resume decision; exactly-once stub; no-network retry + auto-recovery (B). Operator-gated (not live-proven here): host-install rc-0 terminal success → hub-enrolled + guest-provisioned + done-flag + unit-disable — needs a properly created drill customer (the hub create-UI is password-gated and a live-DB insert is unsafe). Also out of scope: the physical N100 run (RUNBOOK B).