#!/usr/bin/env bash
# Rebuild a guest's cloud-init seed image and publish it into the libvirt pool.
# Run on the lab host.
#
#   ./rebuild-seed.sh 1
#
# The same content lives in three places: the source YAML, the ISO, and the
# uploaded pool volume. Editing the YAML alone changes nothing, which is why
# this is a script and not a set of remembered commands.
#
# A rebuilt seed only takes effect on a freshly created VM. cloud-init runs its
# per-instance modules once per instance-id, so an existing guest ignores it.
set -euo pipefail

N="${1:?usage: rebuild-seed.sh <1|2>}"
CLOUD_DIR="${CLOUD_DIR:-$HOME/workspace/cloud}"
POOL="${POOL:-default}"
export LIBVIRT_DEFAULT_URI="${LIBVIRT_DEFAULT_URI:-qemu:///system}"

cd "$CLOUD_DIR"
src="kc-lab-${N}.yaml"
iso="seed-kc-lab-${N}.iso"
meta="meta-kc-lab-${N}"

[ -f "$src" ] || { echo "missing $CLOUD_DIR/$src" >&2; exit 1; }

# A fresh instance-id makes cloud-init treat the guest as new and re-run the
# per-instance modules.
printf 'instance-id: kc-lab-%s-%s\nlocal-hostname: kc-lab-%s\n' \
  "$N" "$(date +%s)" "$N" > "$meta"

# NoCloud looks for a volume labelled cidata holding files named exactly
# user-data and meta-data. -graft-points renames them inside the image so no
# staging directory is needed.
xorrisofs -quiet -output "$iso" -volid CIDATA -joliet -rock -graft-points \
  "/user-data=${src}" "/meta-data=${meta}"

size="$(stat -c%s "$iso")"
virsh vol-delete --pool "$POOL" "$iso" >/dev/null 2>&1 || true
virsh vol-create-as "$POOL" "$iso" "$size" --format raw >/dev/null
virsh vol-upload --pool "$POOL" "$iso" "$iso"

echo "$iso published to pool '$POOL' ($size bytes)"
echo "attach it as a virtio disk, not a SATA cdrom:"
echo "  --disk vol=${POOL}/${iso},device=disk,bus=virtio,readonly=on"
echo "Debian genericcloud images carry no AHCI driver, so a SATA cdrom is invisible"
echo "to the guest and cloud-init fails with no error anywhere."