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installer-iso: persist auto-install logs to the staging disk

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darman
2026-07-24 19:43:43 +02:00
parent 2543a1246b
commit ff92e24ff7
2 changed files with 108 additions and 34 deletions
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flake.nix
+56 -1
View File
@@ -291,6 +291,48 @@
exit 0
fi
# Persist this whole run to a file that OUTLIVES the install.
# The systemd journal is on the installer's tmpfs and dies with
# the reboot, and by the time anything interesting fails disko
# has already wiped the OS disk — so a failed attempt used to
# leave nothing to debug. local_install_prepare_and_reboot()
# (scripts/deploy) passes the STAGING partition's PARTUUID as
# homelab.logpart=; that partition holds the iso and is on a
# different disk from the one disko wipes, so it survives. The
# actual install runs inside do_install() below so one tee at
# the end captures all of it. Every step here is best-effort:
# logging must never be the thing that breaks an install.
logfile=""
logpart=$(grep -o 'homelab\.logpart=[^ ]*' /proc/cmdline | cut -d= -f2 || true)
if [ -n "$logpart" ]; then
dev="/dev/disk/by-partuuid/$logpart"
logdir=""
mkdir -p /run/homelab-log
if mount -o rw "$dev" /run/homelab-log 2>/dev/null; then
logdir=/run/homelab-log
elif where=$(findmnt -fno TARGET "$dev" 2>/dev/null) && [ -n "$where" ]; then
# stage-1's findiso already holds this partition mounted
# (that is how it reached the iso) — write into the existing
# mount rather than trying to stack a second one on it.
mount -o remount,rw "$where" 2>/dev/null || true
logdir="$where"
fi
if [ -n "$logdir" ]; then
# Next to the iso: findiso= is its path on this partition.
iso=$(grep -o 'findiso=[^ ]*' /proc/cmdline | cut -d= -f2 || true)
dest="$logdir/$(dirname "$iso" 2>/dev/null || echo /)"
if mkdir -p "$dest" 2>/dev/null; then
logfile="$dest/homelab-install-$cfg.log"
else
logfile="$logdir/homelab-install-$cfg.log"
fi
echo "logging this install to $logfile (on the staging disk — survives the wipe)"
else
echo "warning: could not mount PARTUUID=$logpart to log to — continuing without a persistent log" >&2
fi
fi
do_install() {
# The host key scripts/deploy seeds /etc/ssh with (so sops can
# decrypt on boot #1) cannot live in this ISO: it is built from
# a PUBLIC repo and the private keys are deliberately off-repo.
@@ -331,7 +373,20 @@
echo "auto-installing $cfg (homelab.install= on the kernel cmdline)"
cd /root/homelab
exec ./scripts/deploy install "$cfg" localhost --yes
./scripts/deploy install "$cfg" localhost --yes
}
# tee, not exec: we need the exit status back to sync the log
# to the platter before the box possibly drops to a shell.
if [ -n "$logfile" ]; then
{ echo "=== homelab auto-install: $cfg ($(date -u 2>/dev/null || true)) ==="; do_install; } 2>&1 | tee -a "$logfile"
status=''${PIPESTATUS[0]}
else
do_install
status=$?
fi
sync 2>/dev/null || true
exit "$status"
'';
};
})
scripts/deploy
+19
View File
@@ -342,6 +342,17 @@ local_install_prepare_and_reboot() {
[ "$stage_fstype" != btrfs ] \
|| die "$stagedir is btrfs: findiso= mounts the volume's top level, so a path inside a subvolume never resolves. Stage on a non-btrfs partition (ext4/vfat/ntfs)."
# PARTUUID of the staging partition. Handed to the installer as
# homelab.logpart= so it can mount this partition rw and persist its whole
# run — disko + nixos-install output included — to a file next to the iso.
# This partition is on a DIFFERENT disk from the one disko wipes (guarded
# above), so unlike $boot it SURVIVES the install: a failed attempt otherwise
# leaves nothing to debug, its journal having died on tmpfs at the reboot.
# Best-effort — an LVM/mdraid stage_src has no PARTUUID, in which case logging
# is simply skipped rather than blocking the install.
local stage_partuuid
stage_partuuid="$(lsblk -no PARTUUID "$stage_src" 2>/dev/null | head -1 | tr -d ' ' || true)"
# Last chance to back out. This is the most destructive command in the
# script — it reboots the machine you are typing at and the wipe that
# follows is unattended — so it confirms just like `flash` and `kexec-local`
@@ -354,6 +365,11 @@ local_install_prepare_and_reboot() {
echo " -> $osdisk_real ** WIPED, unattended, after the reboot **"
# Unquoted on purpose: collapses the one-per-line list onto one line.
echo " staging: $stagedir (on $(echo $stage_disks))"
if [ -n "$stage_partuuid" ]; then
echo " logs: $stagedir/homelab-install-$config.log (on the staging disk — survives the wipe)"
else
echo " logs: (none — $stagedir has no PARTUUID; installer output won't survive the wipe)"
fi
echo " one-shot: $boot_mode"
read -rp ">> type 'yes' to build the installer, reboot into it and wipe $osdisk_real: " ok
[ "$ok" = yes ] || die "aborted"
@@ -426,6 +442,9 @@ local_install_prepare_and_reboot() {
local cmdline volumeID
volumeID="$(nix eval --raw .#nixosConfigurations.installer-iso.config.isoImage.volumeID)"
cmdline="init=$toplevel/init nohibernate root=LABEL=$volumeID boot.shell_on_fail loglevel=4 lsm=landlock,yama,bpf findiso=$iso_relpath homelab.install=$config homelab.keypart=$boot_partuuid"
# Only when the staging partition has a PARTUUID (see stage_partuuid). Points
# the installer's homelab-auto-install.service at the surviving disk to log to.
[ -n "$stage_partuuid" ] && cmdline="$cmdline homelab.logpart=$stage_partuuid"
case "$boot_mode" in
systemd-boot)