release 1.1.2v1.1.2

Also records the host config the chain depends on. The schedule and the
storage layout existed only on the VM, so a rebuilt host would have lost
both, and the README's inline copy of the schedule had already drifted
from what actually runs. crontab.example is byte-identical to the
deployed crontab; fstab.example carries the two-disk layout and the
dockerd mount-namespace trap that makes moving the registry store
non-obvious.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

10 files changed, 182 insertions, 29 deletions

diff --git a/ChangeLog.md b/ChangeLog.md
index cb817ed..1cdbe3d 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -4,6 +4,40 @@ All notable changes to this project are documented here. Format follows
 [Keep a Changelog](https://keepachangelog.com/), versioning is
 [SemVer](https://semver.org/).
 
+## [1.1.2] - 2026-09-22
+
+Disk exhaustion on the build host, from three directions. The nightly
+`-current` chain had been failing for ten nights with "no space left on
+device", and because each stage is gated on the previous one's digest, the
+later stages skipped silently: the `-current` tags sat six days stale while
+`15.0` rebuilt fine and nothing reported an error.
+
+### Added
+- `image-builder/registry-gc.sh`: reclaim unreferenced blobs from the
+  registry store, which never shrinks on its own. Stops the registry for a
+  stable blob graph, refuses to run against OCI-index manifests (distribution
+  2.8.x deletes their children), and verifies a tag still resolves afterwards.
+- `image-builder/crontab.example` and `image-builder/fstab.example`: reference
+  copies of the host schedule and storage layout, recorded so a rebuilt VM is
+  reproducible. They previously existed only on the VM.
+
+### Changed
+- Each build now prunes its own superseded image right after pushing, instead
+  of leaving it resident until a daily prune. A replaced `sbo-full:current` is
+  ~33G of dead weight that the next variant had to build around.
+- The registry store belongs on a different disk from the docker volume. It
+  grows with every push while the build needs a large transient peak at a
+  fixed hour; sharing one volume pits a slow leak against a hard failure.
+  `fstab.example` documents the layout, including the dockerd mount-namespace
+  trap when moving an existing store.
+- The README points at `crontab.example` rather than repeating the schedule,
+  which is how the inline copy had gone stale.
+
+### Fixed
+- `bootstrap.sh`, `build-full-image.sh` and `build-sbo-testbuild.sh` abort
+  early when the docker daemon is unreachable, instead of failing deeper in
+  with a less obvious error.
+
 ## [1.1.1] - 2026-07-16
 
 ### Fixed
diff --git a/image-builder/README b/image-builder/README
index 86c463f..5910497 100644
--- a/image-builder/README
+++ b/image-builder/README
@@ -13,10 +13,19 @@ Three scripts, chained (see docs/specs/2026-07-13-image-builder-design.md):
 Plus one maintenance script (not part of the chain):
   registry-gc.sh         reclaim unreferenced blobs from the registry store
 
+And two reference copies of the host config the chain depends on. Nothing
+reads them; they are here so a rebuilt VM is reproducible:
+  crontab.example        the nightly schedule, as deployed
+  fstab.example          the two-disk storage layout, as deployed
+
 All settings live in ./config.
 
-VM setup (docker.noland.dnx, Slackware x86_64, 4 vCPU / 4 GB / 80 GB)
---------------------------------------------------------------------
+VM setup (docker.noland.dnx, Slackware x86_64, 4 vCPU / 4 GB)
+-------------------------------------------------------------
+Two disks, and which is which matters: a system disk (80 GB, also holding the
+registry store) and a separate docker volume (160 GB) for images and build
+scratch. See fstab.example.
+
 1. Install docker; enable the daemon.
 
 2. NFS-mount the two NAS trees read-only, named to match:
@@ -25,10 +34,17 @@ VM setup (docker.noland.dnx, Slackware x86_64, 4 vCPU / 4 GB / 80 GB)
    Each is a full mirror (PACKAGES.TXT, ChangeLog.txt, slackware64/, patches/,
    extra/). Root must be able to read them (bootstrap runs installpkg as root).
 
-3. Run a LAN registry (storage on the same disk as docker, bind-mounted):
+3. Run a LAN registry. Put its storage on a DIFFERENT disk from docker's:
      docker run -d --restart=always -p 5000:5000 \
        -v /opt/sbo-testbuild/registry:/var/lib/registry --name registry registry:2
 
+   The bind target belongs on the system disk, not the docker volume. The
+   registry grows with every push and never shrinks on its own, while the
+   build needs a large transient peak at a fixed hour; sharing one volume
+   pits a slow leak against a hard failure, and the build loses. See
+   fstab.example for the layout and the dockerd-namespace trap if you move
+   an existing store.
+
 4. Mark the registry insecure (plain HTTP) on the VM AND every pulling client
    (this dev box, the buildsystem VM). In /etc/docker/daemon.json:
      { "insecure-registries": ["docker.noland.dnx:5000"] }
@@ -44,26 +60,16 @@ VM setup (docker.noland.dnx, Slackware x86_64, 4 vCPU / 4 GB / 80 GB)
    full-image on the base-image digest, build-sbo-testbuild on the full-image
    digest + tools .txz hash), so an unchanged night is a cheap no-op. -current
    moves daily and rebuilds most nights; 15.0 is frozen stable and rebuilds only
-   on a real repo update. Deployed schedule on docker.noland.dnx:
-      # -current (ready ~04:35)
-      0  3 * * *  /path/to/sbo-dockerbuild/image-builder/bootstrap.sh           --version current >> /var/log/sbo-testbuild.log 2>&1
-     20  3 * * *  /path/to/sbo-dockerbuild/image-builder/build-full-image.sh    --version current >> /var/log/sbo-testbuild.log 2>&1
-     30  4 * * *  /path/to/sbo-dockerbuild/image-builder/build-sbo-testbuild.sh --version current >> /var/log/sbo-testbuild.log 2>&1
-      # 15.0 (ready ~06:35)
-      0  5 * * *  /path/to/sbo-dockerbuild/image-builder/bootstrap.sh           --version 15.0 >> /var/log/sbo-testbuild.log 2>&1
-     20  5 * * *  /path/to/sbo-dockerbuild/image-builder/build-full-image.sh    --version 15.0 >> /var/log/sbo-testbuild.log 2>&1
-      30 6 * * *  /path/to/sbo-dockerbuild/image-builder/build-sbo-testbuild.sh --version 15.0 >> /var/log/sbo-testbuild.log 2>&1
-
-   Post-build cleanup, after the chain (which ends ~06:30) and before the 15:00
-   cache prune:
-      # daily: drop dangling images left behind when a tag moves to a new build
-      0  7 * * *  docker image prune -f >> /var/log/sbo-testbuild.log 2>&1
-      # weekly (Sunday): reclaim unreferenced blobs from the registry store
-      0  8 * * 0  /path/to/sbo-dockerbuild/image-builder/registry-gc.sh >> /var/log/sbo-testbuild.log 2>&1
-
-   The registry never reclaims blobs on its own, so without the weekly GC its
-   storage grows until the disk fills and the nightly builds fail with
-   "no space left on device" (see the section below).
+   on a real repo update.
+
+   The schedule lives in crontab.example, which is a copy of what the VM runs:
+     crontab crontab.example        # or paste it into `crontab -e`
+
+   Install it rather than retyping it. The timings are load-bearing, not
+   cosmetic: reclaim runs at 02:50, immediately before the 03:00 chain, so the
+   headroom exists when the build needs it. An earlier schedule pruned in the
+   afternoon instead and the -current build failed ten nights running with
+   "no space left on device". The file explains each window.
 
 7. Ensure docker.noland.dnx resolves on the LAN (static IP or DNS).
 
diff --git a/image-builder/bootstrap.sh b/image-builder/bootstrap.sh
index e632e7a..7bf87ac 100755
--- a/image-builder/bootstrap.sh
+++ b/image-builder/bootstrap.sh
@@ -14,7 +14,7 @@
 # bootstrap.sh — build the sbo-base:{ver} image FROM scratch from NAS trees.
 # Run as root (installpkg). Adapted from forge slackware/docker-images.
 set -euo pipefail
-PROJECT_VERSION="1.1.1"   # bump via sed across all scripts; see CLAUDE.md Releases
+PROJECT_VERSION="1.1.2"   # bump via sed across all scripts; see CLAUDE.md Releases
 HERE="$(cd "$(dirname "$0")" && pwd)"
 source "${HERE}/config"
 LOG_TAG=bootstrap
diff --git a/image-builder/build-full-image.sh b/image-builder/build-full-image.sh
index 6ca0288..47e034b 100755
--- a/image-builder/build-full-image.sh
+++ b/image-builder/build-full-image.sh
@@ -14,7 +14,7 @@
 # build-full-image.sh — sbo-full:{ver} FROM sbo-base:{ver}, all series.
 # Adapted from forge slackware/docker-images. No root needed.
 set -euo pipefail
-PROJECT_VERSION="1.1.1"   # bump via sed across all scripts; see CLAUDE.md Releases
+PROJECT_VERSION="1.1.2"   # bump via sed across all scripts; see CLAUDE.md Releases
 HERE="$(cd "$(dirname "$0")" && pwd)"
 source "${HERE}/config"
 LOG_TAG=full
diff --git a/image-builder/build-sbo-testbuild.sh b/image-builder/build-sbo-testbuild.sh
index d40ccb1..2bb8487 100755
--- a/image-builder/build-sbo-testbuild.sh
+++ b/image-builder/build-sbo-testbuild.sh
@@ -15,7 +15,7 @@
 # Adds sbopkg + sbo-maintainer-tools from prebuilt .txz in PKGDIR.
 # Rebuilds when the full image OR the .txz set changes.
 set -euo pipefail
-PROJECT_VERSION="1.1.1"   # bump via sed across all scripts; see CLAUDE.md Releases
+PROJECT_VERSION="1.1.2"   # bump via sed across all scripts; see CLAUDE.md Releases
 HERE="$(cd "$(dirname "$0")" && pwd)"
 source "${HERE}/config"
 LOG_TAG=testbuild
diff --git a/image-builder/crontab.example b/image-builder/crontab.example
new file mode 100644
index 0000000..174ace0
--- /dev/null
+++ b/image-builder/crontab.example
@@ -0,0 +1,68 @@
+# sbo-testbuild image chain, root's crontab on the docker host.
+#
+# Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+# GPLv2 only; see LICENSE.
+#
+# Reference copy of what the VM actually runs. Nothing reads this file: install
+# it with `crontab -` (or paste into `crontab -e`) and keep the two in step.
+# It is recorded here because the schedule is as much a part of the build
+# system as the scripts, and it used to live only on the VM, where a rebuilt
+# host would have lost it.
+#
+# Timings are not arbitrary. The chain is gated stage to stage, so each stage
+# must finish before the next starts, and every reclaim must land outside a
+# build window or it strips the working set mid-export.
+#
+#   02:50  reclaim    dangling images, then build cache to a 5G floor
+#   03:00  -current   bootstrap -> full -> testbuild
+#   05:00  15.0       bootstrap -> full -> testbuild
+#   07:00  reclaim    dangling images (catches both variants)
+#   08:00  registry   blob GC, Sundays only
+#
+# Repos sync at 01:00/02:00, so the chain starts after that and the images are
+# ready by 09:00.
+
+# ---------------------------------------------------------------------------
+# Pre-build reclaim
+# ---------------------------------------------------------------------------
+# Exporting the -current full image needs roughly its own size (~33G) in
+# transient space on top of what is already resident. An afternoon cache prune
+# with a 20G floor left the volume short by 03:20, and build-full-image.sh
+# failed ten nights running (2026-09-13 to 09-22) with "no space left on
+# device", always in the same export phase. build-sbo-testbuild.sh then saw an
+# unchanged parent and skipped silently, so the -current tags sat six days
+# stale while 15.0 rebuilt fine.
+#
+# Reclaiming just before the build, not hours after it, is what makes the
+# headroom exist when it is needed. Images first (debris from a previous
+# failure), then the cache down to a 5G floor.
+50 2 * * *   docker image prune -f >> /var/log/sbo-testbuild.log 2>&1
+55 2 * * *   docker builder prune -f --reserved-space 5g >> /var/log/sbo-testbuild.log 2>&1
+
+# ---------------------------------------------------------------------------
+# Build chain
+# ---------------------------------------------------------------------------
+# No --force: each script self-gates (bootstrap=ChangeLog hash, full=base
+# digest, testbuild=full digest + .txz hash), so an unchanged night is a cheap
+# no-op that exits in seconds.
+#
+# -current (moves daily):
+0  3 * * * /opt/sbo-testbuild/image-builder/bootstrap.sh           --version current >> /var/log/sbo-testbuild.log 2>&1
+20 3 * * * /opt/sbo-testbuild/image-builder/build-full-image.sh    --version current >> /var/log/sbo-testbuild.log 2>&1
+30 4 * * * /opt/sbo-testbuild/image-builder/build-sbo-testbuild.sh --version current >> /var/log/sbo-testbuild.log 2>&1
+# 15.0 (frozen stable; rebuilds only on a real repo update):
+0  5 * * * /opt/sbo-testbuild/image-builder/bootstrap.sh           --version 15.0 >> /var/log/sbo-testbuild.log 2>&1
+20 5 * * * /opt/sbo-testbuild/image-builder/build-full-image.sh    --version 15.0 >> /var/log/sbo-testbuild.log 2>&1
+30 6 * * * /opt/sbo-testbuild/image-builder/build-sbo-testbuild.sh --version 15.0 >> /var/log/sbo-testbuild.log 2>&1
+
+# ---------------------------------------------------------------------------
+# Post-build cleanup
+# ---------------------------------------------------------------------------
+# Since 1.1.2 each build prunes its own superseded image right after pushing,
+# so this is a backstop for anything those missed (a failed run, a manual
+# build). Cheap when there is nothing to do.
+0  7 * * *   docker image prune -f >> /var/log/sbo-testbuild.log 2>&1
+# The registry never reclaims on its own: every push adds blobs and nothing
+# removes them, so its store grows until the disk fills. Weekly is enough.
+# registry-gc.sh has its own safety gates; see the script.
+0  8 * * 0   /opt/sbo-testbuild/image-builder/registry-gc.sh >> /var/log/sbo-testbuild.log 2>&1
diff --git a/image-builder/fstab.example b/image-builder/fstab.example
new file mode 100644
index 0000000..79c9473
--- /dev/null
+++ b/image-builder/fstab.example
@@ -0,0 +1,45 @@
+# sbo-testbuild storage layout, /etc/fstab on the docker host.
+#
+# Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+# GPLv2 only; see LICENSE.
+#
+# Reference copy of the two entries this build system depends on. Nothing
+# reads this file; it is recorded so the layout survives a lost VM, because
+# where these live is not a detail. Getting it wrong is what broke the
+# nightly builds for ten days.
+#
+# The UUID below is this host's; use your own (`blkid /dev/sdb1`).
+
+# ---------------------------------------------------------------------------
+# Docker data: its own disk
+# ---------------------------------------------------------------------------
+# Build scratch space wants room to breathe. Exporting the -current full image
+# writes roughly its own size (~33G) transiently, on top of the images already
+# resident, so this volume is sized for the peak and not the steady state.
+# Everything on it is reproducible from the mirror, so it is excluded from
+# vzdump.
+UUID=0e5d008d-0ee0-41bc-9222-aedba1e088d0  /var/lib/docker  ext4  defaults  0  2
+
+# ---------------------------------------------------------------------------
+# Registry store: NOT on the docker disk
+# ---------------------------------------------------------------------------
+# The registry's blob store used to be a bind mount from the docker disk
+# (/var/lib/docker/registry-data). That put ~25G of permanently-resident data
+# on the same volume as the transient build peak, and the two competed: the
+# registry grows with every push, the build needs headroom at 03:20, and the
+# build lost. Moved to the system disk on 2026-09-22, which had 49G idle.
+#
+# Keep them separate. The registry is small, static and I/O-light; the build
+# disk is large, churning and latency-insensitive. Sharing one volume couples
+# a slow leak to a hard failure.
+#
+# If this host's backups cover the system disk, exclude /opt/registry-data:
+# the contents are reproducible by re-pushing the images.
+#
+# Moving it is not just an fstab edit. dockerd caches the mount in its own
+# namespace, so after remounting you must restart the daemon and recreate the
+# registry container, or pushes keep silently landing on the old disk. Verify
+# with:  grep ' /var/lib/registry ' /proc/$(docker inspect registry \
+#            --format '{{.State.Pid}}')/mountinfo
+# and check the device is the system disk, not the docker one.
+/opt/registry-data  /opt/sbo-testbuild/registry  none  bind  0  0
diff --git a/image-builder/registry-gc.sh b/image-builder/registry-gc.sh
index fab37bb..ef7a6ab 100644
--- a/image-builder/registry-gc.sh
+++ b/image-builder/registry-gc.sh
@@ -26,7 +26,7 @@
 # Intended as a weekly cron job, after the build chain and before the daily
 # cache prune. See README.
 set -euo pipefail
-PROJECT_VERSION="1.1.1"   # bump via sed across all scripts; see CLAUDE.md Releases
+PROJECT_VERSION="1.1.2"   # bump via sed across all scripts; see CLAUDE.md Releases
 HERE="$(cd "$(dirname "$0")" && pwd)"
 source "${HERE}/config"
 LOG_TAG=registry-gc
diff --git a/install.sh b/install.sh
index 0e703ec..b028e9d 100755
--- a/install.sh
+++ b/install.sh
@@ -22,7 +22,7 @@
 #   ./install.sh --uninstall  remove it
 
 set -euo pipefail
-PROJECT_VERSION="1.1.1"   # bump via sed across all scripts; see CLAUDE.md Releases
+PROJECT_VERSION="1.1.2"   # bump via sed across all scripts; see CLAUDE.md Releases
 HERE="$(cd "$(dirname "$0")" && pwd)"
 BINDIR="${BINDIR:-$HOME/bin}"
 PROG=test-build
diff --git a/test-build b/test-build
index 0db4aab..6899c05 100755
--- a/test-build
+++ b/test-build
@@ -23,7 +23,7 @@
 #
 # No em dashes in prose by author convention.
 
-PROJECT_VERSION="1.1.1"   # bump via sed across all scripts; see CLAUDE.md Releases
+PROJECT_VERSION="1.1.2"   # bump via sed across all scripts; see CLAUDE.md Releases
 
 # =============================================================================
 # CONFIG (do not edit here; real values live in the external config file)