Phase 6 of v0.3. The update agent now refuses to apply artifacts whose
channel doesn't match local policy, whose architecture differs from the
running host, or whose min_compatible_version is above the current
version. It also refuses to apply outside a configured maintenance window
unless --force is given.
New package update/pkg/config:
- config.Load parses /etc/kubesolo/update.conf (key=value, # comments,
unknown keys ignored). Missing file is fine — fresh systems before
cloud-init has run.
- ParseWindow handles "HH:MM-HH:MM" plus the wrapping midnight case
(e.g. "23:00-01:00"). Empty input -> AlwaysOpen (no constraint).
Degenerate zero-length windows never match.
- CompareVersions does a simple 3-component semver compare with the 'v'
prefix optional and pre-release suffix ignored.
- 14 unit tests total.
update/pkg/image/image.UpdateMetadata gains three optional fields:
- channel ("stable", "beta", ...)
- min_compatible_version (refuse upgrade if current < this)
- architecture ("amd64", "arm64", ...)
update/cmd/opts.go reads update.conf and merges it into opts; explicit
--server / --channel / --pubkey / --maintenance-window CLI flags override
the file. New --force, --conf, --channel, --maintenance-window flags.
Precedence: CLI > config file > package defaults.
update/cmd/apply.go gains four gates in order:
1. Maintenance window — checked locally before any HTTP work; skipped
with --force.
2. Channel — refused if metadata.channel doesn't match opts.Channel.
3. Architecture — refused if metadata.architecture != runtime.GOARCH.
4. Min compatible version — refused if FromVersion < min_compatible.
All gate failures transition state to Failed with a clear LastError.
cloud-init gains a top-level updates: block (Server, Channel,
MaintenanceWindow, PubKey). cloud-init.ApplyUpdates writes
/etc/kubesolo/update.conf from those fields on first boot. Empty block
leaves any existing file alone (so hand-edited update.conf survives a
reboot without cloud-init re-applying). 4 new tests cover empty / all /
partial / parent-dir-creation cases. full-config.yaml example updated.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Implement atomic OS updates via A/B partition scheme with automatic
rollback. GRUB bootloader manages slot selection with a 3-attempt
boot counter that auto-rolls back on repeated health check failures.
GRUB boot config:
- A/B slot selection with boot_counter/boot_success env vars
- Automatic rollback when counter reaches 0 (3 failed boots)
- Debug, emergency shell, and manual slot-switch menu entries
Disk image (refactored):
- 4-partition GPT layout: EFI + System A + System B + Data
- GRUB EFI/BIOS installation with graceful fallbacks
- Both system partitions populated during image creation
Update agent (Go, zero external deps):
- pkg/grubenv: read/write GRUB env vars (grub-editenv + manual fallback)
- pkg/partition: find/mount/write system partitions by label
- pkg/image: HTTP download with SHA256 verification
- pkg/health: post-boot checks (containerd, API server, node Ready)
- 6 CLI commands: check, apply, activate, rollback, healthcheck, status
- 37 unit tests across all 4 packages
Deployment:
- K8s CronJob for automatic update checks (every 6 hours)
- ConfigMap for update server URL
- Health check Job for post-boot verification
Build pipeline:
- build-update-agent.sh compiles static Linux binary (~5.9 MB)
- inject-kubesolo.sh includes update agent in initramfs
- Makefile: build-update-agent, test-update-agent, test-update targets
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
