Comprehensive security update automation:
1. Debian OS (unattended-upgrades) — tightened to security-only:
- Removed general Debian updates (prevents feature/breaking changes)
- Only Debian-Security origins auto-installed
- Email admin on every upgrade via ops@performancewest.net
- Auto-reboot at 4 AM if kernel update requires it
- needrestart auto-restarts services after library updates
2. Docker CE — major version guard:
- Patch updates within pinned major version auto-applied
- Major version jumps held + admin alerted for manual review
- docker-ce, docker-ce-cli, containerd.io all version-guarded
3. Container base images — daily at 3:30 AM:
- Pulls latest base images for all docker-compose services
- Compares image digests — only rebuilds if changed
- Restarts only affected services (not full stack)
- Alerts admin on rebuild failures requiring manual intervention
- Covers both prod and dev compose projects
4. k3s — weekly Sunday at 3:45 AM:
- Patch updates within current minor auto-applied
- Minor/major upgrades alert admin for manual review
- Verifies node Ready status after update
- Alerts on failures with investigation instructions
5. Admin notifications via SMTP:
- [INFO] for successful patches
- [WARNING] for available major upgrades needing review
- [CRITICAL] for failures requiring immediate intervention
- Falls back to syslog if SMTP unavailable
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>