The 2026-06-07 disk-full outage (flagship 100%, postgres crash-looping
on its pidfile, prod + staging down): cd-apps DOES prune images after
deploys, but it had been failing early all day (migration bug), so its
prune never ran — while ~10 staging/preview deploys kept pulling fresh
images with no prune of their own.
- cd-staging: prune superseded layers (until=1h guard against racing
in-flight pulls) after persistent staging and preview deploys.
- disk-maintenance.yml: NEW daily scheduled prune (04:30 UTC) that
also FAILS when the disk is still ≥85% after pruning — a redundant
alert channel for exactly the case where the Grafana disk alert
drowns in other noise, as it did during the incident.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
