CoreDNS refused to load the new Corefile with `serve_stale 3600s 86400s`:
plugin/cache: invalid value for serve_stale refresh mode: 86400s
serve_stale takes one DURATION and an optional refresh_mode keyword
("immediate" or "verify"), not two durations. Simplified to
`serve_stale 86400s` (serve cached entries for up to 24h when upstream
is unreachable). The new CoreDNS pods were CrashLoopBackOff; the two
old pods kept serving traffic so there was no outage, but the partial
apply left the cluster wedged with the bad ConfigMap.
Also collapses the inline viktorbarzin.lan cache block.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
af6574a006