Buckets could not choose which RGW placement target (and thus durability
profile) backs them, so all data landed on the cluster default. The estate's
radosgw exposes two targets - default-placement (3x replicated) and ec (4+1
erasure-coded) - and archival workloads want ec.
- Validate spec.placementTarget: a DNS-ish pattern, 63-char cap, and a CEL
self==oldSelf immutability rule (RGW fixes placement at bucket creation and
cannot move a bucket between targets); make spec.zonegroup immutable too.
- Thread the target into the S3 CreateBucket LocationConstraint via the existing
helper; an empty zonegroup yields ":<target>", selecting the local zonegroup
so callers need not name the zonegroup api-name.
- Read the live placement_rule and zonegroup back from the Admin Ops bucket
stats and surface them: status.placementTarget plus a Placement print column.
- Guard the controller: if a live bucket's placement differs from spec, set an
Error phase with a PlacementImmutable reason instead of deleting/recreating.
- Cover locationConstraint construction, placement readback (httptest), and the
placementConflict guard with tests; document targets and immutability in the
README and add config/samples/06-bucket-ec.yaml.
Claude-Session: https://claude.ai/code/session_015ur3i7D2azsMAWTSVABApv
