* fix(relay): let a host leave a dead reserve cell without an operator fence
A host whose reserve home cell died got 503 relay_home_cell_unavailable until the
cell came back: the database path demands a committed fence for every capped cell.
On its own /v1/assign, a host now moves off a reserve cell (Postgres records it as
reserve) when the cell's heartbeat is stale and this director's seat-feed polls have
gone unanswered for 45 s, unless more than a third of the polled cells look the same.
Sweeps, migration pins and capped db cells keep the fence.
* fix(relay): guard the dead-cell verdict by region and sample size, and floor the move on the map
- No verdict when half or more of the dead cell's own region fails with it (a cross-region
partition), more than a third of the fleet does, or fewer than 6 cells are polled. A withheld
region or fleet verdict logs orca_relay_dead_cell_verdict_withheld, which alerts.
- The move needs the step-5 plan's epoch floor, so it mints above every seat the map knows;
without the plan the fence is kept. A test revives the old cell's seat above the row and checks
that the ledger never writes the row back.
- The move's log line carries the fleet and region counts.
* fix(relay): count only feed cells and young streaks in the dead-cell guards; gate the alert
- Denominators hold only cells that served this director a feed page and have capacity: legacy
rows answering 404 no longer fill the 6-cell sample or dilute the fleet and region ratios.
- A peer counts as failing for the guards on any current streak (a failure in the last 5 s), so a
staggered partition cannot let its first cell cross 45 s while its neighbours read healthy.
- Every withheld verdict is logged, sample included (a cell missing from the feed cells is one).
- Tests: ready=0 and enabled=0 with failing polls keep the fence (drain then death is fenced).
- The withheld metric and alert are gated by relay_dead_cell_verdict_alert (default false, on in
staging); the alert docs now describe poll failures, not heartbeats.
* fix(relay): always sample the dead-cell candidate, so a restarted director can still judge it
A director that restarted after a reserve cell died never received a feed page from it, so the
cell was never in the sample and its verdict stayed withheld as 'sample'. The candidate now always
counts when it has capacity (the store asks only about a cell Postgres records as reserve, and only
feed images run reserve); peers still count only once they have served a feed. Tests: a restart
during a lone outage decides, a partition begun before the restart withholds by region, and the
capacity filter. The Terraform comments now say to apply the metric first and the policy minutes later.
Jinwoo Hong
735e6d6c5d