feat(k8s): scale core-api to 2 replicas with PDB and surge-only rollouts#208
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Implements action items 3 and 5 of docs/adr/0001-sse-multi-replica.md. Prereqs landed first: sse:ctl:resubscribe control channel (#206) and Redis-backed rate-limit counters (#207). With those in, no remaining core-api state assumes a single pod. - replicas: 2 with maxUnavailable: 0 / maxSurge: 1 so deploys never drop below capacity; SSE clients ride through on their 3s retry - PodDisruptionBudget (minAvailable: 1) so node drains and cluster upgrades cannot take the whole API down - cdc-runbook diagram now shows the per-replica Redis pub/sub fan-out and the resubscribe control channel Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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Summary
Action items 3 + 5 of ADR-0001 — the final step. Prereqs already merged:
sse:ctl:resubscribecontrol channel (#206) and Redis-backed rate-limit counters (#207). With those deployed, no remaining core-api state assumes a single pod.replicas: 2withmaxUnavailable: 0/maxSurge: 1— rollouts surge a new pod before killing an old one, so deploys stop being micro-outages; SSE clients ride through on their 3s retryminAvailable: 1) so node drains and cluster upgrades can't take the whole API downMerge order matters: merge only after #206 and #207 have deployed to the cluster (both are in main; confirm the core-api rollout finished).
Test plan
kubectl -n scrollr get pods -l app=core-apishows 2 Ready pods/healthnever 503s from the gateway (zero-drop rollout)🤖 Generated with Claude Code