feat: soft pod anti-affinity for broker, etcd, and proxy#153
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…— BUG-0012 Operator-managed broker and etcd StatefulSets shipped with no anti-affinity, so all replicas could schedule onto one node and a single node loss took out the whole quorum. Add a preferred (soft) podAntiAffinity over each StatefulSet's own pod labels keyed on kubernetes.io/hostname. Soft so the single-node KIND demo still schedules every replica; on a multi-node cluster the scheduler spreads them. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
…hook
PLAN-06 iter-7 E-14 / G-007. The chart-templated proxy is the only
multi-replica workload bp-001 controls through this chart (operator-
managed brokers + etcd are tracked in BUG-0012). Defaults match the
soft-anti-affinity shape we want everywhere:
* podAntiAffinity / preferredDuringSchedulingIgnoredDuringExecution,
weight 100, topologyKey kubernetes.io/hostname. Soft so single-
node KIND clusters still schedule both proxy replicas; flip to
requiredDuring in a multi-node production overlay.
* topologySpreadConstraints: [] by default; populate per-cluster
when multi-zone topology is available.
Templates extended:
* proxy-deployment.yaml: added topologySpreadConstraints hook
next to the existing affinity hook (both gated by `with`).
Chart bump 0.4.1 -> 0.4.2.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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What
Add soft (preferred) pod anti-affinity so replicas of the same component avoid co-locating on one node:
topologySpreadConstraintshook in valuesAll soft (
preferredDuringSchedulingIgnoredDuringExecution), so single-node clusters still schedule every replica; flip to required in multi-node production.Why
Without it the scheduler can place all replicas of a component on one node, defeating the replication. Soft anti-affinity is the standard HA default.
Test
go build ./pkg/operator/...green;helm templaterenders proxypodAntiAffinity.Part of a small series upstreaming deployment-hardening deltas we currently carry.