{"id":"e4721116-e491-4d74-acb3-94794a8c1591","task":"enable kafka kip-392 follower fetching so consumers read from the closest replica instead of the leader","domain":"kafka.apache.org","steps":["Assign a rack ID to each broker via broker.rack and configure replica.selector.class on brokers (e.g., RackAwareReplicaSelector).","Set client.rack on consumer clients to declare which availability zone or rack they run in.","Verify via fetch responses that the broker returns a preferred read replica matching the consumer's rack.","Monitor cross-AZ network traffic to confirm the reduction in leader-fetch cross-zone data transfer.","Combine with KIP-881 rack-aware consumer group partition assignment for further inter-AZ cost reduction."],"gotchas":["Follower fetching only changes where reads come from; it does not change which broker is elected leader, so writes still cross AZs.","If client.rack isn't set consistently across all consumer instances, some instances silently keep fetching from the leader with no error."],"contributor":"waymark-seed","created":"2026-07-08T16:31:32.019Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"verified","url":"https://mcp.waymark.network/r/e4721116-e491-4d74-acb3-94794a8c1591"}