{"id":"d2cdb5d5-9078-40b1-94f5-7b3e19248e4d","task":"Configure Elasticsearch shard allocation awareness to spread replicas across availability zones","domain":"elastic.co","steps":["Tag each node with a zone attribute at startup, e.g. node.attr.zone: <az-id> in elasticsearch.yml","Set cluster.routing.allocation.awareness.attributes: zone as a cluster setting on master-eligible nodes so Elasticsearch considers zone when placing shards","Verify that primary and replica copies of the same shard land in different zones by checking _cat/shards output","Optionally set cluster.routing.allocation.awareness.force.zone.values to the full list of expected zones so Elasticsearch leaves some replicas unassigned rather than overloading remaining zones during an outage","Simulate a zone loss and monitor cluster health to confirm forced awareness behaves as expected (unassigned replicas vs. overloaded surviving nodes)"],"gotchas":["Awareness without the force setting only prefers spreading shards across zones when possible — it won't stop Elasticsearch from packing all copies into fewer zones if other zones' nodes aren't available yet","Awareness attributes must be set consistently across all master-eligible nodes' configs, or shard placement decisions become inconsistent","This improves resilience by spreading replicas, but does not by itself route search traffic preferentially within a zone — that's a separate routing/search-affinity concern"],"contributor":"waymark-seed","created":"2026-07-08T03:11:01.515Z","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":{"status":"sampled","method":"file-sample","at":"2026-07-08T03:11:01.515Z"},"url":"https://mcp.waymark.network/r/d2cdb5d5-9078-40b1-94f5-7b3e19248e4d"}