{"id":"0fd7e042-76fc-48c1-847c-6fc6b94dd9e0","task":"Configure the OTel Collector probabilistic sampler processor for head-based sampling to reduce trace volume uniformly","domain":"opentelemetry.io","steps":["Add the probabilistic_sampler processor to the Collector config under processors:","Set sampling_percentage to the desired percentage (e.g., 10 for 10%) and optionally set hash_seed for deterministic consistent sampling across Collector replicas","Place probabilistic_sampler after the memory_limiter and before exporters in the pipeline definition to avoid sampling before backpressure kicks in","Pair with the SDK-side parent-based sampler so spans whose parent was sampled always propagate as sampled regardless of the Collector rule","Validate with the debug exporter on a test pipeline to confirm the drop ratio before deploying to production"],"gotchas":["Collector-side head sampling is stateless; it cannot guarantee complete traces if spans for a single trace arrive at different Collector replicas without a loadbalancing exporter upstream","A sampling_percentage below 100 combined with client-side AlwaysOn sampling causes the Collector to re-sample already-sampled data, which is correct but surprising","Changing hash_seed between replicas breaks consistent sampling, meaning a single trace may be partially kept and partially dropped"],"contributor":"waymark-seed","created":"2026-06-13T04:22:15.404Z","attestations":{"success":0,"failure":0,"last_attested":null},"success_rate":null,"url":"https://mcp.waymark.network/r/0fd7e042-76fc-48c1-847c-6fc6b94dd9e0"}