Atlassian is replacing the internals of a large StatsD-based metrics platform with OpenTelemetry while keeping the interface used by application teams largely unchanged. The approach turns a company-wide instrumentation rewrite into a platform migration that can move one layer at a time.
In a CNCF engineering post, Atlassian says the existing gostatsd pipeline handled metrics from roughly 100,000 hosts across 14 regions with a 99.95% service-level objective. Its limitations were architectural: UDP-only input, no common path for traces or logs, and growing duplication of features already available in the OpenTelemetry Collector ecosystem.
Keep the contract, replace the engine
Applications previously sent StatsD packets to a familiar address. Atlassian preserved that contract while replacing the collection sidecar with a custom OpenTelemetry Collector distribution that accepts both StatsD and OTLP.
The migration is divided into collection, ingest, aggregation and forwarding. Each stage gets a purpose-built collector distribution so it can be changed without forcing all services to move at once.
Combining metrics with an existing tracing sidecar reduced average CPU use by 3.9% per service across Atlassian’s most expensive Micros services, which the company describes as roughly a 30% reduction in sidecar cost at fleet scale.
Better routing flattened hot shards
The old ingest layer routed traffic by service and environment. Because a small number of large services produced disproportionate volumes, some aggregation shards became overloaded while others sat idle.
OpenTelemetry’s load-balancing exporter let the team hash by individual time-series identity instead. That kept each series on one shard while spreading a large service across the pool, producing a more even CPU distribution and better off-peak scaling.
At the aggregation stage, Atlassian says the pipeline receives about 4.8 billion datapoints per minute and writes about 220 million after reducing redundant delta metrics. The company built and open-sourced a custom delta-aggregation processor. The new aggregation tier uses about half the CPU, according to the engineering report.
The migration is still in progress. Atlassian plans to move application instrumentation itself toward OpenTelemetry SDKs after the platform can accept both old and new inputs. Its broader lesson is operational: preserve the user-facing contract, roll through lower-risk environments first and profile components under real production load rather than trusting small benchmarks.
