Observatory: a reference implementation for production observability.
Observatory is an open-source observability system implemented as a single statically-linked binary. The system ingests metrics, structured logs, and distributed traces, persists them to an append-only columnar store, and exposes a query layer over the resulting Parquet shards. This document is the authoritative reference for the public preview release.
Cite as: Patil A., Reyes D., Yates M. Observatory Reference (v0.4.2), April 2026.
Specifications
| Release | v0.4.2 · public preview, 2026-04-12 |
|---|---|
| License | Apache License 2.0 |
| Architecture | Single-binary ingest, append-only columnar store, query layer over Parquet shards |
| Source | Apache 2.0 source distribution |
| Install | Single statically-linked binary, ~38 MiB |
| Runtime | x86_64 Linux, ARM64 Linux, macOS (Apple Silicon) |
| Storage | Local disk; S3-compatible object store optional |
| Telemetry | None. The binary makes no outbound calls. |
System overview
Observatory is composed of four cooperating components, each addressable as a subcommand of a single binary: the ingest service, the columnar store, the query layer, and the compactor. The four-component design reflects established practice in time-series data systems1; the consolidation into one binary is a deliberate ergonomic choice rather than an architectural innovation.
The ingest service accepts OpenTelemetry-compliant payloads over gRPC and HTTP. Incoming series are batched, labeled, and committed to local disk in immutable columnar segments. The compactor merges segments according to a tiered retention policy. The query layer exposes a SQL-flavored surface over the resulting columnar store, with histogram and percentile aggregations executed at the storage layer to avoid materializing intermediate rows.
No component requires coordination with an external service. In particular, Observatory does not transmit telemetry to its maintainers, does not check for updates, and does not require a license server. Operators who require coordinated cluster deployment may consult §4 of this document.
Installation
Operators may install Observatory by retrieving the statically-linked binary appropriate to their platform from the project source distribution and placing it on the system path. The binary is reproducible from source under the conditions documented in the project README. No additional runtime is required.
The configuration surface is a single TOML document; an empty configuration is a valid configuration and yields a local-disk single-tenant deployment suitable for evaluation. Production deployments are expected to specify storage targets, retention policies, and authentication settings as detailed in §5.
# Verify the binary
observatory --version
# observatory 0.4.2 (linux/amd64)
# Run with default (local disk, in-memory ingest)
observatory serve
# Run with a configuration file
observatory serve --config /etc/observatory/config.toml
Changelog excerpt
The following entries are reproduced from the project's authoritative CHANGELOG.md. Versions follow Semantic Versioning. Breaking changes are flagged in line. The full history is available with the source distribution.
- v0.4.22026-04-12
- Query planner: pushdown of histogram aggregations into the columnar layer.
- Storage: switch default Parquet compression to Zstandard at level 3.
- CLI: ‘observatory query’ now accepts ‘--explain’ for plan inspection.
- v0.4.12026-03-29
- Ingest: improved batching for high-cardinality label sets.
- Bugfix: incorrect rounding in 99.9th percentile aggregation under low-sample windows.
- v0.4.02026-03-04
- Distributed traces graduate from beta. Wire format frozen at v1.
- Compactor: per-tenant disk quota enforcement.
- Breaking: removal of legacy ‘obs-ingest’ binary in favor of unified ‘observatory’ entrypoint.
Notes
- The four-component decomposition is consistent with prior art in time-series systems, including Prometheus, VictoriaMetrics, and Mimir. Observatory's contribution is operational rather than architectural.
- The Apache 2.0 license includes an explicit patent grant. Operators redistributing Observatory should consult the
NOTICEfile alongside the source distribution. - This document is the public preview reference. The 1.0 reference will be issued when the wire format and on-disk format are both frozen.