FerroDruid Container - Rust-native Apache-Druid-compatible OLAP

FerroDruid is a Rust-native, Apache-Druid-spec-compatible real-time OLAP database. It speaks the Druid REST API, native query JSON, and Druid SQL, and it reads Apache Druid segment v9 binary files (read compatibility verified against segments written by Druid 31.0.2 and 35.0.1, on local disk) - without a JVM, without ZooKeeper, and without a six-process control plane. A classic Apache Druid cluster needs six or more JVM processes plus ZooKeeper plus an external metadata database and 16 GB or more of RAM before it serves a query. FerroDruid's single-binary container replaces all of that with one process that starts in under a second on under 200 MB of RAM, so it runs cleanly on Amazon EKS and on serverless container compute (ECS/Fargate) where a classic Druid cluster cannot. What it does today (v1.2.0): it serves all eight Druid native query types; it runs Druid SQL (SELECT, WHERE, GROUP BY, HAVING, ORDER BY, LIMIT, 30+ functions, EXPLAIN PLAN FOR, an MSQ task endpoint; about 95 percent core SQL parity); it exposes 40+ Druid-compatible REST endpoints; it reads Apache Druid segment v9 - verified against segments written by Druid 31.0.2 and 35.0.1 - and writes segments in its own native format (the single-binary path uses SQLite metadata plus local-filesystem deep storage); it ingests from Kafka and Kinesis supervisors and via native batch; and it enforces Basic authentication (Argon2id) with role-based access control on by default and TLS via rustls. The admin account is created on first boot with a random per-instance password and the operator is required to change it on first login before any endpoint serves traffic. Engineering posture is verifiable: every crate uses #![forbid(unsafe_code)], clippy is clean at -D warnings, a CycloneDX SBOM and 18 fuzz targets run in CI, and images are cosign-signed. Live wire deep-match is clean against Apache Druid 31.0.2, 32.0.1, 33.0.0, 34.0.0, 35.0.1 and 36.0.0: on each version, 42 of 48 deep-compared queries match byte-for-byte with 0 mismatches (Sections 1 through 4 are 30 of 30 deep on every version), plus 5 of 5 with an Apache Superset connector. Druid 30.0.1 is the one partial version at 24 of 48, and every one of those diffs is Druid 30's own upstream behaviour of returning an empty result for SQL window functions (even with windowing enabled), not a FerroDruid defect. New in v1.2.0: SQL UNION ALL with Druid-compatible positional column mapping; a null-generation load path so NULL-typed columns round-trip faithfully; fail-closed Historical segment routing with exact O(1) cache-limit accounting; and a verified read of a real Apache Druid v9 segment round-tripped through real AWS S3 deep storage. The Helm chart deploys the supported single-binary shape and fails closed on multi-node / external-metadata / external-deep-storage values. The container performs an AWS Marketplace RegisterUsage entitlement check at startup and serves only if entitled. FerroDruid is now source-available under the Business Source License 1.1 (github.com/abyo-software/ferrodruid), converting to Apache-2.0 four years after each release; this listing sells a hardened, scanned, supported distribution. Commercial support is provided exclusively through AWS Marketplace (Standard support included with every paid subscription; Business and Enterprise tiers via AWS Marketplace private offers).