Apache Kudu is a distributed columnar storage system designed for fast analytics on fast data. It provides a horizontally scalable, fault-tolerant storage layer that integrates tightly with the Hadoop ecosystem (Spark, Impala, Hive, Flink). The architecture consists of master servers managing metadata and tablet servers storing data in columnar files (CFile) with Raft-based replication for consistency. The codebase includes production-grade C++ core, multi-language client libraries (Java, C++, Python, Spark), a comprehensive RPC framework, security features (Kerberos, TLS, Ranger), and extensive testing infrastructure. While primarily an application, it also contains benchmarking and experimental code (TPC-H, Jepsen, performance experiments) that give it a minor hybrid character. The repository is actively maintained with a large community and demonstrates strong engineering practices, though some vendored code and platform-specific workarounds indicate moderate technical drift.