In October 2024, Leyang enhanced the apache/hadoop repository by implementing targeted observability improvements for HDFS block placement. Focusing on backend development and distributed systems, Leyang added a dedicated Java log entry to the Block Placement Policy, capturing cases where node selection is rejected due to upgrade-domain conflicts. This change improves diagnostics for administrators during upgrade activities, enabling faster troubleshooting and better upgrade readiness. The solution was carefully scoped to minimize performance impact, with logging introduced only in the relevant upgrade-domain path and accompanied by comprehensive tests. Leyang’s work demonstrates depth in logging, distributed systems, and backend engineering within a complex codebase.