Developed an observability enhancement for the apache/hadoop repository by introducing targeted logging to the HDFS block placement policy. The work focused on adding a dedicated log entry when a node is rejected due to upgrade-domain conflicts, improving diagnostic capabilities for administrators during upgrade operations. Using Java and leveraging backend development and distributed systems expertise, the implementation ensured minimal performance impact by scoping the logging specifically to the upgrade-domain decision path. Comprehensive tests were included to verify correct behavior. This feature enables faster troubleshooting and supports operational readiness by increasing visibility into upgrade-domain decisions within HDFS block placement workflows.