Answer: Cluster Event Log

The **Cluster Event Log**, found on the compute (cluster) details page, is the primary tool for reviewing lifecycle events. It records every autoscale resize event (both up and down) with a precise timestamp, the reason for the event, and the system component that triggered it. This allows a Data Engineer to correlate capacity changes with specific user activities or heavy query execution times. * **Workspace audit logs** track high-level administrative actions (e.g., notebook deletions, permission changes) but do not provide granular, per-cluster scaling logic. * **Driver and Executor log files** contain application-level `stdout` and `stderr` for debugging code performance or failures, rather than infrastructure scaling events. * **Ganglia / Metrics UI** provides a visual representation of CPU and memory usage, showing that capacity changed, but it does not provide the metadata explaining the 'why' or 'who' behind a resize trigger.

Author: LeetQuiz Editorial Team