If CloudTrail records "who did what (action)," AWS Config continuously tracks "what state is it in (state)." They don't compete; they complement. CloudTrail tells you "who changed S3 bucket policy," Config tells you "is that bucket public now, is encryption on." Today from the SOA operator's perspective, we cover Configuration Item structure, Rule evaluation trigger differences, Custom Rule Lambda implementation, Conformance Pack, Auto Remediation, and using Aggregator to assess company-wide compliance.
Config's basic data unit is Configuration Item. A new CI is created every time resource change is detected