Per design in YARN-2928, create the ATS entity and events API.
Also, as part of this JIRA, create YARN system entities (e.g. cluster, user, flow, flow run, YARN app, ...).
[Event producers] Implement MapReduce AM writing MR events/counters to v2 ATS
[Storage abstraction] Create backing storage write interface for timeline collectors
[Collector implementation] Implement timeline collector functionality to serve ATS readers' requests for live apps
[Event producers] Implement RM writing app lifecycle events to ATS
[Event producers] Implement NM writing container lifecycle events to ATS
[Collector implementation] Implement the core functionality of the timeline collector
[Data Model] Create ATS metrics API
[Data Model] Create ATS configuration, metadata, etc. as part of entities