tree cc67aee4c3d5826097abe2da07ff153a7396f357
parent 29f2ef7cd9169ce8e0b474228c59a3a1da71e5c2
author mynameborat <bharath.kumarasubramanian@gmail.com> 1598495972 -0700
committer GitHub <noreply@github.com> 1598495972 -0700
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SAMZA-2439: Remove LocalityManager and container location information from JobModel (#1421)

Issues
Currently locality information is part of job model. Job model typically is immutable and fixed within the lifecycle of an application attempt. The locality information on the other hand is dynamic and changes in the event of container movements. Due to this difference, it makes it complicated to program, model or define semantics around these models when building features. Furthermore, by removing this dependency

- Enables us to move JobModel to public APIs and expose it in JobContext
- Enables us to cache and serve serialized JobModel from the AM servlet to reduce AM overhead (memory, open connections, num threads) during container startup, esp. for jobs with a large number of containers (See: #1241)
- Removes tech debt: models should be immutable, and should not update themselves.
- Removes tech debt: makes current container location a first class concept for container scheduling / placement , and for tools like dashboard, samza-rest, auto-scaling, diagnostics etc.

Changes
- Separated out locality information out of job model into LocalityModel
- Introduced an endpoint in AM to serve locality information
- Added Json MixIns for locality models (LocalityModel & ContainerLocality)
- Moved JobModel to samza-api and exposed through JobContext

API Changes:
- Introduced new models for locality.
- Previous job model endpoint will no longer serve locality information. i.e. tools using these will need to update to use the new endpoint.
- Expose JobModel via JobContext