[TAJO-1143] TajoMaster, TajoWorker, and TajoClient should have diagnosis phase at startup

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.10.0
• Component/s: Java Client, QueryMaster, TajoMaster
• Assignee: Jihun Kang
• Reporter: Hyunsik Choi
• Created: 28/Oct/14 05:10
• Updated: 10/Dec/14 20:18
• Resolved: 10/Dec/14 19:52

Description

I propose that all cluster components (TajoMaster, TajoWorker, and TajoClient) in a Tajo cluster should have a diagnosis phase to eliminate or detect invalid situations prior to runtime query errors.

For example, your query can cause some runtime exception due to wrong config after a query takes 2 hours. This situation is definitely not acceptable in production.

I think that the diagnosis phase should check all configs, connectivities among cluster components, and status of workers.

In detail, we need a diagnosis executor, extensible diagnosis rule interface, and its rules. Also, one of diagnosis rules would be TAJO-1114.