[REEF-1648] Allow transition from ALLOCATED to RUNNING in EvaluatorState

• Type: Sub-task
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Fix Version/s: 0.16
• Component/s: REEF-Common
• Assignee: Mariia Mykhailova
• Reporter: Mariia Mykhailova
• Created: 22/Oct/16 00:32
• Updated: 01/Nov/16 23:01
• Resolved: 26/Oct/16 19:12

Description

In REEF-62 we introduced state transition checks, which were refactored several times. However, these checks don't cover all allowed scenarios. In driver restart scenario restarted driver initially has all evaluators in `ALLOCATED` state, and when evaluators from first run reconnect to driver, they report they are in `RUNNING` state, so driver refuses to recognize them.

We need to allow this transition for the restarted driver to recognize reconnecting evaluators.