[SLING-7830] Defined leader switch

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Discovery Oak 1.2.22
• Fix Version/s: Discovery Oak 1.2.28
• Component/s: Discovery
• Assignee: Stefan Egli
• Reporter: Carsten Ziegeler
• Created: 15/Aug/18 11:56
• Updated: 27/Sep/19 09:43
• Resolved: 28/Aug/18 09:48

Description

The current leader selection is based on startup time and sling id (mainly) and is stable across changed in the topology for as long as the leader is up and running.
However there are use cases like blue green deployment where new instances with a new version are started and taking over the functionality. However with the current discovery setup, the leader would still be one of the instances with the old version.
With a new deployed version, tasks currently bound to the leader should run on the new version.
Therefore the leader needs to switch and stay the leader (until it dies).

We probably need an additional criteria for the leader selection

/cc stefanegli

Issue Links

• links to: GitHub Pull Request #1