[RATIS-1912] Fix infinity election when perform membership change.

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.0
• Component/s: election
• Assignee: Jinglun
• Reporter: Jinglun
• Created: 19/Oct/23 07:53
• Updated: 06/Nov/23 02:38
• Resolved: 03/Nov/23 20:46

Description

Starting new peers with empty conf when membership changes can cause infinity election.

Supposing we want to replace 2 peers from a 3 peers cluster. Normally we start the 2 new peers with empty conf. This can cause an infinity election and make the cluster unavailable forever.
 
I will upload a patch to describe the case. And I will upload a document to describe the current dilemma when performing membership changes.

TestMembership simulates the 'replacing 2 peers from a 3 peers cluster' issue. It ends with an infinity leader election.  (https://github.com/apache/ratis/pull/943/files)

Issue Links

• is related to: RATIS-1930 Add a conf for enable/disable majority-add.
• relates to: RATIS-1911 Create a simple example to demonstrate how to perform ratis cluster membership changes.
• links to: GitHub Pull Request #954
• links to: Patch fix the bug.
• links to: Patch showing the bug.