[RATIS-1298] Support non-voting members (Listeners)

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Implemented
• Component/s: server
• Assignee: Yaolong Liu
• Reporter: Rui Wang
• Created: 27/Jan/21 18:37
• Updated: 02/Nov/23 04:48
• Resolved: 02/Nov/23 04:48

Description

It's time to add the non-voting member, or leaner that is proposed in Raft thesis 4.2.1 (you can find a copy at [1]).

The leaner is useful to maintain high availability when new servers join Raft ring (details at thesis 4.2.1). For Ozone SCM HA effort, we have also discussed the possibility to utilize leaner as the tool to replace SCM nodes online.

[1]: https://github.com/ongardie/dissertation

Issue Links

• links to: Design Doc

Sub-Tasks

• Support listener in RaftConfiguration: Resolved
• Support listeners in AdminApi, SetConfigurationRequest and proto.: Resolved
• Support Listener in RaftServerImpl: Resolved
• Support listener in setConfiguration: Resolved
• Support starting a server as a Listener: Resolved
• Can't use set configuration to add a new Listener correctly: Resolved
• Support listener in MiniRaftCluster: Resolved
• Add unit-test of listener related to setConfiguration and takeSnapshot: Resolved
• Add unit-test of listener related to leaderElection: Resolved
• Make listener reject leader election: Resolved