[RATIS-993] Support pre vote

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.0.0
• Component/s: server
• Assignee: runzhiwang
• Reporter: runzhiwang
• Created: 02/Jul/20 12:35
• Updated: 27/Sep/23 09:09
• Resolved: 06/Jan/21 14:32

Description

For example, leader is s1, and s2, s3 are the followers. If there is something wrong with s3's network, and s3 lose connection with leader in a short time interval, s3 will trigger election. when s3's network recovery, leader will step down which is unnecessary. So I want to add pre vote before real vote.

1. if s3 want to request vote, it first send a pre vote request.
2. when s1 and s2 receive pre vote request of s3, they check their electionTimeout to decide whether should trigger leader election.
3. If s1 and s2 refuse to trigger a new leader election, s3 still keep as follower.

Issue Links

• is related to: RATIS-1273 Fix split brain by leader lease
• is related to: RATIS-1282 Refactor the code for preVote and vote in LeaderElection
• is related to: RATIS-1808 Rerun PreVote when Vote is timed out
• links to: GitHub Pull Request #161

Sub-Tasks

• Use a config to enable/disable pre vote: Resolved