[RATIS-1001] add currentTerm to LeaderInfoProto for supporting SCM-HA.

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Component/s: server
• Assignee: Glen Geng
• Reporter: Glen Geng
• Due: 31/Jul/20
• Created: 14/Jul/20 07:51
• Updated: 02/Dec/20 08:32
• Resolved: 16/Jul/20 09:02

Description

 During SCM-HA, SCM not only needs to know whether it is a leader, but also needs to know which term it is in charge of.

 

Assume such a case: underlying raft node was leader on term 1, then step down as follower on term 2, then init election and become leader again on term 3. If term is not exposed together with leader information, SCM can not distinguish a leader of term 1 from that of term 3.

 

BTW the way, according to nanda's design, leader SCM need propagate its term to Datanode, RaftServerImpl::getRoleInfoProto() will be a good place to expose term from Ratis to SCM

 

Issue Links

• links to: GitHub Pull Request #151
• links to: GitHub Pull Request #312