[KAFKA-16144] Controller leader checkQuorum timer should skip only 1 controller case

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 3.7.0
• Labels: newbie newbie++
• Assignee: Luke Chen
• Reporter: Luke Chen
• Created: 16/Jan/24 03:43
• Updated: 23/Jan/24 02:18
• Resolved: 23/Jan/24 02:18

Description

In KAFKA-15489, we fixed the potential "split brain" issue by adding the check quorum timer. This timer will be updated when the follower fetch request arrived. And it expires the timer when the there are no majority of voter followers fetch from leader, and resign the leadership.

But in KAFKA-15489, we forgot to consider the case where there's only 1 controller node. If there's only 1 controller node (and no broker node), there will be no fetch request arrived, so the timer will expire each time. However, if there's only 1 node, we don't have to care about the "check quorum" at all. We should skip the check for only 1 controller node case.

Currently, this issue will happen only when there's 1 controller node and no any broker node (i.e. no fetch request sent to the controller).

Issue Links

• is duplicated by: KAFKA-16163 Constant resignation/reelection of controller when starting a single node in combined mode
• is duplicated by: KAFKA-16170 Continuous never ending logs observed when running single node kafka in kraft mode with default KRaft properties in 3.7.0 RC2
• links to: GitHub Pull Request #15235