[HDFS-14961] [SBN read] Prevent ZKFC changing Observer Namenode state

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.3.0
• Hadoop Flags: Reviewed
• Assignee: Ayush Saxena
• Reporter: Íñigo Goiri
• Created: 07/Nov/19 01:47
• Updated: 02/Nov/20 22:35
• Resolved: 28/Nov/19 13:09

Description

HDFS-14130 made ZKFC aware of the Observer Namenode and hence allows ZKFC running along with the observer NOde.
The Observer namenode isn't suppose to be part of ZKFC election process.
But if the Namenode was part of election, before turning into Observer by transitionToObserver Command. The ZKFC still sends instruction to the Namenode as a result of previous participation and sometimes tend to change the state of Observer to Standby.

This is also the reason for failure in TestDFSZKFailoverController.

TestDFSZKFailoverController has been consistently failing with a time out waiting in testManualFailoverWithDFSHAAdmin(). In particular waitForHAState(1, HAServiceState.OBSERVER);.

Issue Links

• is duplicated by: HDFS-15664 Prevent Observer NameNode from becoming StandBy NameNode
• is related to: HDFS-14130 Make ZKFC ObserverNode aware
• is related to: HDFS-15023 [SBN read] ZKFC should check the state before joining the election
• relates to: HDFS-14998 [SBN read] Update Observer Namenode doc for ZKFC after HDFS-14130