[HDFS-15290] NPE in HttpServer during NameNode startup

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.10.0, 2.7.8, 3.3.0
• Fix Version/s: 3.2.2, 2.10.1, 3.3.1, 3.4.0
• Component/s: namenode
• Target Version/s: 2.10.0
• Assignee: Simbarashe Dzinamarira
• Reporter: Konstantin Shvachko
• Created: 21/Apr/20 01:27
• Updated: 30/Aug/20 17:31
• Resolved: 30/Aug/20 17:31

Description

When NameNode starts it first starts HttpServer, then starts loading fsImage and edits. While loading the namesystem field in NameNode is null. I saw that a StandbyNode sends a checkpoint request, which fails with NPE because NNStorage is not instantiated yet.
We should check the NameNode startup status before accepting checkpoint requests.