[HDFS-14660] [SBN Read] ObserverNameNode should throw StandbyException for requests not from ObserverProxyProvider

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.10.0, 3.3.0, 3.1.4, 3.2.2
• Hadoop Flags: Reviewed
• Assignee: Chao Sun
• Reporter: Chao Sun
• Created: 18/Jul/19 05:30
• Updated: 03/Oct/19 23:54
• Resolved: 28/Jul/19 03:45

Description

In a HDFS HA cluster with consistent reads enabled (HDFS-12943), clients could be using either ObserverReadProxyProvider, ConfiguredProxyProvider, or something else. Since observer is just a special type of SBN and we allow transitions between them, a client NOT using ObserverReadProxyProvider will need to have dfs.ha.namenodes.<nameservice> include all NameNodes in the cluster, and therefore, it may send request to a observer node.

For this case, we should check whether the stateId in the incoming RPC header is set or not, and throw an StandbyException when it is not. 

Issue Links

• duplicates: HDFS-14636 SBN : If you configure the default proxy provider still read Request going to Observer namenode only.