[HDFS-7542] Add an option to DFSAdmin -safemode wait to ignore connection failures

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Later
• Affects Version/s: 2.6.0
• Component/s: tools
• Labels: BB2015-05-TBR
• Target Version/s: 2.8.0
• Assignee: Stephen Chu
• Reporter: Stephen Chu
• Created: 17/Dec/14 22:04
• Updated: 02/Jun/15 18:02
• Resolved: 02/Jun/15 18:02

Description

Currently, the dfsadmin -safemode wait command aborts when connection to the NN fails (network glitch, ConnectException when NN is unreachable, EOFException if network link shut down).

In certain situations, users have asked for an option to make the command resilient to connection failures. This is useful so that the admin can initiate the wait command despite the NN not being fully up or survive intermittent network issues. With this option, the admin can rely on the wait command continuing to poll instead of aborting.