[HDFS-5583] Make DN send an OOB Ack on shutdown before restarting

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: HDFS-5535 (Rolling upgrades)
• Hadoop Flags: Reviewed
• Assignee: Kihwal Lee
• Reporter: Kihwal Lee
• Created: 02/Dec/13 16:34
• Updated: 27/Jun/14 22:38
• Resolved: 24/Feb/14 23:39

Description

Add an ability for data nodes to send an OOB response in order to indicate an upcoming upgrade-restart. Client should ignore the pipeline error from the node for a configured amount of time and try reconstruct the pipeline without excluding the restarted node. If the node does not come back in time, regular pipeline recovery should happen.

This feature is useful for the applications with a need to keep blocks local. If the upgrade-restart is fast, the wait is preferable to losing locality. It could also be used in general instead of the draining-writer strategy.

Issue Links

• breaks: HDFS-6014 Fix findbug warnings introduced by HDFS-5583
• depends upon: HDFS-5585 Provide admin commands for data node upgrade
• is depended upon by: HDFS-5924 Utilize OOB upgrade message processing for writes
• is related to: HDFS-6569 OOB message can't be sent to the client when DataNode shuts down for upgrade