[HDFS-5338] Add a conf to disable hostname check in DN registration

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.3.0
• Component/s: namenode
• Hadoop Flags: Reviewed
• Assignee: Tsz-wo Sze
• Reporter: Tsz-wo Sze
• Created: 10/Oct/13 01:52
• Updated: 24/Feb/14 20:56
• Resolved: 15/Oct/13 18:26

Description

During DN registration, if the ip and the hostname in the DN InetAddress are the same (i.e. reverse name lookup falied; see the javadoc), the DN will be disallowed to register, where the DN InetAddress was obtained from the socket. It is a performance improvement added by HDFS-3990 to avoid unnecessary DNS resolutions.

We propose to add a conf property for disabling the check. Otherwise, clusters without reverse DNS lookup support does not work.

Issue Links

• is broken by: HDFS-3990 NN's health report has severe performance problems
• relates to: HDFS-4269 DatanodeManager#registerDatanode rejects all datanode registrations from localhost in single-node developer setup