[HADOOP-8156] Remove ability to specify a custom nameserver for an interface in DNS.java

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: conf
• Hadoop Flags: Incompatible change
• Assignee: Eli Collins
• Reporter: Eli Collins
• Created: 08/Mar/12 23:29
• Updated: 22/Jun/12 05:02

Description

A long time ago HADOOP-497 introduced the option to specify a specific nameserver to use when looking up the hostname of an interface specified in the config (eg by dfs.datanode.dns.interface). This feature is not in MR2, and I dont't think it makes sense for HDFS since HDFS stopped advertising DNs by hostname a long time ago (HADOOP-985). Also per HADOOP-8134 and HBASE-4109, I don't think this feature works, as it returns the PTR record verbatim instead of the hostname (eg PTR record may have a trailing ".", ".lan" etc that may not resolve).

How about we remove this feature from trunk and 23? We can deprecate in 1.0, though I doubt anyone is using it. This is an incompatible change. DNS is annotated LimitedPrivate and Unstable but HBase uses it so will file need to file a jira there (they use this via HBASE-1279 and HBASE-1279).

Issue Links

• is related to: HBASE-4109 Hostname returned via reverse dns lookup contains trailing period if configured interface is not "default"
• relates to: HBASE-5587 Remove dns.interface configuration options