[HADOOP-8629] Add option for TableMapping to reload mapping file on match failure

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Won't Fix
• Component/s: util
• Assignee: Unassigned
• Reporter: Steve Loughran
• Created: 28/Jul/12 00:18
• Updated: 21/Jan/21 13:35
• Resolved: 21/Jan/21 13:35

Description

As commented in HADOOP-7030, the table mapping topology mapper handles new node addition worse than the script mapping, because the table mapping is frozen for the life of the service.

I propose adding an option (true by default?) for the class to look at the timestamp of the mapping file, and reload it on a change -if a hostname lookup failed.

Issue Links

• depends upon: HADOOP-8928 Add ability to reset topologies on master nodes
• relates to: HADOOP-7030 Add TableMapping topology implementation to read host to rack mapping from a file