[HADOOP-8049] Add entry point/script to do preflight checking of script resolution

• Type: New Feature
• Status: Resolved
• Priority: Minor
• Resolution: Duplicate
• Affects Version/s: 1.0.0, 0.24.0
• Component/s: util
• Assignee: Unassigned
• Reporter: Steve Loughran
• Created: 09/Feb/12 17:33
• Updated: 02/May/13 02:29
• Resolved: 15/Oct/12 09:58

Description

The script supplied by the ops team could have many problems

1. not run
2. have the wrong permissions
3. fail to parse/resolve some or all hosts
4. not be the string set in the configuration file.

Diagnostics could be improved here with an entry point that

1. reads in the configuration file
2. instantiates whatever mapper is declared
3. attempts to resolve all hosts passed in as arguments, logging success and failures
4. prints out a topology map at the end
   A key goal would be to recognise and report a complete failure to report a mapping as per MAPREDUCE-50, so let people identify problems in their script before updating the cluster

Test plan
-Java entry point: invoke it with arguments, get the output as a string and scan.
-Shell script. Include whatever post-install script tests are being written.

Issue Links

• depends upon: HADOOP-8046 Revert StaticMapping semantics to the existing ones, add DNS mapping diagnostics in progress
• duplicates: HADOOP-8232 Provide a command line entry point to view/test topology options
• relates to: HADOOP-10867 NPE in heartbeat when the configured topology script doesn't exist