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  1. Hadoop Common
  2. HADOOP-785

Divide the server and client configurations


    • Type: Improvement
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 0.9.0
    • Fix Version/s: 0.15.0
    • Component/s: conf
    • Labels:


      The configuration system is easy to misconfigure and I think we need to strongly divide the server from client configs.

      An example of the problem was a configuration where the task tracker has a hadoop-site.xml that set mapred.reduce.tasks to 1. Therefore, the job tracker had the right number of reduces, but the map task thought there was a single reduce. This lead to a hard to find diagnose failure.

      Therefore, I propose separating out the configuration types as:

      class Configuration;
      // reads site-default.xml, hadoop-default.xml

      class ServerConf extends Configuration;
      // reads hadoop-server.xml, $super

      class DfsServerConf extends ServerConf;
      // reads dfs-server.xml, $super

      class MapRedServerConf extends ServerConf;
      // reads mapred-server.xml, $super

      class ClientConf extends Configuration;
      // reads hadoop-client.xml, $super

      class JobConf extends ClientConf;
      // reads job.xml, $super

      Note in particular, that nothing corresponds to hadoop-site.xml, which overrides both client and server configs. Furthermore, the properties from the *-default.xml files should never be saved into the job.xml.


        1. HADOOP-785_4.patch
          19 kB
          Doug Cutting
        2. HADOOP-785_3_20070908.patch
          16 kB
          Arun C Murthy
        3. HADOOP-785_2_20070906.patch
          17 kB
          Arun C Murthy
        4. HADOOP-785_1_20070903.patch
          9 kB
          Arun C Murthy

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              • Assignee:
                acmurthy Arun C Murthy
                owen.omalley Owen O'Malley
              • Votes:
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                • Created: