[HADOOP-59] support generic command-line options

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.2.0
• Fix Version/s: 0.4.0
• Component/s: conf
• Assignee: Hairong Kuang
• Reporter: Doug Cutting
• Created: 24/Feb/06 07:30
• Updated: 03/Jan/07 00:36
• Resolved: 27/Jun/06 04:11

Description

Hadoop commands should all support some common options. For example, it should be possible to specify the namenode, datanode, and, for that matter, any config option, in a generic way.

This could be implemented with code like:

public interface Tool extends Configurable {
void run(String[] args) throws Exception;
}

public class ToolBase implements Tool extends Configured {
public final void main(String[] args) throws Exception

{ Configuration conf = new Configuration(); ... parse config options from args into conf ... this.configure(conf); this.run(); }

}

public MyTool extends ExcecutableBase {
public static void main(String[] args) throws Exception

{ new MyTool().main(args); }

}

The general command line syntax could be:

bin/hadoop [generalOptions] command [commandOptions]

Where generalOptions are things that ToolBase handles, and only the commandOptions are passed to Tool.run(). The most important generalOption would be '-D', which would define name/value pairs that are set in the configuration. This alone would permit folks to set the namenode, datanode, etc.

Issue Links

• depends upon: HADOOP-319 FileSystem "close" does not remove the closed fs from the fs map
• is depended upon by: NUTCH-143 Improper error numbers returned on exit
• is related to: HADOOP-220 Add -dfs and -jt command-line parameters to specify namenode and jobtracker.