I'm not sure if this is the intended behavior, but it sounds like this JIRA
will change it. I found out the hard way that running
hadoop jar myMapReduceJob.jar
runs the M/R job with the current hadoop configuration. However running
hadoop -jar myMarReduceJob.jar
runs the M/R job with a different configuration, something that appears to be
stand alone mode. It drove me nuts for a few days before I realized that
sometimes I was typing the dash and sometimes not.
Dave
-----Original Message-----
From: Brock Noland (JIRA) [mailto:j...@apache.org]
Sent: Monday, May 23, 2011 9:23 PM
To: common-dev@hadoop.apache.org
Subject: [jira] [Created] (HADOOP-7325) hadoop command - do not accept class
names starting with a hyphen
hadoop command - do not accept class names starting with a hyphen
-----------------------------------------------------------------
Key: HADOOP-7325
URL: https://issues.apache.org/jira/browse/HADOOP-7325
Project: Hadoop Common
Issue Type: Improvement
Components: scripts
Reporter: Brock Noland
Priority: Minor
Attachments: hadoop-illegal-class-name-0.patch
If this is committed I will look at patches for hdfs and mapred.
When teaching a good portion of the students in every single class execute:
{code}
$ hadoop -fs ls /
{code}
The -fs is passed directly to the JVM and the JVM fails to start:
{code}
$ ./bin/hadoop -fs ls /
Unrecognized option: -fs
Could not create the Java virtual machine.
{code}
Which is confusing and typically requires explanation. The attached patch
improves that behavior:
{code}
$ ./bin/hadoop -fs ls /
Error: No command named `-fs' was found. Perhaps you meant `hadoop fs'
{code}
The only risk I can see is if someone is abusing the implementation of hadoop
command doing something like so:
{code}
$ ./bin/hadoop -Xmx1g org.apache.hadoop.util.RunJar
RunJar jarFile [mainClass] args...
{code}
The hadoop command does not appear to advertise allowing JVM options before the
classname.
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