${user.name}, ${user.host}?

[sejong king <se...@yahoo.com>]

Hello,

In hadoop-site.xml, hadoop.tmp.dir uses ${user.name} to retrieve the username for its directory.  Is there a similar way to retrieve the name of the host that this particular datanode is starting up on? (in order to create unique directory names for each node.  something along the lines of: user.host, user.local.name, machine.name, etc...)

Thanks!
-Sej



      

Re: ${user.name}, ${user.host}?

[Doug Cutting <cu...@apache.org>]

Variables in configuration files may be Java system properties or other 
configuration parameters.  The list of pre-defined Java system 
properties is at:

http://java.sun.com/javase/6/docs/api/java/lang/System.html#getProperties()

Unfortunately the host name is not in that list.  You could define it by 
adding something like the following to conf/hadoop-env.sh:

HADOOP_DATANODE_OPTS="-Dhost.name=`hostname`"

Doug

sejong king wrote:
> Hello,
> 
> In hadoop-site.xml, hadoop.tmp.dir uses ${user.name} to retrieve the username for its directory.  Is there a similar way to retrieve the name of the host that this particular datanode is starting up on? (in order to create unique directory names for each node.  something along the lines of: user.host, user.local.name, machine.name, etc...)
> 
> Thanks!
> -Sej
> 
> 
> 
>