questions about the configuration file

[Yunhong Gu1 <yg...@bert.cs.uic.edu>]

Hi,

I have some questions on the network settings.

What is the different between the following two entries?
The first one is obvious, but what does the second one mean? How is it 
related to DNS?

<property>
   <name>dfs.datanode.bindAddress</name>
   <value>0.0.0.0</value>
   <description>
     the address where the datanode will listen to.
   </description>
</property>

<property>
   <name>dfs.datanode.dns.interface</name>
   <value>default</value>
   <description>The name of the Network Interface from which a data node should
   report its IP address.
   </description>
</property>


For example, if my server has two IPs:

eth2	192.168.0.1
eth3	10.0.0.1
lo	127.0.0.1

I want to use 10.0.0.1. So I set the first entry as 10.0.0.1. How about 
the second one? eth3?

I use IP addresses and my server does not use domain name to talk to other 
servers (10.0.0.x).

Does the host name matter with regard to the above setting? Does 
/etc/hosts matter?

Does DNS matter if I dont use domain name at all? I asked this question 
because Hadoop always use host name in its report and I worry that it 
cannot locate the slave servers by the host name because no DNS is set.

Thanks
Yunhong