Just for clarity, DNS as a service is NOT Required. Name resolution is. I use /etc/hosts files to identify all nodes in my clusters.
One of the reasons for using Names over IP's is ease of use. I would much rather use a hostname in my XML to identify NN, JT, etc. vs. some random string of numbers. On Mon, Jul 29, 2013 at 10:40 AM, Greg Bledsoe <[email protected]> wrote: > I can third this concern. What purpose does this complexity increasing > requirement serve? Why not remove it? > > Greg Bledsoe > > From: 武泽胜 <[email protected]> > Reply-To: "[email protected]" <[email protected]> > Date: Mon, 29 Jul 2013 08:21:51 -0500 > To: "[email protected]" <[email protected]> > Subject: Re: Why Hadoop force using DNS? > > I have the same confusion, anyone who can reply to this will be very > appreciated. > > From: Elazar Leibovich <[email protected]> > Reply-To: "[email protected]" <[email protected]> > Date: Thursday, July 25, 2013 3:51 AM > To: user <[email protected]> > Subject: Why Hadoop force using DNS? > > Looking at Hadoop source you can see that Hadoop relies on the fact each > node has resolvable name. > > For example, Hadoop 2 namenode reverse look the up of each node that > connects to it. Also, there's no way way to tell a database to advertise an > UP as it's address. Setting datanode.network.interface to, say, eth1, would > cause Hadoop to reverse lookup UPs on eth1 and advertise the result. > > Why is that? Using plain IPs is simple to set up, and I can't see a reason > not to support them? >
