[OpenAFS] Re: AFSDB dns lookup

Pedro Perez pperez@opensourcetechnologies.net
Mon, 03 Apr 2006 13:48:59 -0400

Jeffrey Hutzelman wrote:

> On Monday, April 03, 2006 01:22:16 PM -0400 Pedro Perez 
> <pperez@opensourcetechnologies.net> wrote:
>> IF /etc/nsswitch.conf could contain a line like this:
>> afs: dns files
>> OR
>> afs: files dns
>> things would work just like DNS. Could this be a possible solution?
> Not really.  It turns out that the innards of the name service switch 
> are completely different from one operating system to the next, and 
> not very extensible in this direction.  Doing what you describe would 
> require extending the 'files' and 'dns' nss backends to understand the 
> "afs" database, which can't be done without replacing the modules the 
> OS vendor provides (if they're even provided as modules, which is not 
> required).
Ah, I understand. Thanks for the information. I learned something from it.

> Also, a "solution" to what?

I think I choosed the wrong word there. Sorry. "Alternative" would have 
been a much better word.

But, what I was trying to say was that with such an alternative (which 
you have already explained been hard to implement), AFS could be 
configured to ignore CellServDB in favor of AFSDB records (quote ". . . 
you can't make AFS ignore the CellServDB in favor of looking up AFSDB 

> We could probably make it possible to tell the cache manager to use 
> DNS first, but what would be the point?  If you want to rely primarily 
> on the DNS for locating AFS servers, then your CellServDB should be 
> mostly empty, containing only entries for cells where the nameservers 
> are unresponsive, or hand out incorrect data, or where you otherwise 
> want to override the data handed out in the DNS.

> -- Jeffrey T. Hutzelman (N3NHS) <jhutz+@cmu.edu>
>   Sr. Research Systems Programmer
>   School of Computer Science - Research Computing Facility
>   Carnegie Mellon University - Pittsburgh, PA
Thanks for your time and explanation,
Pedro Perez