Round Robin

Bill Larson wllarso at
Tue Nov 7 14:39:32 UTC 2006

On Nov 7, 2006, at 7:22 AM, Andy Shellam (Mailing Lists) wrote:

> In a short answer... No.
> DNS is only for translating a host-name into an IP address.
> It can return an IP address as a round-robin, regardless of whether  
> the
> server on that address is up, down, unavailable, non-existent.
> What you're asking for in essence is clustering.
> You'll be needing something else in your software like Heartbeat/ 
> Nagios
> to monitor nodes status and take action based on when a node goes down
> to take it out of the cluster.

There is a DNS "solution" available for this situation.  Take a look  
at "lbnamed", a "load balanced" DNS server.  It is NOT BIND, written  
in Perl, and is fairly old.  I'm sure that there should be security  
issues involved with trying to use this.

If your DNS server provides dynamic DNS capabilities, you could use  
some external script to run "nsupdate" to remove and add your servers  
to DNS as needed.

There are other, non-DNS, load balancing systems that may be much  
better solutions.  These operate by manipulating the network routing  
of a single address.  If you are really serious about this need, then  
this type of solution would be a much better solution, but costly.

But, as Andy said, the short answer for a DNS solution is "no".  DNS  
round robin won't provide a solution.

Bill Larson

> Andy.
> Fabio Silva wrote:
>> Hi all, i have a question about round robin, if a node goes down, the
>> DNS will send the packets to that node or DNS can understand that,
>> that node goes down??
>> Is there any other solution to do load balance like round robin?
>> Regards,
>> !DSPAM:37,4550955240419416277106!

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