Dynamic DNS (address takeover-type-things)

[Medi Montaseri]

You can use lbnamed (load balancing named). That will be your Dynamic DNS.

However the problem with DNS approach is the amount of time it takes to
update cache servers. Unless you are talking about a local LAN where
all clients are always going to a DNS for the A records.

Note that you still have to detect a departure and a merger and deal
with it.

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Medi Montaseri                               medi@CyberShell.com
Unix Distributed Systems Engineer            HTTP://www.CyberShell.com
CyberShell Engineering
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On Mon, 19 Oct 1998 alanr@bell-labs.com wrote:

> I sent this more than 12 hours ago, and didn't see the return mail, so
> I'm sending it out again.  Sorry if you've seen it twice.  You can read
> about Dynamic DNS at:
> 		http://davidsimmons.com/tips/081797/
> -------------------------------------------------------------------------------
> Another thing I assume we would eventually like to do is to perform
> Dyanmic DNS
> reconfigurations on the basis of node availability.
> 
> Let me elaborate:
> In DNS one can have a round-robin scheme so that when a user requests a
> particular
> machine (like www.netscape.com), that it will be redirected to one of a
> set of
> machines in a round-robin fashion.  In Dynamic DNS, one can dynamically
> change the
> mapping of machine names to IP addresses.  Ultimately, if we add a
> machine to or
> remove a machine from a cluster served by this kind of DNS addressing,
> we would
> want to be able to update the DNS round-robin list as well.  For these
> kinds of
> applications, this would be much better than simply doing IP address
> takeover,
> since the load will remain balanced in this case.
> 
> For example, if I have three machines in a cluster, and one goes away,
> IP (or MAC)
> address takeover would give ALL the new load to one of the machines,
> making it
> twice as busy as the other.
> 
> DNS round-robin updates would allow the machines to share the load
> equally.
> I'm not 100% sure which particular DNS servers will allow you to change
> the
> configurations of round-robin groups.  If none do, then it certainly is
> a desirable
> feature.
> 
> Thoughts?
> 
> Does someone with more knowledge about Dynamic DNS want to comment?
> 
>         -- Alan Robertson
>            alanr@bell-labs.com
>