C/C++ version Load balancer DNS

[Bryan Irvine]

<snip>

> Using DNS, I want to do load balancing of client requests among my
> available servers dynamically.
> In realtime requirements, any/many servers among the configured me be
> down or overloaded.
>
> I want to have control over distribution of load to these servers. I
> want to have a common FQDN to the clients and they know only FQDN. I
> would like to have 10/20 servers handling the client requests. When
> ever a server goes down, all the requests (thousands) it was handling,
> should come to remaining available servers quickly (assume within few
> seconds).
>
> I feel we can use DNS for this purpose, but doing load balance in
> realtime?

<snip>

I think you are looking the wrong way.  DNS doesn't change as quickly
as you are hoping it does.  There's ISP caches, OS caches, and
application caches.  Most of these even cache failed lookups and a lot
of times they also ignore TTL's.

I've done what you are thinking of (with the exception of the 10 idle
servers (which makes no sense to me)) with OpenBSD's relayd.  If you
want to spend lots of money then an F5 solution would do the trick as
well.

-Bryan