load balancing again

Wiley Sanders bind at wsanders.net
Tue Feb 28 01:03:57 UTC 2006

> the latest version of BIND removes duplicate records so essentially you are with 2 records, one for each address.

This is news to me. When did this change? We run 9.2.1 (I know,
ancient) and it shuffles through multiple A records just fine,
although the result appear neither precisely "random" nor "round
robin". I don't know if the results are "balanced" - they are,
however, "different" every time :-) . I suppose for truly random load
balancing, or for balancing based on some other performance metric,
you will need a specialized balancer. I seem to recall there are some
open source ones out there, including extensions to iptables. They
look hideously complex to me, I'd feel more comfortable buying a
couple of used ServerIrons on EBay!

TFM says "The rrset-order statement is not yet fully implemented in
BIND 9. BIND 9 currently does not support "fixed" ordering." Looks
like it ought to work, at least approximately..

Remember you will have side effects from caching, unless you set your
TTLs to 0, so you will only see different responses when you "dig
@<authoritative server>" and not necessarily from your web browser.

-W Sanders

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