[dnsdist] Clarification on weight in newServer option
lists+powerdns.com at elitists.org
Fri Jul 28 09:13:37 UTC 2017
On Fri, Jul 28, 2017 at 2:04 AM, Remi Gacogne <remi.gacogne at powerdns.com> wrote:
> On 07/28/2017 10:30 AM, Frank Even wrote:
>>> That's not expected, especially since we keep no state to do the
>>> load-balancing. Which policy are you using, wrandom or whashed?
>> Whatever is default. Is whashed default? Here's my config (minus the
>> ACLs and setKey), it was simple for testing:
> OK, so the default load-balancing policy is leastOutstanding, sending
> queries to the server with the least outstanding queries, then the
> lowest order if there is a tie and finally the lowest latency. This
> policy doesn't use the weight at all, so it explains why your results
> were not conclusive.
> Ideally we should implement a weighted consistent hashing policy to deal
> with use cases such as yours. Willy Tarreau suggested it a few months
> ago and was kind enough to explain to me how it's done in HAProxy, but I
> haven't found the time to seriously look into it yet.
Interesting. Also explains the results I was just about to reply
with, which also seem to not be paying attention to weight after I
remove the ordered node:
# Name Address State Qps
Qlim Ord Wt Queries Drops Drate Lat Outstanding Pools
0 10.36.191.74:53 down 0.0
0 0 1000 19490 1 0.0 0.4 0
1 10.36.191.75:53 up 0.0
0 1 500 7 0 0.0 2.8 0
2 10.37.77.148:53 up 320.4
0 1 50 5426 0 0.0 0.6 0
I may very well have missed something, but a lot of this isn't clear
to me in the documentation. I appreciate the clarification though.
SO, if I understand correctly, if I want the weight variable to have
any meaning at all, I need to change the load balancing algorithm,
What policy would be best suited to using weights? Is that efficient?
Or should I just keep it like this, remove weights, and deploy an
Thanks for your help!
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