Hi Benoit,
On Tue, Oct 17, 2017 at 04:17:42AM +0200, Benoit GEORGELIN - Association
Web4all wrote:
> Hi members of the list ,
>
> I would like to know if you have any recommendation about this problem I have
> .
> I'm running haproxy with a backend of apache2 web servers to loadbalance HTTP
> services
>
> In this model, I have better performance with "balance source" so I visitor
> have the content delivered from the same server.
> But I have a issue when a "source" kind of over talk to a website . This can
> make one of the HTTP in the backend to become slower for exemple as it handle
> too much connections. And as I balance with "source" it will stay and stick
> to that server in the backend
>
> So I was thinking, I'm gonna use "maxcon" to the servers in that backend ,
> but it does not solve my problem from a visitor point of view. The visitor
> will be add in "queue" and when a slot will be available in this backend for
> that server, pages will be delivered.
> At the end, the visitor will have a wait time.
>
> My question is, would it be possible to have an option that could be use with
> "balance source" but if "maxcon" reach 90% then force redispatch :)
> Or it there any available option that could help in this scenario?
I think you can use the consistent hashing with the hash-balance-factor
parameter. It was designed for URL-based load balancing for caches and
remains sticky as much as possible but tries to balance the load as well
and accepts to break the hash to ensure a smoother load. I never thought
about using it with "balance source" but I don't see any reason why it
wouldn't work, and your use case falls exactly in its use case. So in
short, try to do something like this :
balance source
hash-type consistent
hash-balance-factor 125 # highest load not more than 125% of average
Please check the doc for this last keyword, it's well explained.
Regards,
Willy
