Load Balancing and Varnish

[Hettwer, Marian]

On 26.06.12 19:40, "Hugo Cisneiros (Eitch)" <hugo.cisneiros at gmail.com>
wrote:

>On Tue, Jun 26, 2012 at 1:46 PM, Allan Brand <allan.brand at gmail.com>
>wrote:
>> I'm new to Varnish and I've seen a number of discussions where Varnish
>> is used in conjunction with a load balancer in the following manner:
>> [LB] -> [Varnish] -> [www 1-n]
>>
>> I'm guessing that Varnish is running locally on the www hosts?  If
>> not, Is there any reason why placing Varnish in front of the load
>> balancers instead would not be ideal?
>> [Varnish] -> [LB} -> [www 1-n]
>
>Usually you use LB in front of varnish for high availability cases.
>Then, if a varnish fails, the other will take over all the work.
>
>But there's no problem using Varnish as a load balancer as it does a
>great job, as others said in this thread. But you must pay attention
>to the fail over/load balancing on the varnish as well :-)

I'm really missing the functionality of easily taking a backend out of
load balancing.
And I'm talking about gracefully going out of load balancing.
As in: Established connections are still allowed, but new connections are
denied.

Doing it to "destroy" the probe url doesn't sound like a clean way.
And rebuilding the vcl part with the backend definition doesn't sound cool
either.

That's sad, then apart from that, varnish is doing great as a load
balancer :)
And I do use it in production with machines were taking them hard out of
load balancing doesn't hurt.

Cheers,
Marian