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From benoit lair <>
Subject Re: Netscaler & VPC and multiple inter tiers LB
Date Fri, 05 Sep 2014 13:03:20 GMT
Hi Francois,

Thanks for your response. So i do not need to do deeper tests in order to
confirm what i thought. You confirmed all that i feared. As you said it is
a very huge problem.

I can understand the problematic to have subnet overlapping with several
vpc (although you have several users and not just a sysops dept wanting to
manage several vpcs). Here again, it is strange, because vpc tiers are
vlans isolated, so you can have several times the same subnet present in
two differents vpcs, with 802.1Q isolation, even the netscaler could manage
this without trouble, isn't it ?

Now reducing the opportunities with my netscaler, i don't understand why i
can't do Ns-Lb ith all my tiers inside a vpc :

I want to host a web application according to the 3-tier model (web reverse
proxy, web app server, sql database server), how can i exploit correctly
the tcp multiplexing feature of the Netscaler if once passed the web
reverse proxy tier, i do pass my request to a simple (too ?) lb internal vm
in order to contact my web app server ?

However i imagined to do some internal lb for the external tier (web
reverse proxy) and to pass the http(s) request to my web app server through
the netscaler. But here again when using NS with VPC, it can only be used
for external LB and not internal LB.

Would you have another solution for this ? (a tweak into mgmt server db) Or
is it just impossible to realize ? Although i have 2 Netscaler into my VPC
? (one for the web reverse proxy tier, another for the web app tier)

Thanks for your responses.


2014-09-05 13:35 GMT+02:00 Francois Gaudreault <>:

> Hi Benoit,
> The limitations that you describes are exactly what the implementation is.
> Dedicated VPX per VPC, only public LB for one tier. However, there is a
> reasoning behind this. Since users can control their tier subnets, you may
> have overlapping. That's why you can't have a shared NetScaler for the VPCs.
> You can't do inter-tier load balancing using the NetScaler if you have it
> inside CloudStack. To be honest, we also feel this is a huge problem, and
> we will likely look at our options. You need to use the Internal LB for
> that piece.
> Hope it helps/confirms your thoughts :)
> Francois
> On 2014-09-05, 6:03 AM, benoit lair wrote:
>> Hello Folks,
>> I'm testing Netscaler VPX with acs 4.3. I have several VPCs deployed into
>> my cloud.
>> I would like to get my netscaler working with my vpcs.
>> So from what i have tested, it seems that :
>> - i can't share a VPX with more than one VPC ?
>> - in order to get my netscaler working with my vpc, i need to declare it
>> "dedicated". So it can't be used both with vpc tiers and isolated
>> networks ?
>> - i can use netscaler with a vpc only with "public" tier (means external
>> tier)
>> Can you confirm these limitations, or is it due to a misconfiguration of
>> my
>> own networks offerings ?
>> So another question is :
>> How can i achieve ns-lb with several tiers in a vpc ?
>> I have a vpc with web-tier, app-tier and sql-tier :
>> how can i have in the same time, nslb between outside and web-tier, nslb
>> between web-tier and app-tier and nslb between app-tier and sql-tier,
>> having only one VPX ?
>> Thanks four your lights.
>> Regards, Benoit.
> --
> Francois Gaudreault
> Gestionnaire de Produit | Product Manager - Cloud Platform & Services
> t:514-629-6775
> CloudOps Votre partenaire infonuagique | Cloud Solutions Experts
> 420 rue Guy | Montreal | Quebec | H3J 1S6
> w: | tw: @CloudOps_

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