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We are using Azure Application Gateway as the ingress controller to our AKS cluster and we have been hitting this issue occasionally.

"The number of BackendHttpSettings exceeds the maximum allowed value and the maximum allowed is 100."

Does AGIC have any tier to support more settings count?

Jithin Zachariah
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    All references go to [azure application gateway - limits](https://learn.microsoft.com/en-us/azure/azure-resource-manager/management/azure-subscription-service-limits#application-gateway-limits) which is stated `Back-end HTTP settings 100`. Best option and approach is to reach out to MicroSoft support and they will answer for sure if it's possible anyhow. – moonkotte Sep 06 '21 at 13:53
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    Yeah, the limit is 100. I am looking for a solution to tackle this limit . As of now, Azure doesn't show any tiers to more than 100 HTTP settings. – Jithin Zachariah Sep 08 '21 at 10:16

1 Answers1

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Thanks for the Comment Jithin.

Based on the Repro from our environment, We had chance to choose only among 4 Tiers for the Application gateway Ingress Controller.

Tried with Standard V2 and we do not have options to increase the Backend HTTP Settings more than Maximum 100 limit.

Tiers Available:

enter image description here

Possible Solution:

When creating the 1)AGW IC we would add both servers to the backend address pool 2) Create a probe for each subdomain 3) Create a backendhttpsetting with each probe? Or create with no probe?

Other Option:

You can achieve this with multiple http settings, each with its own probe. For example if you have a.domain.com and b.domain.com running on the same set of backend servers, you would create two http settings and two custom probes. Probe1 would probe on a.domain.com as host name and probe2 with b.domain.com. Your backend pool will be a single backend pool with the two servers. Now you can create two rules and attach the two probes & settings to the rules and point them to the same backend pool. The probe will only mark down a.domain.com or b.domain.com but not the whole VM. Hope that helps.

Reference SO Thread: Azure Application Gateway Probe Configuration

SureshBabu
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    Thanks for the reply, I get the idea that it is a warning message. But I am looking for a solution where I could scale it up to support more than 100 HTTP settings. We have use cases to add more than 100 HTTP setting per gateway – Jithin Zachariah Sep 08 '21 at 10:15
  • Thanks Jithin for your feedback. I have now edited the Answer based on the repro from our environment with available Tiers to increase the limit. – SureshBabu Sep 10 '21 at 07:29