Application gateway rewrite rules

Question

we are using application gateway in our AKS cluster. The requirement is that we need to remove port number from request of an api .
for example
https://my-domain.com//v1/location - 200{"headers":{},"body":", X.X.X.X:24487: Name does not resolve","statusCode":"BAD_REQUEST","statusCodeValue":400}

from the above request we need to remove port number, Because of this port number our api is failing.

we tried rewrite rules to parse ports number but the set rule is removed when we have any service deployment / POD failure in the cluster. Thus, affecting the rule implementation.

Please suggest how to resolve this issue.
@SRIJIT-BOSE-MSFT can you help?

Answer 1

@Shreyas Arani , thanks for the reply.

Azure Application Gateway Ingress Controller annotations keep getting added/updated. Please check here for updated list of supported annotations. You can also stay up-to-date with release updates from Azure Application Gateway Ingress Controller here.

In this particular case,

Rewrite Rule Set

This annotation allows to assign an existing rewrite rule set to the corresponding request routing rule.

Usage

   appgw.ingress.kubernetes.io/rewrite-rule-set: <rewrite rule set>  

Example

   apiVersion: extensions/v1beta1  
   kind: Ingress  
   metadata:  
     name: go-server-ingress-bkprefix  
     namespace: test-ag  
     annotations:  
       kubernetes.io/ingress.class: azure/application-gateway  
       appgw.ingress.kubernetes.io/rewrite-rule-set: add-custom-response-header  
   spec:  
     rules:  
    - http:  
         paths:  
         - path: /  
           backend:  
             serviceName: go-server-service  
             servicePort: 8080  

Using this will ensure that the Ingress Controller takes the existing static rewrite rules on the Application Gateway into account and does not override this in the process of updates.

References:

• Issue #1003
• PR #1287

----
Hope this helps.

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Answer 2

@SRIJIT-BOSE-MSFT the documentation seems to be vague.
One the one hand it says add-custom-response-header, but it also says
This annotation allows to assign an existing rewrite rule set to the corresponding request routing rule.

What should be the value for this annotation ?
Should it be a custom header something like

appgw.ingress.kubernetes.io/rewrite-rule-set: 'myheader:value'  

Or I need to create a Rewrite Set and mention it's name in the value,

appgw.ingress.kubernetes.io/rewrite-rule-set: 'myrewriteset'  

----------

In fact, I tried both the options, and it did not work.
For second option, I could not see any Associations of rule with the rewrite set after applying the ingress rule.

Container image I am using is: azure-application-gateway/kubernetes-ingress:1.5.0
AKS version: 1.21

Could someone explain how to make this work ?