Redirect Azure App GW from short name to FQDN

Question

I have an AKS cluster paired with Azure Application GW with AGIC. Am looking for a simple way to redirect from short name to FQDN for a site. So for example,

contoso -> contoso.com

My assumption is that if I create any manual rules directly in Az App GW, it will get overwritten by AGIC on the next sync. I am not migrated to ALB since we are using private IPs.

Is there an easy yaml definition to achieve this redirect?

In the Ingress definition, I tried the following annotation

appgw.ingress.kubernetes.io/redirect-target: "contoso.com"

But that doesnt seem to work.

Other option would be to use an nginx container that manages redirects. But was hoping there is a simpler solution

Answer 1

You're right that manually configuring rules in Azure Application Gateway (App GW) won’t work because AGIC (Application Gateway Ingress Controller) syncs resources from Kubernetes and overwrites manual changes.

Instead, the best approach is to use Gateway API and HTTPRoute resources to handle redirections within the Kubernetes setup.

to redirect from "contoso" to "contoso.com" in Azure Application Gateway (AGIC) use Gateway API and HTTPRoute to define a rule that redirects the short name to the FQDN.

Refer this MSDOC to use URL Redirect for Azure Application Gateway for Containers.

Below is the sample YAML Code for Redirect

apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: gateway-01
  namespace: test-infra
  annotations:
    alb.networking.azure.io/alb-namespace: alb-test-infra
    alb.networking.azure.io/alb-name: alb-test
spec:
  gatewayClassName: azure-alb-external
  listeners:
  - name: http-listener
    port: 80
    protocol: HTTP
    allowedRoutes:
      namespaces:
        from: Same
  - name: https-listener
    port: 443
    protocol: HTTPS
    allowedRoutes:
      namespaces:
        from: Same
    tls:
      mode: Terminate
      certificateRefs:
      - kind: Secret
        group: ""
        name: listener-tls-secret
---
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: http-to-https-contoso-redirect
  namespace: test-infra
spec:
  parentRefs:
  - name: gateway-01
    sectionName: http-listener
  hostnames:
  - "contoso"
  rules:
  - filters:
    - type: RequestRedirect
      requestRedirect:
        hostname: "contoso.com"
        scheme: https
        statusCode: 301