# Integrations

## Istio

### Configuration Steps

1. **Proxy Service in Virtual Service:**

   - Within the Istio virtual service definition, add a proxy service as a route destination.
   - Set the host of this proxy service to `keda-add-ons-http-interceptor-proxy`` (the KEDA HTTP Addon interceptor service).
   - Set the port to `8080`` (the default interceptor port).

**Example yaml**

```yaml
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: example
  namespace: default
spec:
  http:
    - route:
        - destination:
            host: keda-add-ons-http-interceptor-proxy
            port: 8080
```

2. **Namespace Alignment:**

   - Ensure that both the KEDA HTTP Addon and the Istio virtual service are deployed within the same Kubernetes namespace. This ensures proper communication between the components.

### Behavior

- When a user makes a request, the Istio virtual service routes it to the KEDA HTTP Addon interceptor service.
- The interceptor service captures request metrics and relays them to the KEDA scaler component.
- Based on these metrics and scaling rules defined in the KEDA configuration, the KEDA scaler automatically scales the target workload (e.g., a deployment) up or down (including scaling to zero).

### Troubleshooting Tips

1. **Error: `context marked done while waiting for workload reach > 0 replicas`**

   - This error indicates that the `KEDA_CONDITION_WAIT_TIMEOUT` value (default: 20 seconds) might be too low. The workload scaling process may not be complete within this timeframe.
   - To increase the timeout:
     - If using Helm, adjust the `interceptor.replicas.waitTimeout`` parameter (see reference below).
     - Reference: [https://github.com/kedacore/charts/blob/main/http-add-on/values.yaml#L139](https://github.com/kedacore/charts/blob/main/http-add-on/values.yaml#L139)

2. **502 Errors with POST Requests:**

   - You might encounter 502 errors during POST requests when the request is routed through the interceptor service. This could be due to insufficient timeout settings.
   - To adjust timeout parameters:
     - If using Helm, modify the following parameters (see reference below):
       - `KEDA_HTTP_CONNECT_TIMEOUT`
       - `KEDA_RESPONSE_HEADER_TIMEOUT`
       - `KEDA_HTTP_EXPECT_CONTINUE_TIMEOUT`
     - Reference: [https://github.com/kedacore/charts/blob/main/http-add-on/values.yaml#L152](https://github.com/kedacore/charts/blob/main/http-add-on/values.yaml#L152)

3. **Immediate Scaling Down to Zero:**
   - If `minReplica` is set to 0 in the HTTPScaledObject, the application will immediately scale down to 0.
   - There's currently no built-in mechanism to delay this initial scaling.
   - A PR is in progress to add this support: [https://github.com/kedacore/keda/pull/5478](https://github.com/kedacore/keda/pull/5478)
   - As a workaround, keep `minReplica` initially as 1 and update it to 0 after the desired delay.

---

## Azure Front Door

### Configuration Steps

1. **Service Setup in Front Door:**
   - Set up Azure Front Door to route traffic to your AKS cluster.
   - Ensure that the `Origin Host` header matches the actual AKS host. Front Door enforces case-sensitive routing, so configure the `Origin Host` exactly as the AKS host name.

2. **KEDA HTTP Add-on Integration:**
   - Use an `HTTPScaledObject` to manage scaling based on incoming traffic.
   - Front Door should route traffic to the KEDA HTTP Add-on interceptor service in your AKS cluster.

3. **Case-Sensitive Hostnames:**
   - Be mindful that Azure Front Door treats the `Origin Host` header in a case-sensitive manner.
   - Ensure consistency between the AKS ingress hostname (e.g., `foo.bar.com`) and Front Door configuration.

### Troubleshooting Tips

- **404 Error for Hostnames with Different Case:**
   - Requests routed with inconsistent casing (e.g., `foo.Bar.com` vs. `foo.bar.com`) will trigger 404 errors. Make sure the `Origin Host` header matches the AKS ingress host exactly.
   - If you encounter errors like `PANIC=value method k8s.io/apimachinery/pkg/types.NamespacedName.MarshalLog called using nil *NamespacedName pointer`, verify the `Origin Host` header configuration.

### Expected Behavior

- Azure Front Door routes traffic to AKS based on a case-sensitive host header.
- The KEDA HTTP Add-on scales the workload in response to traffic, based on predefined scaling rules.


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