Troubleshooting: Installing a simple application

NOTE: Application Gateway for Containers has been released, which introduces numerous performance, resilience, and feature changes. Please consider leveraging Application Gateway for Containers for your next deployment.

Azure Cloud Shell is the most convenient way to troubleshoot any problems with your AKS and AGIC installation. Launch your shell from shell.azure.com or by clicking the link:

In the troubleshooting document, we will debug issues in the AGIC installation by installing a simple application step by step and check the output as we go along. The steps below assume:

• You have an AKS cluster, with Advanced Networking enabled
• AGIC has been installed on the AKS cluster
• You already hav an App Gateway on a VNET shared with your AKS cluster

To verify that the App Gateway + AKS + AGIC installation is setup correctly, deploy the simplest possible app:

```bash cat <<EOF | kubectl apply -f - apiVersion: v1 kind: Pod metadata: name: test-agic-app-pod labels: app: test-agic-app spec: containers: - image: "mcr.microsoft.com/dotnet/samples:aspnetapp" name: aspnetapp-image ports: - containerPort: 80 protocol: TCP

---

apiVersion: v1 kind: Service metadata: name: test-agic-app-service spec: selector: app: test-agic-app ports: - protocol: TCP port: 80 targetPort: 80

---

apiVersion: networking.k8s.io/v1 kind: Ingress metadata: name: test-agic-app-ingress annotations: kubernetes.io/ingress.class: azure/application-gateway spec: rules: - host: test.agic.contoso.com http: paths: - path: / backend: service: name: test-agic-app-service port: number: 80 pathType: Exact EOF ```

Copy and paste all lines at once from the script above into a Azure Cloud Shell. Please ensure the entire command is copied - starting with cat and including the last EOF.

After a successful deployment of the app above your AKS cluster will have a new Pod, Service and an Ingress.

Get the list of pods with Cloud Shell: kubectl get pods -o wide. We expect for a pod named 'test-agic-app-pod' to have been created. It will have an IP address. This address must be within the VNET of the App Gateway, which is used with AKS.

Get the list of services: kubectl get services -o wide. We expect to see a service named 'test-agic-app-service'.

Get the list of the ingresses: kubectl get ingress. We expect an Ingress resource named 'test-agic-app-ingress' to have been created. The resource will have a host name 'test.agic.contoso.com'.

One of the pods will be AGIC. kubectl get pods will show a list of pods, one of which will begin with 'ingress-azure'. Get all logs of that pod with kubectl logs <name-of-ingress-controller-pod> to verify that we have had a successful deployment. A successful deployment would have added the following lines to the log:

I0927 22:34:51.281437 1 process.go:156] Applied App Gateway config in 20.461335266s I0927 22:34:51.281585 1 process.go:165] cache: Updated with latest applied config. I0927 22:34:51.282342 1 process.go:171] END AppGateway deployment

Alternatively, from Cloud Shell we can retrieve only the lines indicating successful App Gateway configuration with kubectl logs <ingress-azure-....> | grep 'Applied App Gateway config in', where <ingress-azure....> should be the exact name of the AGIC pod.

App Gateway will have the following configuration applied:

• Listener:

• Routing Rule:

• Backend Pool:

• There will be one IP address in the backend address pool and it will match the IP address of the Pod we observed earlier with kubectl get pods -o wide

Finally we can use the cURL command from within Cloud Shell to establish an HTTP connection to the newly deployed app:

1. Use kubectl get ingress to get the Public IP address of App Gateway
2. Use curl -I -H 'Host: test.agic.contoso.com' <publitc-ip-address-from-previous-command>

A result of HTTP/1.1 200 OK indicates that the App Gateway + AKS + AGIC system is working as expected.

Inspect Kubernetes Installation

Pods, Services, Ingress

Application Gateway Ingress Controller (AGIC) continuously monitors the following Kubernetes resources: Deployment or Pod, Service, Ingress

The following must be in place for AGIC to function as expected:

1. AKS must have one or more healthy pods. Verify this from Cloud Shell with kubectl get pods -o wide --show-labels If you have a Pod with an aspnetapp, your output may look like this:

   ```bash $> kubectl get pods -o wide --show-labels

   NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES LABELS aspnetapp 1/1 Running 0 17h 10.0.0.6 aks-agentpool-35064155-1 app=aspnetapp ```

2. One or more services, referencing the pods above via matching selector labels. Verify this from Cloud Shell with kubectl get services -o wide

   ```bash $> kubectl get services -o wide --show-labels

   NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR LABELS aspnetapp ClusterIP 10.2.63.254 80/TCP 17h app=aspnetapp ```

3. Ingress, annotated with kubernetes.io/ingress.class: azure/application-gateway, referencing the service above Verify this from Cloud Shell with kubectl get ingress -o wide --show-labels

   ```bash $> kubectl get ingress -o wide --show-labels

   NAME HOSTS ADDRESS PORTS AGE LABELS aspnetapp * 80 17h ```

4. View annotations of the ingress above: kubectl get ingress aspnetapp -o yaml (substitute aspnetapp with the name of your ingress)

   ```bash $> kubectl get ingress aspnetapp -o yaml

   apiVersion: networking.k8s.io/v1 kind: Ingress metadata: annotations: kubernetes.io/ingress.class: azure/application-gateway name: aspnetapp spec: defaultBackend: service: name: aspnetapp port: number: 80 ```

   The ingress resource must be annotated with kubernetes.io/ingress.class: azure/application-gateway.

Verify Observed Nampespace

• Get the existing namespaces in Kubernetes cluster. What namespace is your app running in? Is AGIC watching that namespace? Refer to the Multiple Namespace Support documentation on how to properly configure observed namespaces.

  ```bash

  What namespaces exist on your cluster

  kubectl get namespaces

  What pods are currently running

  kubectl get pods --all-namespaces -o wide ```

• The AGIC pod should be in the default namespace (see column NAMESPACE). A healthy pod would have Running in the STATUS column. There should be at least one AGIC pod.

  ```bash

  Get a list of the Application Gateway Ingress Controller pods

  kubectl get pods --all-namespaces --selector app=ingress-azure ```

• If the AGIC pod is not healthy (STATUS column from the command above is not Running):

• get logs to understand why: kubectl logs <pod-name>
• for the previous instance of the pod: kubectl logs <pod-name> --previous

• describe the pod to get more context: kubectl describe pod <pod-name>

• Do you have a Kubernetes Service and Ingress resources?

  ```bash

  Get all services across all namespaces

  kubectl get service --all-namespaces -o wide

  Get all ingress resources across all namespaces

  kubectl get ingress --all-namespaces -o wide ```

• Is your Ingress annotated with: kubernetes.io/ingress.class: azure/application-gateway? AGIC will only watch for Kubernetes Ingress resources that have this annotation.

  ```bash

  Get the YAML definition of a particular ingress resource

  kubectl get ingress --namespace -o yaml ```

• AGIC emits Kubernetes events for certain critical errors. You can view these:

• in your terminal via kubectl get events --sort-by=.metadata.creationTimestamp
• in your browser using the Kubernetes Web UI (Dashboard)