Azure AKS Application Gateway 502 bad gateway - kubernetes

Question

I have been following the tutorial here:
MS Azure
This is fine. However deploying a local config file I get a "502 Gate Way" error. This config has been fine and works as expected.
Can anyone see anything obvious with this: At this point I don't know where to start.
I am trying to achieve using the ingress controller that is Application gateway. Then add deployments and apply additional ingress rules
apiVersion: apps/v1
kind: Deployment
metadata:
name: one-api
namespace: default
annotations:
imageregistry: "gcr.io/google-samples/hello-app:1.0"
spec:
replicas: 3
selector:
matchLabels:
run: one-api
template:
metadata:
labels:
run: one-api
spec:
containers:
- image: gcr.io/google-samples/hello-app:1.0
imagePullPolicy: IfNotPresent
name: one-api
ports:
- containerPort: 80
protocol: TCP
---
apiVersion: v1
kind: Service
metadata:
name: one-api
namespace: default
spec:
ports:
- port: 80
protocol: TCP
targetPort: 80
selector:
run: one-api
type: NodePort
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: two-api
namespace: default
annotations:
imageregistry: "gcr.io/google-samples/hello-app:1.0"
spec:
replicas: 3
selector:
matchLabels:
run: two-api
template:
metadata:
labels:
run: two-api
spec:
containers:
- image: gcr.io/google-samples/hello-app:1.0
imagePullPolicy: IfNotPresent
name: two-api
ports:
- containerPort: 80
protocol: TCP
---
apiVersion: v1
kind: Service
metadata:
name: two-api
namespace: default
spec:
ports:
- port: 80
protocol: TCP
targetPort: 80
selector:
run: two-api
type: NodePort
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: strata-2022
labels:
app: my-docker-apps
annotations:
kubernetes.io/ingress.class: azure/application-gateway
spec:
rules:
- http:
paths:
- path: /
pathType: Prefix
backend:
service:
name: one-api
port:
number: 80
- path: /two-api
pathType: Prefix
backend:
service:
name: two-api
port:
number: 80
Output of: kubectl describe ingress strata-2022
Name: strata-2022
Labels: app=my-docker-apps
Namespace: default
Address: 51.142.191.83
Ingress Class:
Default backend:
Rules:
Host Path Backends
/ one-api:80 (10.224.0.15:80,10.224.0.59:80,10.224.0.94:80)
/two-api two-api:80 (10.224.0.13:80,10.224.0.51:80,10.224.0.82:80)
Annotations: kubernetes.io/ingress.class: azure/application-gateway
Events:
kubectl describe ingress
Name: strata-2022
Labels: app=my-docker-apps
Namespace: default
Address: 51.142.191.83
Ingress Class: <none>
Default backend: <default>
Rules:
Host Path Backends
---- ---- --------
*
/ one-api:80 (10.224.0.15:80,10.224.0.59:80,10.224.0.94:80)
/two-api two-api:80 (10.224.0.13:80,10.224.0.51:80,10.224.0.82:80)
Annotations: kubernetes.io/ingress.class: azure/application-gateway
Events: <none>
Commands used to create AKS using Azure CLI.
az aks create -n myCluster -g david-tutorial --network-plugin azure --enable-managed-identity -a ingress-appgw --appgw-name testApplicationGateway --appgw-subnet-cidr "10.225.0.0/16" --generate-ssh-keys
// Get credentials and switch to this context
az aks get-credentials -n myCluster -g david-tutorial
// This line is from the tutorial -- this works as expected
//kubectl apply -f https://raw.githubusercontent.com/Azure/application-gateway-kubernetes-ingress/master/docs/examples/aspnetapp.yaml
// This is what i ran. It works locally
kubectl apply -f nano new-deploy.yaml
// Get address
kubectl get ingress
kubectl get configmap

Answer 1

I tried recreating the same setup on my end, and I could identify the following issue right after running the same az aks create command: All the instances in one or more of your backend pools are unhealthy.
Since this appeared to indicate that the backend pools are unreachable, it was strange at first so I tried to look at the logs of one of the pods based on the hello-app images you were using and noticed this right away:
> kubectl logs one-api-77f9b4b9f-6sv6f
2022/08/12 00:22:04 Server listening on port 8080
Hence, my immediate thought was that maybe in the Docker image that you are using, nothing is configured to listen on port 80, which is the port you are using in your kubernetes resources definition.
After updating your Deployment and Service definitions to use port 8080 instead of 80, everything worked perfectly fine and I started getting the following response in my browser:
Hello, world!
Version: 1.0.0
Hostname: one-api-d486fbfd7-pm8kt
Below you can find the updated YAML file that I used to successfully deploy all the resources:
apiVersion: apps/v1
kind: Deployment
metadata:
name: one-api
namespace: default
annotations:
imageregistry: "gcr.io/google-samples/hello-app:1.0"
spec:
replicas: 3
selector:
matchLabels:
run: one-api
template:
metadata:
labels:
run: one-api
spec:
containers:
- image: gcr.io/google-samples/hello-app:1.0
imagePullPolicy: IfNotPresent
name: one-api
ports:
- containerPort: 8080
protocol: TCP
---
apiVersion: v1
kind: Service
metadata:
name: one-api
namespace: default
spec:
ports:
- port: 8080
protocol: TCP
targetPort: 8080
selector:
run: one-api
type: NodePort
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: two-api
namespace: default
annotations:
imageregistry: "gcr.io/google-samples/hello-app:1.0"
spec:
replicas: 3
selector:
matchLabels:
run: two-api
template:
metadata:
labels:
run: two-api
spec:
containers:
- image: gcr.io/google-samples/hello-app:1.0
imagePullPolicy: IfNotPresent
name: two-api
ports:
- containerPort: 8080
protocol: TCP
---
apiVersion: v1
kind: Service
metadata:
name: two-api
namespace: default
spec:
ports:
- port: 8080
protocol: TCP
targetPort: 8080
selector:
run: two-api
type: NodePort
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: strata-2022
labels:
app: my-docker-apps
annotations:
kubernetes.io/ingress.class: azure/application-gateway
spec:
rules:
- http:
paths:
- path: /
pathType: Prefix
backend:
service:
name: one-api
port:
number: 8080
- path: /two-api
pathType: Prefix
backend:
service:
name: two-api
port:
number: 8080