Create Ingress With Health Check¶

Health check on target groups can be controlled with following annotations:

Annotation Format¶

Annotation keys and values can only be strings. Advanced format should be encoded as below:

boolean: 'true' # Must be quoted
integer: '42' # Must be quoted
stringList: s1,s2,s3
stringMap: k1=v1,k2=v2
json: 'jsonContent' # Must be quoted

Docker Images¶

Here is the Docker Image used in this tutorial: reyanshkharga/nodeapp:v1

Step 1: Create a Deployment¶

First, let's create a deployment as follows:

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apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-deployment
spec:
  replicas: 2
  selector:
    matchLabels:
      app: demo
  template:
    metadata:
      labels:
        app: demo
    spec:
      containers:
      - name: nodeapp
        image: reyanshkharga/nodeapp:v1
        imagePullPolicy: Always
        ports:
          - containerPort: 5000

Apply the manifest to create the deployment:

kubectl apply -f my-deployment.yml

Verify deployment and pods:

# List deployments
kubectl get deployments

# List pods
kubectl get pods

Step 2: Create a NodePort Service¶

Let's create a NodePort service as follows:

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apiVersion: v1
kind: Service
metadata:
  name: my-nodeport-service
spec:
  type: NodePort
  selector:
    app: demo
  ports:
    - port: 5000
      targetPort: 5000

Apply the manifest to create the NodePort service:

kubectl apply -f my-nodeport-service.yml

Verify service:

kubectl get svc

If you don't explicitly provide a nodePort, you'll observe that the service is automatically assigned one. However, if desired, you can specify a specific nodePort.

Step 3: Create Ingress¶

Now that we have the service ready, let's create an Ingress object with health check:

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apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ingress
  annotations:
    # Load Balancer Annotations
    alb.ingress.kubernetes.io/scheme: internet-facing # Default value is internal
    alb.ingress.kubernetes.io/tags: Environment=dev,Team=DevOps # Optional
    alb.ingress.kubernetes.io/load-balancer-name: my-load-balancer # Optional
    # Health Check Annotations
    alb.ingress.kubernetes.io/healthcheck-protocol: HTTP
    alb.ingress.kubernetes.io/healthcheck-port: traffic-port
    alb.ingress.kubernetes.io/healthcheck-path: /health
    alb.ingress.kubernetes.io/healthcheck-interval-seconds: '5'
    alb.ingress.kubernetes.io/healthcheck-timeout-seconds: '2'
    alb.ingress.kubernetes.io/success-codes: '200'
    alb.ingress.kubernetes.io/healthy-threshold-count: '2'
    alb.ingress.kubernetes.io/unhealthy-threshold-count: '2'
spec:
  ingressClassName: alb
  rules:
  - http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: my-nodeport-service
            port:
              number: 5000

Observe the following:

1. We have used annotations to specify load balancer and target group attributes
2. We have one rule that matches / path and then routes traffic to my-nodeport-service
3. We have specified health check parameters for the target group

Apply the manifest to create ingress:

kubectl apply -f my-ingress.yml

Verify ingress:

kubectl get ingress
{OR}
kubectl get ing

Step 4: Verify AWS Resources in AWS Console¶

Visit the AWS console and verify the resources created by AWS Load Balancer Controller.

Pay close attention to the health check configuration of the target group that ingress created.

Note that the Load Balancer takes some time to become Active.

Also, verify that the ALB was created by AWS Load Balancer Controller. You can check the events in the logs as follows:

kubectl logs -f deploy/aws-load-balancer-controller -n aws-load-balancer-controller --all-containers=true

Step 5: Access App Via Load Balancer DNS¶

Once the load balancer is in Active state, you can hit the load balancer DNS and verify if everything is working properly.

Access the load balancer DNS by entering it in your browser. You can get the load balancer DNS either from the AWS console or the Ingress configuration.

Try accessing the following paths:

# Root path
<load-balancer-dns>/

# Health path
<load-balancer-dns>/health

# Random generator path
<load-balancer-dns>/random

Troubleshooting¶

If you don't see the load balancer in the AWS console, this means the ingress has some issue. To identify the underlying issue, you can examine the logs of the controller as follows:

# Describe the ingress
kubectl describe ing my-ingress

# View aws load balancer controller logs
kubectl logs -f deploy/aws-load-balancer-controller -n aws-load-balancer-controller --all-containers=true

Clean Up¶

Assuming your folder structure looks like the one below:

|-- manifests
│   |-- my-deployment.yml
│   |-- my-nodeport-service.yml
│   |-- my-ingress.yml

Let's delete all the resources we created:

kubectl delete -f manifests/