How do I put API Gateway in front of ALB and then to ECS/EC2?

Question

I am Building a solution, where I have 10-15 micro-services REST Applications running in ECS Container and few will be in EC2. I am using Cognito as API Gateway authentication. Now UI Application will send the request to API Gateway, which in turn connect with REST Application and returns the response.

I have tried implementing API Gateway authentication with Cognito and I am able to connect to the REST endpoint running in EC2.

Now I need a solution like API Gateway -> Application Load Balancer -> Target Group -> ECS/EC2 will be running in Public Subnet.

How do I Configure this?

Am I following the correct approach?

Answer 1

• Api getway you need to expose your microservice and cognito authorizer will take care authentication and authorization.

To register your instances using the console

• Open the Amazon EC2 console at https://console.aws.amazon.com/ec2/ .

• On the navigation pane, under LOAD BALANCING, choose Load Balancers.

• Select your load balancer.

• In the bottom pane, select the Instances tab.

• Choose Edit Instances.

• Select the instance to register with your load balancer.

• Choose Save.

https://docs.aws.amazon.com/elasticloadbalancing/latest/classic/elb-deregister-register-instances.html

https://docs.aws.amazon.com/AmazonECS/latest/userguide/create-load-balancer.html

https://docs.aws.amazon.com/AmazonECS/latest/userguide/create-application-load-balancer.html

Answer 2

When you setup your API Gateway,

Create a proxy resource with a greedy path {proxy+}. Set ANY Method on the proxy resource. Set the endpoint URL to your ALB endpoint.

Ex. ENDPOINT URL: https://alb-example-123456789.us-east-1.elb.amazonaws.com/example/ {proxy}

For more details, refer to this links: https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-set-up-simple-proxy.html https://docs.aws.amazon.com/apigateway/latest/developerguide/setup-http-integrations.html?shortFooter=true