API Gateway -> VPC Link (NLB) --> ALB --> EC2/ECS

This is a sample setup for APIGateway with VPCLink (NLB) to ALB into EC2. NLB, ALB and EC2 are all in private subnet.

Steps:

• npm run build

• cdk deploy and wait for the Cloudformation Stack deployment to complete

• Please update the ALB IPs in the nlb-alb-stack.ts under lib

  const ALB_IP1= "" 
  const ALB_IP2= ""
  

• You can get the ALB IPs by using the AWS Systems Manager Run Command

  • Run Command

  • Choose AWS-RunShellScript

  • Command Parameters as dig +short {internal-alb-dns}

  • Targets - Choose instance manually and select private-instance

  • Leave the rests as default

  • Click Run and check the output

    

• Update the ALB IPs and redeploy.

This could also be automated using Systems Manager Automation (work in progress) or alternatively, you can use the Lambda function from this blog article to have the NLB auto-register ALB IPs (when it changes) https://aws.amazon.com/blogs/networking-and-content-delivery/using-static-ip-addresses-for-application-load-balancers/

Other useful commands

• npm run build compile typescript to js
• npm run watch watch for changes and compile
• npm run test perform the jest unit tests
• cdk deploy deploy this stack to your default AWS account/region
• cdk diff compare deployed stack with current state
• cdk synth emits the synthesized CloudFormation template