Deploy NestJS App to Amazon ECS

In this lesson, we’ll configure an AWS ALB and learn how to deploy our NestJS app image to Amazon ECS. An ALB is an AWS service that distributes incoming application traffic across multiple targets, such as ECS containers, based on routing rules and health checks.

Prerequisites

Before we start, please ensure that the tasks in the ECR and ECS Configuration lesson have been completed successfully.

Create an ALB

When we create our AWS account, AWS automatically creates a default VPC with three subnets and a security group. Here, we’ll use the default VPC, subnets, and the default security group for the sake of simplicity. In a real-world project, we might like to create a separate VPC and security group depending on the project’s infrastructure.

Creating a target group and an ALB is a common practice when deploying applications to ECS.

A target group in AWS is a logical grouping of targets—such as ECS containers or IP addresses that serve as the destination for requests forwarded by a load balancer—allowing for dynamic scaling and efficient traffic distribution. An ALB distributes incoming traffic across multiple targets, which ensures the workload is evenly distributed, improving the availability and responsiveness of the application.

First, let’s create a target group: address-book-tg.

The command above creates a new target group named address-book-tg.

• aws elbv2 create-target-group: It initiates the creation of a new target group for an ALB.

• --name address-book-tg: It specifies the name of the target group as address-book-tg.

• --protocol HTTP: It specifies that the target group uses the HTTP protocol for communication.

• --port 3000: It sets the port on which the ECS containers will receive traffic within the target group.

• --target-type ...