AWS: Learning how to deploy a simple ECS Fargate service

Introduction

I've never deployed a Service to AWS ECS Fargate before, but today I decided to give it a try. From what I've read, Fargate allows you to run Docker containers in a serverless manner (i.e., without needing to manage EC2 instances). This is similar to AWS Lambda, except that Fargate deploys containers and does not have the short-lived lifecycle (up to a 15-minute limit) that AWS Lambda functions have.

All the code below can be found in this GitHub repo.

Step 1: Writing the Service Code

First, I needed a Service to deploy.

I wrote a simple Express server using a Node.js runtime. I tested it locally (by running node index.js in the terminal) and verified that it was able to return "Hello World!" when I visited http://localhost:3000/ in a browser.

// index.js

const express = require('express');
const app = express();

app.get('/', (req, res) => {
  res.send('Hello World!');
});

const port = process.env.PORT || 3000;
app.listen(port, () => {
  console.log(`App listening on port ${port}`);
});

Step 2: Building a Docker Image

Next, I needed to package this code into a container image that could be deployed and run on ECS.

I created a Dockerfile in the same directory and built the Docker image locally by running docker build -t deploying-simple-fargate-service . in the terminal.

# Dockerfile

FROM node:18-alpine
WORKDIR /usr/src/app
COPY package*.json ./
RUN npm install
COPY . .
EXPOSE 3000
CMD ["node", "index.js"]

Now, when I run docker images in the terminal, I can see the deploy-simple-fargate-service image.

Finally, I verified running the container image by running docker run -p 3000:3000 deploying-simple-fargate-service in the terminal. I confirmed it worked by visitinghttp://localhost:3000/ in a browser and seeing it return "Hello, World!".

Step 3: Pushing the Image to AWS ECR

With the container image ready, the next step is to upload it to AWS ECR, making it available for ECS to use.

I used the AWS Management Console to create a repository in AWS ECR named deploying-simple-fargate-service.

I confirmed that the image was successfully pushed.

Step 4: Creating the ECS Fargate Service

Finally, we can create the ECS Fargate Service.

To set up the ECS Fargate service, I started by creating a "Task Definition" called deploying-simple-fargate-service-task. In the Task Definition, I specified the ECR image URI (463601726399.dkr.ecr.us-east-1.amazonaws.com/deploying-simple-fargate-service:latest) and configured the container port to 3000. I left all the other settings as default.

Then, I created a "Cluster" called deploying-simple-fargate-service. I left all settings as default.

Within the Cluster, I created a "Service" called deploying-simple-fargate-service-service. I selected the Task Definition I had created earlier.

After a few minutes, the Service was created.

Step 5: Calling the Service

The last step is to call the Service. I clicked on the Service and selected the "Tasks" tab.

I clicked on the Task to open it, which displayed a public IP address.

I visited the following address: http://44.205.9.163:3000 on a browser and, sure enough, the "Hello World!" message appeared.