AWS lesson

AWS Elastic Beanstalk With Use Cases

AWS Elastic Beanstalk is a fully managed service that makes it easy to deploy, run, and scale web applications and services. You provide your code, and Beanstalk handles provisioning and managing the infrastructure: EC2 instances, load balancers, auto scaling, health monitoring, and application deployment.

Elastic Beanstalk Key points

Supported platforms: Java, .NET, Node.js, Python, Ruby, PHP, Go, Docker, and more.
Deployment models: Single instance, Load balanced + Auto Scaling, Worker environments (for background jobs via SQS).
Configuration: Use configuration files (.ebextensions, platform hooks) and environment variables.
Monitoring: Built-in health checks, logs, and metrics via CloudWatch.
Rolling updates and blue/green deployments supported.

Example scenario: Deploy a Node.js web app

Goal: Deploy a simple Node.js Express app behind an Application Load Balancer with automatic scaling.

Prepare your app

App structure:
- package.json (specifies start script)
- app.js (Express server listening on process.env.PORT)

Example app.js:

const express = require('express');
const app = express();
const port = process.env.PORT || 8080;
app.get('/', (req, res) => res.send('Hello from Elastic Beanstalk!'));
app.listen(port, () => console.log(`Server listening on ${port}`));

Example package.json:

{
"name": "eb-node-demo",
"version": "1.0.0",
"main": "app.js",
"scripts": { "start": "node app.js" },
"dependencies": { "express": "^4.18.2" }
}

Initialize Beanstalk (CLI)

Install AWS EB CLI: pip install awsebcli
Initialize the app:

eb init
# Choose region, platform (Node.js), and set up SSH key if desired

Create an environment and deploy

eb create eb-node-env \
  --single   # or omit --single to create a load-balanced, auto-scaling environment
# Wait until environment is ready
eb deploy

Access your app

eb open

This opens the environment URL like http://eb-node-env.us-east-1.elasticbeanstalk.com

Configure scaling and variables

To run with a load balancer and auto scaling, create without --single:

#bash
eb create eb-node-prod

Set environment variables:

#bash
eb setenv NODE_ENV=production API_BASE_URL=https://api.example.com

Basic .ebextensions (optional)
Add .ebextensions/options.config to set instance type and health check path:

#yaml
option_settings:
    aws:autoscaling:launchconfiguration:
        InstanceType: t3.small
    aws:elasticbeanstalk:application:
        Application Healthcheck URL: /health

Blue/Green deployment (high level)

Create a second environment (green), deploy and test there.
Swap CNAMEs between green and blue environments from the console or:

#bash
eb swap --source eb-node-blue --destination eb-node-green

Typical use cases

Quickly deploying web apps without managing infrastructure.
Teams that want opinionated defaults for ALB, Auto Scaling, logs, and health checks.
Worker environments for background processing with SQS.

When to choose Beanstalk

You want managed infrastructure with minimal ops, but more control than pure serverless.
You prefer pushing code over writing IaC for all components.
You need rolling updates, health checks, and auto scaling out-of-the-box.

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