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Building a Scalable and Secure Web Application on AWS: A Step-by-Step Guide

Building a Scalable and Secure Web Application on AWS: A Step-by-Step Guide

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Swapna Aware
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4 min read

In today's cloud-driven landscape, it's essential to ensure that your web application is scalable, highly available, and secure. AWS offers a variety of services such as EC2, launch templates, load balancers, auto-scaling, and WAF, which simplify the process of building a strong infrastructure. In this blog, we'll guide you through the setup and configuration of these important AWS components, complete with a live example and a straightforward diagram.

Key AWS Components Overview

1) AWS EC2 (Elastic Compute Cloud) offers flexible computing power in the cloud. It enables you to operate virtual servers that can easily scale up or down based on your requirements.

  • Benefits:

    • Flexible configurations.

    • Scalable to meet traffic demands.

    • Cost-efficient: Pay only for what you use.

2) Launch Templates: Predefined templates that store EC2 instance configurations, making it easier to launch instances with consistent settings.

3) Load Balancers: Distributes incoming traffic across multiple EC2 instances to ensure application availability and prevent overload.

Types:

  • Application Load Balancer (ALB): For routing based on HTTP/HTTPS traffic.

  • Network Load Balancer (NLB): Handles high-performance TCP/UDP traffic.

  • Benefits:

    • High availability and fault tolerance.

    • Prevents traffic overload on a single instance.

4) Auto Scaling: Automatically adds or removes EC2 instances based on traffic demand or specified policies.

  • Types of Scaling:

    • Dynamic Scaling: Adds/removes instances based on real-time demand.

    • Scheduled Scaling: Launches instances at predetermined times based on expected load.

  • Benefits:

    • Ensures optimal instance usage during high or low traffic.

    • Provides fault tolerance by replacing unhealthy instances.

5) AWS WAF (Web Application Firewall):: Protects your application from common web vulnerabilities like SQL injection and cross-site scripting (XSS).

  • Benefits:

    • Filters malicious traffic.

    • Customizable rules for security.

    • Seamless integration with Application Load Balancers.

Live Example: Setting Up EC2, Launch Templates, Load Balancers, Auto Scaling, and WAF

Step 1: Launch an EC2 Instance

  1. Log in to AWS Management Console and navigate to EC2.

  2. Click Launch Instance and select Amazon Linux 2 AMI.

  3. Choose an instance type (e.g., t2.micro for free tier) and configure instance details.

  4. Add a User Data Script to install Apache when the instance starts:

     #!/bin/bash
 sudo yum update -y
 sudo yum install httpd -y
 sudo systemctl start httpd
 sudo systemctl enable httpd

  5. Launch the instance.

Step 2: Create a Launch Template

  1. In the EC2 Dashboard, select Launch Templates and click Create Launch Template.

  2. Provide a name for the template and configure it with the AMI, instance type, security groups, and User Data Script (from Step 1).

  3. Save the launch template for future use in Auto Scaling.

Step 3: Configure a Load Balancer

  1. In the EC2 Dashboard, navigate to Load Balancers and click Create Load Balancer.

  2. Choose Application Load Balancer.

  3. Set up listeners to forward HTTP (Port 80) traffic and assign the load balancer to appropriate VPC and subnets.

  4. Create a Target Group that points to the EC2 instances created from the launch template.

Step 4: Set Up Auto Scaling

  1. In the EC2 Dashboard, go to Auto Scaling Groups and click Create Auto Scaling Group.

  2. Select the Launch Template created in Step 2.

  3. Set a Desired Capacity (e.g., 2 instances), Minimum, and Maximum Instances.

  4. Configure scaling policies:

    • Target Tracking: Add instances when CPU usage exceeds 70%.

    • Scheduled Scaling: Automatically scale up during high traffic hours.

Step 5: Enable AWS WAF

  1. In the AWS Console, go to WAF & Shield.

  2. Click Create Web ACL and choose Application Load Balancer as the resource to protect.

  3. Add rules to filter common web attacks like SQL injection and XSS.

  4. Attach WAF to the load balancer for enhanced security.

How It Works:

  1. WAF filters malicious traffic before it reaches the load balancer.

  2. The Load Balancer distributes traffic to EC2 instances in different availability zones.

  3. Auto Scaling automatically adjusts the number of instances based on demand, ensuring cost efficiency and availability.

Conclusion

By using AWS EC2, launch templates, load balancers, auto-scaling, and WAF, you can build a web application that is not only scalable and highly available but also secure. These components work together to handle fluctuating traffic, distribute loads evenly, and protect your application from cyber threats. This setup ensures that your web applications are ready to handle any challenges while keeping costs in check.