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AWS Highly Available Web Application

An architecture design and implementation plan for a resilient, auto-scaling AWS web application — covering networking, compute, database failover, and monitoring.

AWSVPCEC2ALBAuto ScalingRDSCloudWatch
Architecture Design

Project Overview

This is a reference architecture I designed for a resilient, multi-tier AWS web application — the same pattern I'd apply when a client needs an application that stays online through instance failures, Availability Zone outages, and traffic spikes. It separates public traffic, application servers, and database resources, and layers in load balancing, auto-scaling, and monitoring around each tier.

Architecture

Internet │ ▼ Application Load Balancer │ ├───────────────┐ ▼ ▼ EC2 / App #1 EC2 / App #2 │ │ └───────┬───────┘ ▼ Amazon RDS (private subnet) CloudWatch monitors EC2, ALB and application metrics.

Implementation Approach

  1. Create a VPC with public and private subnets across multiple Availability Zones.
  2. Place the Application Load Balancer in public subnets and application servers in private or controlled subnets.
  3. Configure EC2 launch templates and an Auto Scaling Group for repeatable application instances.
  4. Use RDS Multi-AZ in private subnets with security groups allowing only required application traffic.
  5. Apply IAM roles, security groups, least-privilege access, and encrypted connections where appropriate.
  6. Configure CloudWatch monitoring, alarms, logs, and operational dashboards.