An Architecture for a highly available and web application with best practices

Designing a highly available and scalable architecture for a web application that needs to support millions of users globally requires a combination of AWS services and best practices.

Here's a high-level overview of a possible architecture:

Content Delivery: Use Amazon CloudFront to deliver content globally with low latency and high throughput. You can also use Amazon S3 to store and serve static content.

Compute: Use Amazon EC2 Auto Scaling to automatically scale your compute resources based on traffic patterns. You can also use AWS Lambda to handle serverless workloads and AWS Fargate to manage containerized workloads.

Database: Use Amazon RDS or Amazon DynamoDB to store and manage your data. You can also use Amazon ElastiCache to cache frequently accessed data and reduce database load.

Networking: Use Amazon Route 53 to route traffic to the nearest AWS region and reduce latency. You can also use Elastic Load Balancing to distribute traffic across multiple instances and availability zones.

Security: Use AWS Identity and Access Management (IAM) to manage access to your resources. You can also use AWS WAF and AWS Shield to protect against DDoS attacks.

Monitoring: Use Amazon CloudWatch to monitor your application and infrastructure. You can also use AWS X-Ray to trace requests and diagnose issues.

To handle sudden spikes in traffic, you can configure EC2 Auto Scaling to automatically add and remove instances based on metrics such as CPU utilization or network traffic. You can also use CloudFront to cache frequently accessed content and reduce load on your origin servers.

By following AWS best practices, such as using multiple availability zones, configuring backups and disaster recovery, and regularly testing your architecture, you can ensure high availability and scalability for your web application.