Migrating Legacy Applications to the Cloud: An AWS Case Study

The requirement for contemporary infrastructure is more and more important as businesses change. Older or on-premises systems are frequently the foundation of legacy apps, which can impede their capacity to grow, adapt, and innovate. These programs can be efficiently modernized, their performance can be increased, and their operating costs may be decreased with the help of cloud computing, especially when using services like Amazon Web Services (AWS). This blog will discuss the difficulties, steps involved, and advantages of cloud migration as we examine how one business moved its legacy apps to AWS.

The Client: A Global Financial Services Company

With decades of experience, the organization in this case study provides financial services globally. Older servers and databases were part of the legacy infrastructure that supported its core systems. The applications were essential for managing transactions, customer data, financial reporting, and day-to-day operations. But the outdated infrastructure resulted in expensive maintenance, regular outages, and the incapacity to grow during busy times.

The business came to the conclusion that updating its technological stack was necessary to stay competitive. They made the decision to move their old apps to the cloud, and because of AWS's extensive service portfolio, security features, and scalability, they selected the cloud provider.

Challenges Faced with Legacy Applications

Prior to the move, the business faced a number of significant obstacles:

• Limited Scalability: Performance bottlenecks occurred because the outdated on-premises infrastructure was unable to manage heavy traffic during peak hours.
• High Maintenance Costs: It got more and more expensive to maintain outdated software and hardware and needed a large workforce.
• Lack of Agility: Because its old applications were monolithic, the company found it difficult to develop fast and roll out new features.
• Compliance and Security Risks: The system was exposed to possible threats due to antiquated security mechanisms and a dearth of thorough monitoring tools.

Migration Strategy: Lift and Shift with AWS Services

Upon evaluating the organization's infrastructure and requirements, the migration team chose a staged lift-and-shift approach, utilizing AWS services to reduce downtime and guarantee a seamless transfer.

This is the course of the migration process:

1. Discovery and Assessment

The first step was to conduct a detailed assessment of the company’s existing applications and infrastructure. This involved:

• Application Analysis: Identifying the architecture, dependencies, and critical components of the legacy applications.
• Cost and Performance Evaluation: Estimating the cost of running these applications on AWS and identifying areas where performance improvements could be made.
• Risk Assessment: Understanding the potential risks of the migration, including data loss, downtime, and compliance issues.

AWS Migration Hub was used to centralize the discovery and tracking of the migration process. The team also used AWS Application Discovery Service to gather data on on-premises infrastructure and application dependencies.

2. Building a Cloud Architecture on AWS

After the assessment, the team designed a cloud architecture tailored to the company’s requirements. Key AWS services were selected to replace or augment the legacy components:

• Amazon EC2 (Elastic Compute Cloud): Virtual machines were used to host the migrated applications, ensuring the ability to scale up or down based on traffic demands.
• Amazon RDS (Relational Database Service): The company’s on-premises databases were migrated to RDS, offering managed database services with automated backups, patching, and scaling.
• Amazon S3 (Simple Storage Service): S3 was used to store unstructured data, such as reports and logs, with high durability and security.
• Amazon VPC (Virtual Private Cloud): A secure VPC was created to host the company’s applications, ensuring isolation and control over networking components.

3. Data Migration

Data migration was a critical step, as the company had vast amounts of sensitive customer and transaction data. The team used AWS Database Migration Service (DMS) to migrate databases with minimal downtime. AWS Snowball was also used to transfer large volumes of data securely and efficiently.

4. Testing and Validation

Before going live, the migrated applications were thoroughly tested in the AWS environment. The team conducted:

• Performance Testing: To ensure the applications performed better in the cloud environment compared to the legacy infrastructure.
• Security Testing: To validate that the applications met the required security and compliance standards, leveraging AWS Identity and Access Management (IAM) and AWS Shield for additional protection.
• Disaster Recovery Testing: Using Amazon Route 53 and AWS CloudFormation, a disaster recovery plan was put in place to ensure business continuity in case of any failures.

5. Final Cutover and Optimization

After successful testing, the company executed the final cutover, moving the production environment to AWS. The team used AWS Elastic Load Balancing (ELB) to distribute traffic across multiple instances and ensure high availability.

Following the migration, the team focused on optimizing the environment by:

• Auto-scaling: Configuring Auto Scaling Groups to ensure resources automatically adjust to traffic demands, reducing costs during low traffic periods.
• Cost Optimization: Utilizing AWS Cost Explorer and AWS Trusted Advisor to monitor usage and optimize resource allocation.

Post-Migration Benefits

After migrating its legacy applications to AWS, the company experienced significant improvements in several areas:

1. Improved Performance and Scalability: The applications could now automatically scale to handle increased traffic, improving response times during peak periods.
2. Reduced Costs: By using AWS’s pay-as-you-go pricing model and optimizing resources with auto-scaling, the company significantly reduced its operational costs compared to maintaining on-premises infrastructure.
3. Increased Agility: AWS enabled the company to deploy new features faster, as development teams could take advantage of services like AWS Lambda and Amazon ECS (Elastic Container Service) for building and deploying applications in a more agile environment.
4. Enhanced Security and Compliance: AWS’s built-in security services and compliance certifications provided the company with a more robust security posture. Services like AWS CloudTrail and AWS Config allowed the company to continuously monitor compliance and security configurations.
5. Disaster Recovery and Business Continuity: With AWS’s global infrastructure and backup solutions, the company now had a reliable disaster recovery plan in place, reducing the risk of data loss or extended downtime.

Lessons Learned

While the migration was successful, several key lessons emerged:

• Plan for Complexity: Migrating legacy applications can be complex, particularly when dealing with older systems that have deeply integrated dependencies. A detailed discovery and assessment phase is essential to avoid unexpected issues during migration.
• Phased Approach: Using a phased migration strategy reduced the risk of downtime and allowed for easier troubleshooting at each step.
• Security is Paramount: Leveraging AWS’s security tools and services is critical, especially when migrating sensitive data. Ensuring compliance with industry regulations should be a priority from the start.

Conclusion

Although moving old apps to the cloud might be difficult, there are a lot of advantages in terms of performance, cost savings, and agility when you have the correct plan and resources in place. Organizations may more easily upgrade their infrastructure and grow their applications with the help of AWS's extensive suite of services.