Migrating an Enterprise Application to AWS

Migrating an Enterprise Application to AWS: A Strategic Approach

In today’s digital era, businesses must scale, innovate, and optimize their infrastructure for better performance and cost efficiency. Cloud migration has become a key step for enterprises looking to enhance agility and reduce operational overhead. This blog explores a real-world migration journey of a regional SaaS provider to AWS, highlighting the challenges, strategies, and solutions implemented for a seamless transition.

Understanding the Business Context

A regional enterprise aiming for global expansion sought to modernize its infrastructure. Their focus was on digitizing customer interactions, enhancing online sales, and improving customer service through digital channels. However, their on-premises setup struggled with increasing traffic, leading to performance issues and limited scalability.

The company decided to migrate its online customer portal to AWS. This portal, a monolithic Java application using Spring and Hibernate, was deployed on WebSphere Application Server with an Oracle database. During migration, it was crucial to maintain integrations with key on-premises services like:

• Billing System (via IBM Message Queue)

• Rewards Platform (via SOAP APIs)

• Payments Gateway (via Java RMI with direct bank connections)

Additionally, the portal handled extensive text-based and identifier-based searches, processing over one million requests per day.

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Staggered Migration Approach

A staggered migration approach was chosen to minimize risk, reduce downtime, and ensure business continuity. The process involved multiple phases:

1. Assessment & Planning:

   • Conducted a detailed application dependency analysis.

   • Identified key integrations, data pipelines, and high-risk areas.

   • Defined a roadmap with phased workloads to migrate.

2. Proof of Concept (PoC) & Testing:

   • Deployed a pilot migration of non-critical services.

   • Validated performance, security, and network configurations.

   • Tested rollback mechanisms for contingency planning.

3. Incremental Migration:

   • Migrated independent microservices first, reducing complexity.

   • Lift-and-shift for low-risk applications, re-platform for performance-critical components.

   • Parallel-run of key systems to validate real-time data consistency.

4. Final Cutover & Optimization:

   • Switched traffic gradually using weighted DNS routing.

   • Monitored system behavior post-migration.

   • Optimized cloud resources based on real-world performance data.

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Database Migration Strategies

Migrating a monolithic database required careful planning to ensure data integrity and minimize downtime. The following strategies were evaluated:

1. One-shot Migration:

   • Bulk data export/import using AWS Snowball or AWS DMS.

   • Suitable for applications with minimal data change frequency.

   • Requires downtime, best for off-peak hours.

2. Parallel Migration:

   • Live database runs on both on-premises and AWS concurrently.

   • AWS Database Migration Service (DMS) used for real-time replication.

   • Allows phased transition, reducing operational risk.

3. Hybrid Migration (Phased Approach):

   • Initial bulk migration using AWS SCT and DMS.

   • Continuous Change Data Capture (CDC) until cutover.

   • Ensures zero downtime for critical applications.

4. Blue-Green Deployment for Databases:

   • Maintains two environments (old and new) in parallel.

   • Switches over once AWS-based database is fully validated.

   • Ensures seamless transition with rollback capability.

AWS Aurora was chosen due to its auto-scaling capabilities, high availability, and compatibility with MySQL/PostgreSQL.

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Proposed Solution Architecture

The migration strategy revolved around four key pillars:

Application Modernization & Deployment

1. 

2. Network & Security Design

   

   3. DevOps & Automation Strategy

1. Application Modernization & Deployment

• API Management:

  • Used Network Load Balancer (NLB) for private subnet communication.

  • Adopted an API Gateway → VPC Link → ALB → APIs approach for HTTP services.

• Authentication & Security:

  • Implemented AWS Cognito, Amplify, and IAM profiles for authentication.

  • Enabled OAuth2/OpenID Connect-based authentication for enhanced security.

• Data Streaming & Search Optimization:

  • Integrated ElastiCache & Elasticsearch for real-time data synchronization and fast retrieval.

  • Leveraged Kafka-driven data pipelines for efficient processing.

  • Utilized AppSync GraphQL APIs to optimize search services and provide unified data access.

2. Security & Compliance Considerations

• Identity & Access Management:

  • Enforced RBAC (Role-Based Access Control) using IAM policies.

  • Integrated AWS Cognito with SSO (Single Sign-On).

• Threat Protection:

  • Used AWS Shield Advanced for DDoS mitigation.

  • Implemented WAF rules to block malicious web traffic.

• Regulatory Compliance:

  • Ensured GDPR, PCI-DSS, and ISO 27001 compliance through AWS security frameworks.

  • Enabled AWS Macie for automated PII detection.

3. DevOps & Automation Strategy

• Containerization & Orchestration:

  • Migrated applications to Amazon EKS (Kubernetes).

  • Evaluated AWS Fargate for serverless container management.

• Infrastructure as Code (IaC):

  • Used Terraform for cross-cloud infrastructure automation.

  • Leveraged AWS CloudFormation for AWS-native resource provisioning.

• Monitoring & Logging:

  • Deployed Prometheus and Grafana for real-time observability.

  • Integrated AWS CloudWatch for system-wide monitoring.

4. Microservices and Cloud Adoption

• Strangler Fig Approach for Monolith Decomposition:

  • Gradually replaced monolithic components with microservices.

  • Ensured backward compatibility using API gateways.

• Event-Driven Architecture:

  • Used Amazon EventBridge & Kafka for asynchronous communication.

  • Implemented SQS & SNS for event-driven messaging.

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Disaster Recovery (DR) Strategy

• Active-Passive Model:

  • Used Aurora DB replication across AWS regions.

• Backup & Recovery:

  • Scheduled AWS Backup for periodic snapshots.

  • Enabled automated failover with AWS Route 53 Health Checks.

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Key Takeaways

1. Incremental migration with staggered phases minimized business disruptions.

2. Hybrid database migration approach ensured data consistency and zero downtime.

3. PaaS-first adoption reduced maintenance overhead and improved scalability.

4. Microservices strategy enabled long-term cloud agility and API-first development.

5. Comprehensive security controls ensured compliance with financial regulations.

6. Disaster recovery and high availability strategy enhanced system resilience.

By strategically migrating to AWS, the company resolved its performance challenges and laid the foundation for scalable, agile, and innovation-driven growth. If you’re considering a cloud migration journey, AWS offers the tools and infrastructure to support a seamless transition.