Legacy .NET Application Cloud Migration
Migrated a .NET Framework 4.5 on-premises application to Azure, achieving 99.9% uptime, 60% cost savings, and zero security findings — in a phased 6-month engagement.
99.9%
Uptime (was 96.5%)
60%
Infrastructure Cost Reduction
15 min
Deploy Time (was 2 weeks)
The Challenge
A financial services company was running a critical .NET Framework 4.5 application on ageing on-premises hardware. The application had accumulated over a decade of technical debt, and the infrastructure was consistently failing security audits. Patching the server environment was increasingly risky given the age of the application's dependencies.
The system had no automated deployment pipeline — releases required a full weekend of manual steps and rollback procedures, averaging two weeks from development to production. Scaling was impossible without expensive hardware procurement, and peak load events regularly pushed the servers to their limits.
The business needed to modernise without disrupting the application's core function. A complete rewrite was out of scope, but simply moving the application as-is would not resolve the security findings or unlock the scalability and cost benefits of cloud infrastructure.
The Solution
We executed a phased migration strategy. Phase one was lift-and-shift: containerise the existing application using Docker, resolve all dependency and configuration issues, and deploy to Azure App Service. This phase resolved the security audit findings and eliminated the on-premises hardware costs within 6 weeks.
Phase two was re-architecture. With the application running stably in Azure, we incrementally extracted high-traffic components into .NET 8 microservices deployed to Azure Kubernetes Service. Each service was backed by Azure SQL, with Azure Key Vault managing all secrets. A GitHub Actions CI/CD pipeline replaced the manual deployment process entirely.
The final state was a microservices platform with horizontal auto-scaling, blue-green deployment capability, and full observability through Azure Monitor. Deployment time dropped from two weeks to 15 minutes. The AKS cluster right-sized compute requirements, cutting infrastructure spend by 60% compared to the on-premises footprint.
Architecture Overview
Technologies Used
The Results
99.9%
Uptime (was 96.5%)
60%
Infrastructure Cost Reduction
15 min
Deploy Time (was 2 weeks)