This pattern describes the steps for modernizing a legacy, monolith ASP.NET Web Forms application by porting it to ASP.NET Core on AWS.
Porting ASP.NET Web Forms applications to ASP.NET Core helps you take advantage of the performance, cost savings, and robust ecosystem of Linux. However, it can be a significant manual effort. In this pattern, the legacy application is modernized incrementally by using a phased approach, and then containerized in the AWS Cloud.
Consider a legacy, monolith application for a shopping cart. Let’s assume that it was created as an ASP.NET Web Forms application and consists of .aspx pages with a code-behind (aspx.cs) file. The modernization process consists of these steps:
Break the monolith into microservices by using the appropriate decomposition patterns. For more information, see the guide Decomposing monoliths into microservices on the AWS Prescriptive Guidance website.
Port your legacy ASP.NET Web Forms (.NET Framework) application to ASP.NET Core in .NET 5 or later. In this pattern, you use Porting Assistant for .NET to scan your ASP.NET Web Forms application and identify incompatibilities with ASP.NET Core. This reduces the manual porting effort.
Redevelop the Web Forms UI layer by using React. This pattern doesn’t cover UI redevelopment. For instructions, see Create a New React App in the React documentation.
Redevelop the Web Forms code-behind file (business interface) as an ASP.NET Core web API. This pattern uses NDepend reports to help identify required files and dependencies.
Upgrade shared/common projects, such as Business Logic and Data Access, in your legacy application to .NET 5 or later by using Porting Assistant for .NET.
Add AWS services to complement your application. For example, you can use Amazon CloudWatch Logs to monitor, store, and access your application’s logs, and AWS Systems Manager to store your application settings.
Containerize the modernized ASP.NET Core application. This pattern creates a Docker file that targets Linux in Visual Studio and uses Docker Desktop to test it locally. This step assumes that your legacy application is already running on an on-premises or Amazon Elastic Compute Cloud (Amazon EC2) Windows instance. For more information, see the pattern Run an ASP.NET Core web API Docker container on an Amazon EC2 Linux instance.
Deploy the modernized ASP.NET core application to Amazon Elastic Container Service (Amazon ECS). This pattern doesn’t cover the deployment step. For instructions, see the Amazon ECS Workshop.
