CI/CD for Legacy .NET Framework Apps: How to Automate Deployment Pipelines

Outdated deployment practices can slow down even the best software teams. When you’re still manually moving files between servers, it’s easy for small mistakes to slip through and updates to take longer than they should. At Keyhole Software, we’ve seen firsthand how this approach can hold back your projects. The solution is to automate deployment pipelines. It brings consistency, reliability, and speed to your release process.

Let’s explore how to replace outdated practices with a modern CI/CD pipeline for your legacy .NET Framework apps.

Why Automate Deployment Pipelines for Legacy .NET Framework Apps?

Automating deployment pipelines isn’t just about speed; it’s about reliability, security, and scalability. When you’re stuck in the old habit of manually copying and pasting code to different servers, small errors can slip in unnoticed, or critical updates can be missed altogether. Automating deployment pipelines allows you to build your app once and deploy it consistently across environments. No more guesswork or inconsistencies, just repeatable, predictable releases.

For many legacy .NET Framework applications, transitioning to an automated CI/CD pipeline might feel like a big leap. But with the right approach, you can start seeing immediate benefits in operational efficiency and cost savings.

Build Once, Deploy Many

One key practice in any CI/CD or DevSecOps environment is to build your code once and deploy it many times. This approach avoids issues that arise when you rebuild in different environments. We recommend using tools like Jenkins or Azure DevOps for legacy .NET Framework deployments. These tools can package your build as a single artifact, ensuring that the same version of your app is promoted from development to testing to production without any changes.

If you’re exploring modern containerization, building your application in a Docker image and deploying that container across environments is a smart move. Containers make it easier to maintain consistent environments and isolate dependencies.

Externalizing Configuration

In legacy deployments, configuration data is often baked into the codebase. This setup doesn’t work well when you’re automating deployment pipelines. Instead, you need to externalize configuration so it can be easily swapped out without touching the application’s core. This can be done with environment variables or, if you’re moving to Kubernetes, by mounting secrets.

For example, database connection strings or API keys should not be stored directly in the application code. By moving these settings to external configuration files or environment variables, you can maintain security and flexibility across deployments.

Managing Persistence and Storage

Legacy .NET Framework applications often store files or databases directly within the deployment environment. This setup becomes a hurdle in automated pipelines. Persistence must be separated from the application code.

At Keyhole Software, we guide clients to host databases and file storage independently from the app containers. This way, when you deploy or scale your app, you’re not duplicating large storage layers. It’s a foundational step in achieving reliable and cost-effective deployments.

Upgrading to .NET Core: A Path to Better Cost Efficiency

For new applications or those ready for a major overhaul, we recommend moving from .NET Framework to .NET Core. Microsoft has provided solid tools and documentation to help with this transition. Even so, we’ve seen that having experienced professionals involved in this upgrade is key to avoiding pitfalls.

.NET Core brings significant cost savings. Legacy apps usually run on Windows VMs, which are more expensive and less scalable. By moving to .NET Core, you can deploy to Linux containers that scale up and down as needed. At times of low usage, like overnight when no one is active, you aren’t paying for idle containers. This flexibility translates to lower infrastructure costs and faster deployments.

What We’ve Learned Helping Clients Automate Deployment Pipelines

Over the years, we’ve modernized countless .NET Framework applications and guided clients through upgrades to .NET Core. Here’s what we’ve seen firsthand:

• A strong build-once, deploy-many approach saves time and cuts down errors.
• Externalizing configuration ensures smoother deployments and easier environment transitions.
• Separating storage and databases from application code boosts scalability and simplifies backups.
• .NET Core container deployments on Linux consistently deliver better performance and lower costs.

Key Takeaways for Automating Deployment Pipelines

• Automate deployment pipelines to replace manual steps and increase reliability.
• Use a single build artifact for consistent deployments across all environments.
• Externalize configuration to make deployments secure and environment-agnostic.
• Consider .NET Core upgrades for cost efficiency and container-friendly deployments.
• Partner with experts to avoid common challenges and accelerate your modernization journey.

At Keyhole Software, we’re here to help you get started. We’ve seen how automating deployment pipelines can improve uptime, reduce errors, and future-proof your applications. Let’s talk about how we can take your legacy .NET Framework app to the next level, securely and cost-effectively.

Want to learn more about how we can help you automate deployment pipelines for your legacy applications? Contact us today and let’s get started.