Module 17: DevOps & Deployment

This final module marks the transition from “writing code” to “running a product.” DevOps is the culture and practice of unifying software development (Dev) and software operation (Ops). In modern .NET, this almost always involves automation and cloud environments.

1. Build & Publish Process

Before code can run on a server, it must be compiled and packaged.

• The “Build” Step: The compiler checks for syntax errors and turns .cs files into .dll (Dynamic Link Libraries).
• The “Publish” Step: This is a specific .NET command (dotnet publish) that gathers everything your app needs to run—DLLs, configurations, and dependencies—into a single folder.
• Self-Contained vs. Framework-Dependent: You can publish an app that includes the .NET runtime (Self-contained) so the server doesn’t even need .NET installed to run it.

2. IIS (Internet Information Services) Deployment

For many years, IIS was the only way to host .NET apps on Windows.

• How it works: IIS acts as a “Reverse Proxy.” It receives requests from the internet (Port 80/443) and passes them to your .NET application.
• App Pools: IIS isolates applications into “Application Pools,” ensuring that if one website crashes, it doesn’t take down the others on the same server.

3. Docker Basics for .NET

Docker has revolutionized deployment by allowing you to “package” your app with its exact environment.

• The Container: Instead of saying “It works on my machine,” you send the “Machine” (the container) to the server.
• Dockerfile: A text file containing instructions to build your image.
  • Example: “Start with the .NET 8 Runtime image, copy my files, and run dotnet MyApi.dll.”
• Benefits: Consistency across Dev, Staging, and Production. No more “missing DLL” errors on the server.

4. CI/CD Pipeline Overview

CI/CD removes the human element (and human error) from deployment.

• Continuous Integration (CI): Every time you “Push” code to GitHub/GitLab, a server automatically builds the code and runs all your Module 16 tests. If a test fails, the code is rejected.
• Continuous Deployment (CD): If the CI passes, the server automatically “deploys” the code to the hosting environment (Azure, AWS, or IIS).

5. Cloud Intro (Azure Preferred)

As a .NET developer, Microsoft Azure is your “home court.” It offers specialized services for .NET:

• Azure App Service: The easiest way to host web apps. You just push your code, and Azure handles the scaling and patching.
• Azure SQL Database: A managed version of SQL Server. No need to manage the Windows Server; you just manage the data.
• Azure Functions: “Serverless” code. You write a single function that runs only when triggered (e.g., when a user uploads a photo).

6. From Local to Live: The Real-World Workflow

1. Develop: Write code in Visual Studio/VS Code.
2. Commit: Push code to a Git repository (GitHub/Azure DevOps).
3. Build (CI): A pipeline pulls the code, runs dotnet build and dotnet test.
4. Package: The pipeline creates a Docker Image.
5. Deploy (CD): The pipeline pushes the Docker image to Azure App Service.
6. Monitor: You use Application Insights to watch for errors (Module 15).

🎯 Outcome: Launch Your Application

By finishing this final module, you have completed the journey of a Software Engineer. You now know how to:

1. Prepare a .NET app for the real world.
2. Containerize applications using Docker.
3. Automate the “Release” process so you can deploy with a single click.
4. Navigate the Azure portal to host and manage live websites.