Add support for Server 2025

[MichaelSimons]

New Windows Release

Windows version: Server 2025

Related to dotnet/core#9374

Main Branch Tasks

1. • Ensure a "New Windows Release" issue exists for docker-tools repo
2. • Copy the Dockerfiles of the most recent published Windows version for all supported .NET versions and place them in a version-specific folder under their respective variants (runtime, aspnet, sdk)
3. • Modify the Dockerfile templates if there are any specific changes needed that are related to the new Windows version
4. • Update manifest.json to reference the new set of Dockerfiles with the appropriate tags
5. • Update the test data to include the new Windows version
6. • Update the tags metadata templates to include the new Windows version
7. • Run the command to update the READMEs: .\eng\readme-templates\Get-GeneratedReadmes.ps1
8. • Run the command to update the image size baseline file: .\tests\performance\Validate-ImageSize.ps1 -UpdateBaselines
9. • Inspect generated changes for correctness
10. • Test the images
      1. • Create a local VM of the new Windows version
      2. • Clone this repo with the above changes onto the VM
      3. • Run .\build-and-test.ps1 -OS nanoserver-<VERSION> to build and test your changes for Nano Server
      4. • Run .\build-and-test.ps1 -OS windowsservercore-<VERSION> to build and test your changes for Windows Server Core
11. • Create PR
12. • Get PR signoff
13. • Merge PR and build/publish as part of the main branch release process for the next .NET release
14. • Create an announcement (example: Nano Server, version 20H2)
15. • Update the samples to reference the new Windows version:
      • Nano Server and Windows Server Core sample Dockerfiles
      • manifest.samples.json

Nightly Branch Tasks

• Merge these changes to the nightly branch as part of the nightly branch release process for the next .NET release.

[lbussell]

[Triage] Related: microsoft/dotnet-framework-docker#1146

[lbussell]

[Triage] This is blocked on dotnet/dnceng#3781.

[lbussell]

We now have some Server 2025 pools and VM images available. This is now blocked on dotnet/docker-tools#1453.

[amitie10g]

Since base container images for ltsc2025 are available, are the .NET images suitable for been deployed now?

[lbussell]

@amitie10g, Preview LTSC 2025 .NET images are available in the nightly repos, so you can try them out now. We are waiting on additional validation from the .NET Runtime before we publish the images as officially supported (dotnet/core#9374).