Remove support for .NET 6.0

[MichaelSimons]

.NET 6.0 reached EOL on Nov 12, 2024. Per the Tag Lifecycle documentation, the 6.0 images will continue to be rebuilt upon base image updates for one month. After that time, all 6.0 infra, Dockerfiles, tests, documentation, etc. should be removed. Work can begin in nightly now.

[mthalman]

I was just going to log this. 😄

[lbussell]

Checklist:

• Remove all entries for the EOL .NET version in manifest.json, manifest.versions.json, ImageVersion.cs, TestData.cs, MCR tags metadata templates, and delete the Dockerfiles
• Search for and simplify conditions including the EOL .NET Version in the Dockerfile templates and tests
• Update the path variable appropriately for the dotnet-docker-nightly-pr-no-cache pipeline so that it continues to target active Dockerfiles.
• Replace all references to the EOL .NET version in documentation with a new .NET version
• Remove the EOL .NET version from the .NET Framework SDK images
  • https://github.com/microsoft/dotnet-framework-docker/blob/6a3c9d048f75c1e69c0e1059564cd56a90bf9e3c/eng/dockerfile-templates/sdk/Dockerfile#L56-L59
  • https://github.com/microsoft/dotnet-framework-docker/blob/58a18cf958883c6a67ae888854bd9bb09f085e83/eng/dockerfile-templates/sdk/Dockerfile.ltsc2016#L80-L81
• Post a new announcement on the GitHub Discussions page

[tri-bao]

unfortunately, we still need to stick with .net6 for awhile. Will .net6 docker images still exist in MCR after this ticket is done?

[richlander]

Yes. This issues is only about new images. There won't be any. We have no plans to delete any images.

EOL annotations are all you need worry about: #6054.

[MichaelSimons]

To re-enforce what @richlander stated. The following is documented in the Tag Lifecycle section of the Supported Tags documentation

When a .NET version reaches EOL, its tags will continue to be maintained (rebuilt for base image updates) until the next .NET servicing date (typically on "Patch Tuesday", the 2nd Tuesday of the month).

Once a tag is no longer maintained, it will be considered unsupported, and will no longer be updated. Unsupported tags will continue to exist in the container registry to prevent breaking any references to it.

[lbussell]

Per one of the checkboxes above, I updated the dotnet-docker-nightly-no-cache pipeline path args to:

- --path 'src/*/alpine*' --path 'src/*/6.0/nanoserver-ltsc2022/amd64' --path 'src/*/cbl-mariner*/amd64'
+ --path 'src/*/alpine*' --path 'src/*/9.0/nanoserver-ltsc2025/amd64' --path 'src/*/azurelinux*/amd64'