Proposal: New tagging pattern for .NET 8 previews

[mthalman]

New tagging pattern for .NET 8 previews

Problem Description

The .NET tagging pattern has historically used a floating major/minor version tag (e.g. 7.0) for each release, starting with preview releases. We'll focus on .NET 7 as the basis for discussion here. With the release of .NET 7 Preview 1 we published 7.0 and 7.0.0-preview.1 tags. Customers were free to use the floating 7.0 tag to move along with each preview or explicitly transition between each preview release by using the tag specific to the preview number (e.g. 7.0.0-preview.1).

The intent with this pattern was to allow early adopters to start using the new features of preview releases and seamlessly transition to supported releases once the version had its GA release. The floating 7.0 tag would give you the latest preview versions as they were being released and then transition to supported servicing releases after GA of .NET 7.

This has lead to some confusion because the 7.0 tag doesn't indicate its supported state at all (see #3531). It has caused some automation tools that to mistakenly think your Dockerfile isn't referencing the latest version of .NET if it's referencing a 6.0 tag (currently the latest supported release). We'd like to avoid this confusion in our tagging pattern.

Proposal

Beginning with .NET 8, the .NET container images will adopt a new tagging pattern that helps to indicate the supported state of the tag. The primary difference from the tagging pattern used historically is that a floating 8.0 won't be introduced until later in the release cycle. Instead, a floating 8.0-preview tag will be used. The tagging pattern maps to the timeline of the .NET 8 release cycle, shown below. For purposes of brevity, tags specific to patch versions and OS (e.g. 8.0.0-preview, 8.0-preview-alpine) aren't shown here.

Release	New Tags	Updated Tags
.NET 8 Preview 1	8.0-preview 8.0.0-preview.1	n/a
.NET 8 Preview N (where N > 1)	8.0.0-preview.N	8.0-preview
.NET 8 RC 1	8.0 8.0.0-rc.1	n/a
.NET 8 RC N (where N > 1)	8.0.0-rc.N	8.0
.NET 8 GA	n/a	8.0

With each preview release, the 8.0-preview tag will be updated to reference the latest preview image. That will continue until the first RC release. At that point, the 8.0 tag will be introduced and maintenance of the 8.0-preview tag will be discontinued. Since the RC release will be supported for production use, the intent here is to make this transition now, ahead of the GA release, to provide a smooth experience starting from now, through GA, and into servicing.

We believe this tagging pattern is a good compromise that allows tag changes to be made well ahead of the GA release and yet doesn't mislead people into thinking a .NET version is ready for production use when it's still in preview.

[busches]

Greatly improved and mirrors other projects. 👍

[JamieMagee]

My only question is: should .NET 8 RCs be tagged with the 8.0 tag? I would expect 8.0 to be reserved for GA releases.

That being said, I understand the desire to get early feedback. If you're happy with automation tools proposing upgrading from 7.0 to 8.0 when 8.0 is at the RC stage, then this sounds great.

[mthalman]

My only question is: should .NET 8 RCs be tagged with the 8.0 tag? I would expect 8.0 to be reserved for GA releases.

Given that .NET RCs have a "go live" license, meaning they are supported for production use, our assertion is that it is appropriate to make them available with the 8.0 tag.

[JamieMagee]

Thanks for the clarification, and thanks for putting this proposal together. This all sounds great!

[mthalman]

This pattern is now implemented in the nightly branch via #4204. It will be in effect upon the official release of .NET 8 Preview 1 images.