Install tzdata-legacy when building extra docker image

[TrayanZapryanov]

Describe the Problem

Once developers migrate from jammy:8.0 to runtime:9.0.0-noble-chiseled-extra, they can experience incompatibility issues with time zones.
Suggestion in 6072 was to install tzdata-legacy or to force ICU changing their stuff.

Describe the Solution

Install tzdata-legacy in extra image to prevent breaking changes.

Additional Context

See 6072 for more context.

[lbussell]

Thank you for the feature suggestion. The easy path for users being able to add tzdata-legacy to their own Chiseled images is going to depend on:

• Adding tzdata-legacy slice to https://github.com/canonical/chisel-releases
• Update Chisel to v1.0.0 #5973
• Need sample that shows the installation of additional packages in chiseled scenarios #4811

#4811 is the biggest unknown - if it turns out that adding packages to existing Chiseled images is still difficult/extra even after Chisel v1.0.0, then we could consider adding tzdata-legacy by default to noble extra images.

And just to be clear, @TrayanZapryanov, are you actually hitting this issue with Time Zone ID incompatibility today?

[TrayanZapryanov]

Yes,
Logs in previous issue were from production environment. At the moment they are not so much to rever to .net8 as only half of the customers are affected.

[mthalman]

• Adding tzdata-legacy slice to https://github.com/canonical/chisel-releases

I talked with @rebornplusplus about this. This is being investigated.

[richlander]

Do we have a size cost for tzdata-legacy? I am guessing it is a drop in the bucket compared to ICU.

[lbussell]

I went ahead and filed an issue to track this in the chisel-releases repo: Add tzdata-legacy slice for 24.04 (canonical/chisel-releases#405)

I'll get back to this issue with the maximum possible size increase by looking at the full package's installed size.

[lbussell]

Adding tzdata legacy to the image mcr.microsoft.com/dotnet/runtime-deps:9.0-noble-amd64 resulted in a compressed image size increase of 167 KB. This is not a chiseled image (because we don't have a slice readily available), but we should expect the size increase to be similar in magnitude when we add it to chiseled images. In my opinion, this size seems small enough that we could add it to all noble chiseled images without too much consideration.

For context, the current size of Chiseled base images today (compressed):

• mcr.microsoft.com/dotnet/runtime-deps:9.0-noble-chiseled-extra-amd64: 20.21 MB
• mcr.microsoft.com/dotnet/runtime:9.0-noble-chiseled-extra-amd64: 53.15 MB
• mcr.microsoft.com/dotnet/aspnet:9.0-noble-chiseled-extra-amd64: 63.93 MB

[lbussell]

[Triage] Looks like canonical/chisel-releases#405 is in-progress via canonical/chisel-releases#412. Since the installed size should be negligible, we will plan on adding this slice to all of our noble-chiseled images in a future .NET update - hopefully with the January servicing release.

[lbussell]

I validated that the newest images made a negligible difference in image size:

Image	Compressed Size Before	After
mcr.microsoft.com/dotnet/nightly/runtime-deps:9.0.0-noble-chiseled-extra-amd64	20.21 MB	20.35 MB
mcr.microsoft.com/dotnet/nightly/runtime:9.0.0-noble-chiseled-extra-amd64	53.15 MB	53.30 MB
mcr.microsoft.com/dotnet/nightly/aspnet:9.0.0-noble-chiseled-extra-amd64	63.93 MB	64.08

@TrayanZapryanov, are you able to validate that the latest nightly images, mcr.microsoft.com/dotnet/nightly/runtime:9.0.0-noble-chiseled-extra, fix your time zone issue with "FLE Standard Time"?

[TrayanZapryanov]

I will experiment tomorrow and will post results.