Upgrade docker image BaseImage from powershell to dotnet/sdk

[YanaXu]

Description

Mandatory Checklist

• Please choose the target release of Azure PowerShell. (⚠️Target release is a different concept from API readiness. Please click below links for details.)

  • General release
  • Public preview
  • Private preview
  • Engineering build
  • No need for a release

• Check this box to confirm: I have read the Submitting Changes section of CONTRIBUTING.md and reviewed the following information:

• SHOULD update ChangeLog.md file(s) appropriately
  • Update src/{{SERVICE}}/{{SERVICE}}/ChangeLog.md.
    • A snippet outlining the change(s) made in the PR should be written under the ## Upcoming Release header in the past tense.
  • Should not change ChangeLog.md if no new release is required, such as fixing test case only.
• SHOULD regenerate markdown help files if there is cmdlet API change. Instruction
• SHOULD have proper test coverage for changes in pull request.
• SHOULD NOT adjust version of module manually in pull request

[azure-client-tools-bot-prd]

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[YanaXu]

/azp run

[Copilot]

Pull Request Overview

This PR upgrades the Docker base images from PowerShell-specific images to .NET SDK 9.0 images across all Dockerfile variants. This change aligns with moving to a .NET SDK-based build environment while maintaining support for PowerShell functionality.

Key changes:

• Replaced PowerShell base images with .NET SDK 9.0 equivalents across all platforms
• Updated package manager commands to match the new base image distributions
• Removed two legacy Dockerfile variants (Ubuntu 22.04 and UBI-9)

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
docker/Dockerfile-ubuntu-24.04	Updated base image from PowerShell Ubuntu 24.04 to .NET SDK 9.0 Noble
docker/Dockerfile-ubuntu-22.04	Removed entire Ubuntu 22.04 Dockerfile variant
docker/Dockerfile-ubi-9	Removed entire UBI-9 Dockerfile variant
docker/Dockerfile-debian-12	Updated base image from PowerShell Debian 12 to .NET SDK 9.0 Bookworm Slim
docker/Dockerfile-azurelinux-3.0-arm64	Updated base image and added tar/gzip packages, fixed environment variable
docker/Dockerfile-azurelinux-3.0	Updated base image and added tar/gzip packages
docker/Dockerfile-alpine-3.22	Updated base image and package manager commands from yum to apk, corrected image names
docker/Dockerfile-alpine-3.21	Updated base image and corrected image/environment variable names

[Copilot]

The original file was based on UBI-8 (using yum commands) but the new Alpine base image uses apk. However, the package manager command change from yum update -y && yum clean all to apk update && apk upgrade --no-cache is correct, but the filename suggests this should be Alpine 3.22 while the original was UBI-8. This appears to be a mismatch between filename and original content.

[Copilot]

The original base image was mcr.microsoft.com/powershell:alpine-3.20 but the new image uses Alpine 3.21. This version change should be intentional - verify that Alpine 3.21 is the correct target version and not Alpine 3.20.

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[VeryEarly]

azure-powershell is targeting dotnet 8 right now, can you please make the base images dotnet 8 instead of dotnet 9?