Move helix-platforms.yml ARM host VMs from Ubuntu 22.04 to Azure Linux 3

[richlander]

Note

This PR was AI/Copilot-generated (Copilot CLI v1.0.11).

Move all ARM container host VMs in helix-platforms.yml from Ubuntu 22.04 to Azure Linux 3:

• Ubuntu.2204.ArmArch.Open → AzureLinux.3.Arm64.Open
• Ubuntu.2204.ArmArch → AzureLinux.3.Arm64

Only the host VM that runs the containers is changed. The container images (test OS) are unchanged:

• ARM32: Debian 13, Alpine 3.23
• ARM64: Ubuntu 26.04, Ubuntu 22.04 (oldest-supported), Alpine 3.23

AzureLinux.3.Arm64 is already used as the ARM host VM in both libraries/helix-queues-setup.yml and coreclr/templates/helix-queues-setup.yml, so this aligns helix-platforms.yml with existing practice.

13 host VM replacements across ARM32 (glibc + musl) and ARM64 (musl) sections.

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[Copilot]

Pull request overview

Updates Helix queue definitions to run ARM containerized jobs on Azure Linux 3 ARM64 host VMs instead of Ubuntu 22.04 ARM hosts, aligning helix-platforms.yml with the host VM choice already used by other pipeline templates.

Changes:

• Replaced Ubuntu.2204.ArmArch.Open → AzureLinux.3.Arm64.Open for ARM container host VMs (public queues).
• Replaced Ubuntu.2204.ArmArch → AzureLinux.3.Arm64 for ARM container host VMs (internal queues).
• Applied the host VM update across ARM32 (glibc + musl) and ARM64 (musl) queue variables.

[github-actions]

🤖 Copilot Code Review — PR #126121

Holistic Assessment

Motivation: Justified. Ubuntu 22.04 host VMs are being phased out across the repo. AMD64 hosts were already migrated to AzureLinux 3 (see prior PRs #125991, #125995), and the helix-queues-setup.yml files for both CoreCLR and libraries already reference AzureLinux.3.Arm64[.Open] as the ARM host VM. This PR closes the gap for helix-platforms.yml.

Approach: Correct. The change is a mechanical find-and-replace of the host VM portion of the Helix queue strings (Ubuntu.2204.ArmArch[.Open] → AzureLinux.3.Arm64[.Open]). Container OS labels (in parentheses) and container images (@mcr.microsoft.com/...) are left untouched, which is exactly right since only the host running the containers is changing.

Summary: ✅ LGTM. Clean, focused infrastructure change. All 13 ARM host VM references are consistently migrated, matching the pattern already used by AMD64 entries and the existing helix-queues-setup.yml files.

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Detailed Findings

✅ Completeness — All ARM host VMs migrated

Verified all 13 Ubuntu.2204.ArmArch host VM references in the parent commit are changed to AzureLinux.3.Arm64:

• ARM32 Debian (latest/oldest, open/internal): 4 entries ✓
• ARM64 Ubuntu latest: 1 entry ✓
• musl ARM32 Alpine (latest/oldest, open/internal): 4 entries ✓
• musl ARM64 Alpine (latest/oldest, open/internal): 4 entries ✓

The one remaining Ubuntu.2204.ArmArch.Open at line 172 (helix_linux_arm64_oldest) is in the container OS label position (inside parentheses), not the host VM position — its host VM was already AzureLinux.3.Arm64.Open before this PR. This is correct: it identifies the test OS, not the host.

No other pipeline files under eng/pipelines/ reference the old Ubuntu.2204.ArmArch host VM.

✅ Consistency with existing infrastructure

The AzureLinux.3.Arm64[.Open] host VM values are already in active use:

• eng/pipelines/coreclr/templates/helix-queues-setup.yml (lines 87-110)
• eng/pipelines/libraries/helix-queues-setup.yml (lines 29-48)

This confirms the target queue names exist and are functional.

✅ Scope — No unrelated changes

Single file changed, single concern addressed. No code, API, or behavioral changes. Container images and container OS labels are preserved exactly.

Generated by Code Review for issue #126121 · ◷