fix: filter apt list by CPU architecture to prevent cross-arch kubelet install failures

[djsly]

Summary

Fixes a bug where installPkgWithAptGet in Ubuntu CSE picks arm64-only package versions on amd64 nodes, causing kubelet download failures (404).

Root Cause

apt list --all-versions returns entries for all architectures:

kubelet/noble 1.34.0-ubuntu24.04u6 arm64
kubelet/noble 1.34.0-ubuntu24.04u5 amd64
kubelet/noble 1.34.0-ubuntu24.04u5 arm64

The existing grep pipeline only filtered by k8s version (e.g., 1.34.0), so sort -V | tail -n 1 could select a version that only exists for arm64 (u6). When an amd64 node then calls apt-get download kubelet=1.34.0-ubuntu24.04u6, it fails with 404.

Fix

Added grep "$(getCPUArch)" to the pipeline to filter apt list output to only the current node's architecture before selecting the latest version:

# Before (broken)
fullPackageVersion=$(apt list "${packageName}" --all-versions | grep "${packageVersion}" | awk '{print $2}' | sort -V | tail -n 1)

# After (fixed)
fullPackageVersion=$(apt list "${packageName}" --all-versions | grep "${packageVersion}" | grep "$(getCPUArch)" | awk '{print $2}' | sort -V | tail -n 1)

getCPUArch is already defined in cse_helpers.sh and returns "amd64" or "arm64".

Impact

Users reported kubelet download failures on Ubuntu 24.04 amd64 nodes for k8s 1.34.0 and 1.34.1:

• kubelet_1.34.0-ubuntu24.04u6 — arm64 only, no amd64
• kubelet_1.34.1-ubuntu24.04u5 — arm64 only, no amd64

Testing

• GENERATE_TEST_DATA=true go test ./pkg/agent/... — all pass
• Snapshot test data unchanged (shell script change, not Go template)

AB#38257849

[Copilot]

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.

[Copilot]

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.