worker-image-investigation

调查与worker镜像相关的Taskcluster任务失败问题。比较成功与失败的任务，提取镜像版本，查找正在运行的worker，并通过Azure CLI调试Windows VM。在图像升级后调试CI失败、调查间歇性测试失败或比较worker配置时使用。触发词包括“镜像调查”、“worker镜像”、“比较任务”、“为什么会失败”、“镜像回归”、“worker调试”。

Worker Image Investigation

Prerequisites

Install uv and taskcluster; add az for VM access. Follow fx-tests.md for XPCShell or Mochitest history.

Usage

SCRIPTS=~/.claude/skills/worker-image-investigation/scripts
export TASKCLUSTER_ROOT_URL=https://firefox-ci-tc.services.mozilla.com
uv run "$SCRIPTS/triage.py" <FAILING_TASK_ID>
uv run "$SCRIPTS/investigate.py" compare <PASSING_TASK_ID> <FAILING_TASK_ID>

Run investigate.py --help for image, SBOM, pool, and VM commands.

Investigation

Treat the triage.py verdict as a hypothesis; read the task log.
Check history with fx-tests or treeherder.
Compare an equivalent pass and failure (same revision, test, platform, configuration). A version difference is not proof.
Check today's equivalent baseline tasks. Shared failures, including Tier 1, do not block; failures against passing equivalents do. Read validation-gate.md before deciding.
Read azure-commands.md only when guest inspection is needed.

Gotchas

Passing retries can hide earlier harness failures; inspect full task logs.
--skip-treeherder drops history and classification evidence.
Missing fx-tests history means unknown, not new.
Some SBOM files need UTF-16LE decoding.
Debug VM names are at most 15 characters; take image and size from the pool config and delete the VM after use.

Related Skills

taskcluster (tasks), taskcluster-worker-lifecycle-logs (unclaimed tasks), papertrail (guest logs), worker-image-build (new build), bugzilla (confirmed regression).