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Troubleshooting Lab Guides

Reproducible, hypothesis-driven experiments that recreate real Azure Monitor failure modes end-to-end, then prove the fix with collected evidence. Where the Playbooks tell you how to diagnose a live incident, lab guides let you reproduce the failure in a controlled environment so you can build intuition before you face it in production.

How Lab Guides Differ from Playbooks

Aspect Playbooks Lab Guides
Goal Diagnose and resolve a live incident Reproduce a failure to learn its signature
Starting point An active symptom A clean environment you deliberately break
Outcome Restored service A confirmed hypothesis backed by evidence
Reusability Reference during an incident Run as a self-contained exercise

Lab Methodology

Every lab guide follows the scientific-method skeleton so the result is reproducible and falsifiable, not anecdotal:

  1. Background — the question the lab investigates and the environment it needs.
  2. Hypothesis — the expected cause and an "IF … THEN …" prediction.
  3. Runbook — the steps to deploy the environment, trigger the failure, and apply the fix.
  4. Experiment Log — the observed evidence, tagged for strength ([Observed], [Measured], [Inferred]), including a Falsification step that proves the fix works and the original theory was correct.
  5. Verification — the KQL queries and portal evidence that confirm the outcome.

Available Labs

Each published lab is added as a file under docs/troubleshooting/lab-guides/ and as a nav entry in mkdocs.yml. Live evidence capture status is called out explicitly so documentation-first labs do not imply fabricated proof.

Lab Failure Mode Status
AMA Heartbeat Loss DCR association deletion makes Heartbeat stale even though the VM and AMA extension still exist Documentation published; pending live capture
Application Insights Telemetry Gap Invalid APPLICATIONINSIGHTS_CONNECTION_STRING stops fresh AppRequests from arriving until the original value is restored Documentation published; pending live capture

See Also

Sources