Observability and tracing · Lesson 6 of 15 · 9 min

Follow a request trace

A trace follows one request through its spans. Use parent-child relationships and IDs so unrelated concurrent work does not get included in the incident path.

Open the lab Course map

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learner@clairos:~ $

↑ history · Tab complete · Ctrl+C cancel · Esc, Tab to leaveExit 0

Your objectives

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1
Read the case evidence
Read /opt/ai-lab/cases/aiops-observability-tracing-006.json. Separate the recorded facts from your assumptions.
Hint & worked example
A trace follows one request through its spans. Use parent-child relationships and IDs so unrelated concurrent work does not get included in the incident path.
The complete case JSON is read successfully.
```
cat /opt/ai-lab/cases/aiops-observability-tracing-006.json
```
Common mistake to avoid: Add all spans from other traces because they ran at the same time.
2
Isolate the deciding signal
Select the children field from the case JSON. What does it establish—and what does it not establish?
Hint & worked example
Follow retrieve-07 and infer-07 within trace-07.
A successful JSON query isolates children.
```
jq .children /opt/ai-lab/cases/aiops-observability-tracing-006.json
```
Common mistake to avoid: Using a different case or an unrelated signal as the justification.
3
Record your operational decision
Choose the justified code: follow-related-spans, change-without-evidence, or ignore-the-signal. Save that one code followed by a newline in /home/learner/lab/aiops-observability-tracing-006-decision.txt.
Hint & worked example
Follow retrieve-07 and infer-07 within trace-07.
The decision artifact contains the correct code, not just a matching command in history.
```
printf '%s\n' 'follow-related-spans' > /home/learner/lab/aiops-observability-tracing-006-decision.txt
```
Common mistake to avoid: Add all spans from other traces because they ran at the same time.

Understand the pattern

A trace follows one request through its spans. Use parent-child relationships and IDs so unrelated concurrent work does not get included in the incident path.

Interpret the evidence

Follow retrieve-07 and infer-07 within trace-07.

A tempting mistake

Add all spans from other traces because they ran at the same time.

All names, measurements, prices, versions, and thresholds in this exercise are fictional training data. The evidence supports this bounded scenario, not a claim about a live provider.

Worked example and expected result

$ cat /opt/ai-lab/cases/aiops-observability-tracing-006.json

{
  "fixture": "Fictional training data; not a live measurement.",
  "trace_id": "trace-07",
  "root": "gateway",
  "children": [
    "retrieve-07",
    "infer-07"
  ]
}

Exit status: 0. The command completed successfully in the training fixture.

$ jq .children /opt/ai-lab/cases/aiops-observability-tracing-006.json

[
  "retrieve-07",
  "infer-07"
]

Exit status: 0. The command completed successfully in the training fixture.

$ printf '%s\n' 'follow-related-spans' > /home/learner/lab/aiops-observability-tracing-006-decision.txt

(no output; exit 0)

Exit status: 0. The command completed successfully in the training fixture.

Try a variation

Name the assumption that would have to change for “follow-related-spans” to stop being the justified action. Do not silently replace missing evidence with a guess.

Explain it

What does the evidence in “Follow a request trace” justify?Follow retrieve-07 and infer-07 within trace-07.Add all spans from other traces because they ran at the same time.Make the change now and gather the missing evidence afterward.

Apply it elsewhere

A colleague concludes: “Add all spans from other traces because they ran at the same time.” What should you do?Accept it because the training command completed.Treat this fixture as a live measurement.Reject that conclusion; return to the case evidence and its stated limits.

Keep the momentum.

Complete the lab, then explain and apply the pattern.

Next: Find a slow span Try an incident drill

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Keep learning

Case methodology: evidence, limits, decision