Lab: CrashLoopBackOff
A service crash-looping after a routine config change, with logs that show a normal startup and no error anywhere. Work out what is killing it.
intermediate· 25 minKubernetes
Practice
Labs
Reading about a failure and diagnosing one are different skills. Labs drop you into an incident with the same partial, noisy information you would have in production, and ask you to work it out before showing you the answer.
How a lab works
Six stages, in the order a real investigation goes — not the order a tutorial would put them in.
- 01
Scenario
You are handed a failure and the context an engineer would actually have. Nothing is pre-diagnosed.
- 02
Signals
Realistic command output, logs, and service state. Some of it is relevant. Some of it is not.
- 03
Investigate
You decide what to run next. The lab tells you what each command would have returned.
- 04
Hypotheses
Rank what could produce these signals, and identify which check eliminates the most possibilities.
- 05
Root cause
The explanation, including why the obvious first guess was wrong.
- 06
Fix and validate
Remediation, the validation that proves it worked, and the rollback if it did not.
Labs
Available labs
Introductory labs are free. Advanced labs are part of Pro.
Lab: Nova NoValidHost
Instances stopped building on a cloud with visible free capacity. Work the evidence, form hypotheses, and find why the scheduler has no candidates.
expert· 35 minOpenStackNova
Lab: Destructive Plan Review
A routine-looking Terraform pull request. Find the changes that would destroy data before you approve it, and work out which one is not what it appears to be.
intermediate· 20 minTerraformAWS
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