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Clairos Learn

26 lessons · UNIX / Linux

Troubleshooting

A repeatable triage loop across resources, logs, services, network, and packages.

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What you will practice

Triage baseline; Failed service drill; Log correlation; Config diff triage.

Use the worked examples when needed, then test your understanding without them.

  1. 01Triage baselineStart troubleshooting with system, service, and capacity facts.Practice
  2. 02Failed service drillInspect an inactive service without restarting it.Practice
  3. 03Log correlationSearch multiple logs for related clues.Practice
  4. 04Config diff triageCompare configs before guessing at a routing issue.Practice
  5. 05Disk pressure reviewUse disk and log size commands in triage.Practice
  6. 06Permission denied triageInspect identity and file metadata before changing modes.Practice
  7. 07Network listener triageCompare sockets, firewall, and config.Practice
  8. 08Package change triageUse package logs to explain recent changes.Practice
  9. 09Rollback noteWrite a rollback note from evidence.Practice
  10. 10Troubleshooting checkpointComplete a focused triage loop.Practice
  11. 11Incident website downTriage a simulated website outage from service, config, and logs.Practice
  12. 12Incident disk fillingUse disk and log evidence for storage triage.Practice
  13. 13Incident bad deployCompare configs and hash scripts during deploy triage.Practice
  14. 14Incident unknown listenerMap a listener to process and firewall evidence.Practice
  15. 15Incident permission deniedInspect identity and modes before changing permissions.Practice
  16. 16Incident suspicious loginSearch auth evidence and SSH policy together.Practice
  17. 17Incident package regressionReview package upgrade evidence during triage.Practice
  18. 18Incident cron failureConnect cron schedule, service, and logs.Practice
  19. 19Incident backup inactiveTriage inactive backup state and manifest context.Practice
  20. 20Incident nginx config mismatchCompare active config and expected config examples.Practice
  21. 21Incident resource spikeBuild a resource snapshot before blaming a process.Practice
  22. 22Incident rollback evidenceCapture rollback evidence before writing a note.Practice
  23. 23Incident evidence bundleCollect service, log, and network evidence in one drill.Practice
  24. 24Final triage loopComplete a full triage loop with evidence and a final marker.Practice
  25. 25DNS and service triageSeparate local name-resolution evidence from web-service health.Practice
  26. 26Permission regression triageEstablish identity and metadata before applying a narrow repair.Practice