Check Linux CPU, memory, and disk pressure
Collect time-stamped capacity and pressure data before restarting services or resizing a host.
Read guide →THE OPERATIONAL KNOWLEDGE BASE
Fix what’s broken.
Learn how it works.
Practical Linux and DevOps guides for the moments you need to understand a system, solve a problem, and know what to check next.
incident-notes.md
01 Observe before changing
02 Make one safe change
03 Verify the result
04 Record what you learned
Logs > vibes. Verify before victory.
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START WITH THE FUNDAMENTALS
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LINUX ADMINISTRATION
Understand the system beneath your application.
Processes, services, filesystems, networking, and the shell.
Explore Linux →DEVOPS OPERATIONSWork confidently with delivery tools.
Git, CI/CD, Docker, Terraform, and Kubernetes.
Explore DevOps →TROUBLESHOOTINGMove from symptom to evidence.
Runbooks that help isolate failures and verify safe fixes.
Open runbooks →LATEST FIELD GUIDES
Useful answers for real work
Troubleshoot Linux firewall access safely
Confirm the service listener, active firewall manager, source path, and effective policy before a narrow rules change.
Read guide →Troubleshoot an expired or invalid TLS certificate
Inspect validity dates, hostname, chain, and clock at the endpoint that actually terminates TLS.
Read guide →Troubleshoot Kubernetes ImagePullBackOff
Check the exact image reference, registry response, pull credentials, namespace, node network, and platform compatibility.
Read guide →Troubleshoot a Kubernetes Pod that keeps restarting
Collect events, restart count, last termination reason, previous logs, probes, and resource limits to diagnose CrashLoopBackOff.
Read guide →Investigate an unexpected Terraform resource replacement
Read the plan’s replacement markers and compare configuration, state, provider version, workspace, and immutable attributes.
Read guide →LEARN BY DOING
Practice with real project resources
Curated tutorials from the projects behind the tools, with access conditions stated on each listing.
Browse hands-on labs →01Follow one guided exercise02Compare with upstream docs03Clean up resources you created
A CLEAR NEXT STEP
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View learning paths →OFFICIAL TRAINING · INDEPENDENTLY CURATED
Explore Linux Foundation training
Compare beginner Linux courses, operations training, and certification pathways using official course pages.
Browse course recommendations →LFS101Linux fundamentalsLFS207System administrationLFCSPerformance-based exam