The site is down
The training web service is not accepting requests. Inspect its state, bring it back, and verify the page responds.
InvestigateFix the system.
Build the instinct.
No command checklist. A starting condition, a concrete goal, and evidence that your repair worked.
Earn two practice stars for recovery and a third for diagnostic evidence. Hints never remove earned progress. Anonymous rewards last for this session. Signed-in practice rewards stay on this device and do not add competitive leaderboard XP.
The reload that failed
An invalid training configuration prevents nginx from starting. A known-good copy is available at /etc/nginx/nginx.conf.known-good. Inspect, restore, validate, then start the service.
InvestigateYour runbook is unreadable
Your private runbook is /home/learner/lab/private-note.txt. Recover owner-only read/write access, then read it. Do not grant group or public access.
InvestigateFind the rejected logins
Inspect /var/log/training-auth.log. Save only denied events to lab/denied.txt and their newline count to lab/count.txt. Leave the original log intact.
InvestigateThe missing homepage
nginx is active, but the root page is missing. A verified training copy is in /home/learner/backups/homepage.html. Restore /srv/www/index.html and verify it through HTTP.
InvestigateLeave a useful handoff
The runbook at /home/learner/lab/handoff-brief.txt states the incident name, observed state, and next action. Create lab/handoff.txt with those three exact key=value lines, keeping any credentials out.
InvestigateThe changed release artifact
Compare lab/release.txt with backups/release-approved.txt. Restore only the changed working copy, then verify identical digests. Do not modify the approved copy.
InvestigateA model is ready. The app is not.
Read /opt/ai-lab/incident.json. Identify the failing dependency and save its name followed by a newline in /home/learner/lab/dependency.txt. Model readiness alone does not explain application health.
InvestigateEarned through recovery
Repeat scenarios with fresh scratch state. The objective is safe understanding, not speed.