Linux
Beginner
Storefront Stuck in Maintenance Mode
Every Northstar Shops storefront page answers 503 with the maintenance banner, and checkout has taken no orders for 20 minutes.
Free simulated incident practice
Practise explaining your incident investigation.
For a troubleshooting interview, the explanation matters as much as the command. Use a FixOps incident as a practice prompt: read the alert aloud, describe your assumptions, choose a check and explain how its result changes your hypothesis. The incident is simulated; your reasoning is the part to rehearse.
Turn the alert into a clear question
Begin with the affected service, the user impact and what is still unknown. State which evidence would change your mind. Avoid naming a root cause before you have observations to support it.
Narrate your decisions
Before each check, say what you expect and what you will do if the result differs. Prefer a small number of purposeful checks to a long list of commands. If you reach for a hint, explain what you learned from it after the attempt.
Close with recovery and prevention
Explain the change, the evidence that the system recovered and one follow-up you would investigate in a real environment. Repeat the scenario later without your notes, or choose an unfamiliar category to test whether the method transfers.
Put the method into practice.
Open a brief to see the symptoms, then launch the incident. The solution is yours to find.
Networking
Intermediate
Storefront API Calls Fail
Storefront pages load again, but cart, search and checkout calls through /api fail for every customer.
Security
Intermediate
Developer SSH Login Is Rejected
The dev automation account's SSH logins from the deploy runner are refused, and scheduled deploy jobs cannot reach the host.
Docker
Intermediate
Web Container Is Unreachable on Port 80
Browser customers get connection refused on port 80 while the storefront's web container reports Up.
Kubernetes
Intermediate
API Pods Restart Across the Rollout
Every api replica is in CrashLoopBackOff and the Deployment has shown 0 of 3 available for ten minutes.
Git
Intermediate
Checkout Errors Rise After Release
Checkout's error rate jumped from about 0.2% to 23% within minutes of the latest configuration release.
Web
Intermediate
Order API Returns 502 Through Nginx
Every order API request through the edge returns 502 Bad Gateway, so checkout cannot submit orders.
Cloud
Advanced
Object Requests Failing Across nbx-east-1
GET, LIST and PUT requests fail for every customer in nbx-east-1, and new uploads cannot be placed.
CI/CD
Intermediate
Deploy Workflow Stops Before Any Job Starts
The deploy workflow is rejected before any job is scheduled, so none of tonight's changes can reach production.
What kind of lab is this?
FixOps runs simulated systems and a terminal designed for its scenarios. It does not provision a real server or cluster. Use it to rehearse investigation and recovery, and use a real environment when you need unrestricted tooling or production experience.
There is no interview pass guarantee or certification. You can start as a guest in the browser or use the Android app. If the concepts feel unfamiliar, work through a learning track before trying another incident.
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