3.3 KiB
Practice Exam - Betriebssysteme und Netzwerke
Exam Information
- Duration: 45 minutes
- Tasks: 5 problems to diagnose and fix
- Allowed: 1x A4 cheat sheet (front and back)
Scenario
You are a system administrator for a company. Multiple services on the server have stopped working after a colleague made some changes. Your task is to diagnose and fix all issues.
Task 1: Company Portal Unreachable
Service: http://company.local
Problem: The company portal website is not loading. Users report seeing an error page or the page won't load at all.
Expected Result: The website should display "Company Portal" with "Status: Online"
Test Command:
curl http://company.local
Category: Web Server Configuration
Task 2: Online Shop Shows 403 Forbidden
Service: http://shop.local
Problem: The online shop returns a "403 Forbidden" error when accessed.
Expected Result: The website should display "Online Shop" with "Status: Online"
Test Command:
curl http://shop.local
Category: File System Permissions
Task 3: API Returns 502 Bad Gateway
Service: http://api.local:8080
Problem: The REST API returns a "502 Bad Gateway" error instead of JSON data.
Expected Result: The API should return a JSON response with "status": "success"
Test Command:
curl http://api.local:8080
Category: Service Management (systemd)
Task 4: Docker Application Unreachable
Service: http://localhost:8888
Problem: The Docker web application running on port 8888 is not accessible. The connection times out.
Expected Result: The page should display "Docker Application" running in a container.
Test Command:
curl http://localhost:8888
Hint: The Docker container itself is running correctly.
Category: Firewall (UFW)
Task 5: Database Connection Refused
Service: MySQL Database
Problem: The web application cannot connect to the MySQL database. Connection attempts with the webuser account are being refused.
Credentials:
- Username:
webuser - Password:
WebPass123! - Database:
practicedb
Expected Result: Should be able to connect and query the database.
Test Command:
mysql -u webuser -p'WebPass123!' practicedb -e "SELECT * FROM products;"
Category: Database Administration
Verification
Run the verification script to check your progress:
sudo ./break_server.sh
# Then select option 7) Verify all services
Or test each service manually with the curl commands above.
Diagnostic Commands Reference
| Tool | Purpose |
|---|---|
systemctl status <service> |
Check service status |
systemctl start/restart <service> |
Start or restart service |
nginx -t |
Test nginx configuration |
journalctl -u <service> |
View service logs |
ufw status |
Check firewall rules |
ss -tulnp |
Show listening ports |
ls -la <path> |
Check file permissions |
docker ps |
List running containers |
cat /var/log/nginx/error.log |
View nginx error logs |
Good Luck!
Remember to work systematically:
- Identify the symptom
- Check service status
- Review configuration/logs
- Apply the fix
- Verify the solution
Practice Exam - Betriebssysteme und Netzwerke