Create day-07-linux-fs-and-scenarios.md

[praveenintune81-design]

Hi
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Scenario 1: Service Not Starting

Que:- A web application service called 'myapp' failed to start after a server reboot.
What commands would you run to diagnose the issue?
Write at least 4 commands in order.

Ans:-
1:- # systemctl status myapp # (shows myapp service running/stop/failed)
2:- Check recent logs.

journalctl -u myapp -n 50 # (shows error what the issue is, like config issue, port issue, permission issue)

3:-
systemctl is-enabled myapp # (this CMD enables server permanently; when the server is restart or boot the server server is running.)
4:-
systemctl daemon-reload
systemctl restart myapp # when apply any change, you need to restart service to apply changes

Scenario 2: High CPU Usage

Que:- Your manager reports that the application server is slow.
You SSH into the server. What commands would you run to identify
which process is using high CPU?

ans:-
1:-
run the # top (showing CPU/ram usage)
2:-

ps aux --sort=-%cpu | head -10 (show which process use heavy CPU)

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Scenario 3: Finding Service Logs
Que:-A developer asks: "Where are the logs for the 'docker' service?"
The service is managed by systemd.
What commands would you use?
ans:-

systemctl status docker (frist check docker running or stop)

journalctl -u docker -n 50 (show last 50 error/issue log)

journalctl -u docker -f

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Scenario 4: File Permissions Issue
Que:- A script at /home/user/backup.sh is not executing.
When you run it: ./backup.sh
You get: "Permission denied"

What commands would you use to fix this?

Ans:-

ls -l /home/user/backup.sh (show current permission if executable permission )

chmod +x /home/user/backup.sh (given executable permission)

./backuo.sh (run & check it)