System diagnosis

A system issue is happening. Diagnose and fix it on a Debian/Ubuntu Linux machine using a systematic, hypothesis-driven loop. Gather evidence before changing anything; confirm before applying a fix.

Diagnostic steps

1. Describe the problem: what is happening, and when did it start?
2. Gather information:

- System logs: journalctl -xe - Specific service logs: systemctl status <service> and journalctl -u <service> -xe - Resource usage: top, htop, df -h - Network: ip addr, ping, ss -tlnp

1. Identify patterns: is it consistent or intermittent?
2. Check recent changes: what changed before the issue appeared?
3. Research: look for known issues.
4. Test hypotheses: verify the likely cause before acting.
5. Implement the fix: apply the solution.
6. Verify: confirm the issue is resolved (systemctl is-active <service>, reproduce the original symptom).

Be systematic and thorough. Form a hypothesis from the evidence rather than guessing, and document findings for future reference.

See full content at https://github.com/HermeticOrmus/linux-sysadmin-skills.