Oracle Linux, Networking & Scripting interview questions

Two different resources produce the same errno, and the second one is invisible unless you know to look. One command distinguishes them.

A beginner question with a senior follow-up hiding in it. Once you know a hard link is a second name for an inode, log rotation and backup behaviour both stop being mysterious.

The two-syscall duet behind every process on the box. The follow-ups live in what survives the transition, and candidates who skip that fail the next question.

A routine cloud operation with three layers that can quietly disagree. The strong answer is an ordered procedure you could run during business hours, without a reboot.

Enterprise loops pair these topics because they test L2 literacy plus vendor coordination together. The scored insight is that LACP spreads flows, not packets, and needs the switch to agree.

Everyone knows ulimit -n. The interview question is which process inherits which value, why limits.conf did nothing for your service, and how you size the ceiling honestly.

Patching is easy; surviving the rollout is the interview. Staged rings with health gates, what livepatching can and cannot buy you, and the rollback plan you write before starting.

Copy-on-write freezes a point-in-time view while the database keeps writing. Fat snapshots overflow into invalid backups and thin pools exhaust into frozen volumes: size both deliberately.

Transparent versus explicit hugepages is a control question, not a size question. Fork-heavy stores suffer THP copy-on-write amplification while large-resident databases gain TLB reach.

The question that separates people who have debugged a hung rollout from people who have read about one. The interesting half is not the signal, it is PID 1.

A staple of every networking round, and the follow-up is always about TLS termination. Knowing which layer sees what decides most of the answer.

The oldest question in systems interviewing and still the best, because it is unbounded: the interviewer stops you when you run out of depth, and where you stop is the score.

The question that reveals whether someone knows what load average actually counts on Linux. It is not a CPU metric, and that single fact resolves the whole thing.

The classic ephemeral port exhaustion question. Most candidates know the phrase TIME_WAIT; far fewer know which side accumulates it and why the popular fix is dangerous.

The scripting round in disguise. The constraint is the question: it exists to see whether you stream or whether you load, and everything else is about whether the script is safe to run twice.

Everyone recites the four letters. The scoring answer walks each packet across the wire and knows the places the exchange silently dies.

Interviewers use this to sort memorised trivia from people who have chased a slow lookup. Three roles, one bit, and the caching rules most candidates repeat incorrectly.

The answer is yes, and then the real question starts. Asymmetric routing and silent drops punish anyone who treats the routing tables as one flat list.

A growing backlog of sockets waiting for the application to close its side usually points at lifecycle handling. Here is the hunt from ss output to the pool timeout that caused it.

Most hand-written units boot in dev and die in production. The gap is Type selection, restart policy, and the drop-in workflow vendors expect you to respect.

A one-line mistake that locks you out of the obvious fix. The fast recovery teaches more about the permission model than any man page will.

Most candidates can recite the flags. The scored part is proving you can capture on a saturated box without adding load, then read the file afterward like evidence.

Two authentications happen in every SSH session and most candidates narrate only one. Knowing who proves what, and where your agent socket ends up, is the scored material.

Every ops engineer schedules jobs; few can say which shell cron uses, where stdout lands, or why percent signs delete half a command. Those gaps are exactly what interviews test.