NVIDIA Linux, Networking & Scripting interview questions

The swap-used graph is the least informative memory metric on the box. Here is what swappiness actually weights, which numbers to watch instead, and the policy worth defending.

SIGKILL writes no stack trace and the application cannot defend itself. The verdict is already sitting in the kernel ring buffer, and reading it precisely is the skill being priced.

One CPU doing all the packet work is a topology failure, not a tuning mystery. RSS queues, MSI-X vectors, local_cpulist and irqbalance: the whole chain from symptom to pin.

Most throughput tests measure the tester, not the network. Single stream versus parallel, slow start, sender-side retransmits, and the CPU ceiling: how to produce a number you can act on.

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.

Ordering and retransmission are what TCP adds, and both of them cost time. Naming something that deliberately gives them up, and saying why, is what turns a textbook answer into a real one.

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: every layer you can describe is another layer you could debug.

Five stages, and which one you are stuck in tells you what to fix. A machine that reaches a GRUB prompt has a different problem from one that hangs waiting on a filesystem that no longer exists.

The classic ephemeral port exhaustion question. TIME_WAIT is a familiar phrase and the useful facts are narrower: which side accumulates it, and why the popular fix is dangerous.

The arithmetic takes thirty seconds to learn and gets asked constantly. What it is really testing is whether you have ever had to size a VPC that could not be resized later.

Most of what looks like used memory on a healthy Linux box is page cache doing its job. Knowing which column to read, and why df and du disagree, is half of Linux triage.

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.

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.

Two authentications happen in every SSH session, and the one usually left out is the server proving itself to you. Knowing who proves what, and where your agent socket ends up, is the scored material.

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.

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.