Technical interview guide

ROS (Robot Operating System) Fundamentals

The de facto standard middleware for robotics software — nodes, topics, and services that let components communicate.

Read: 45 min
Practice MCQs: 25
Interview QA: 25
Edition: v4
Editorial status: Reviewed
Relevant for: Robotics Engineer

Scope: ROS 2 Rolling node, topic, service, action, QoS, executor, callback-group, lifecycle, tf2, parameter, security, rosbag2, and composition documentation reviewed 2026-09-04.

Interview QA

Treat each question like a live interview question: answer out loud first (structure, assumptions, tradeoffs), then open the model answer to spot gaps and rehearse a tighter follow-up.

Curated: 2026-10-05 · Written: 2026-10-05 · Reviewed: 2026-10-03

QA-1

Choose node and process boundaries for a robot subsystem.

QA-2

Choose topic, service, or action for an interface.

QA-3

Design an action server for robot motion.

QA-4

Specify and test a topic QoS contract.

QA-5

Choose QoS for high-rate sensor data versus a safety command.

QA-6

Use transient-local durability without replaying stale control.

QA-7

Design executor placement for sensing, control, and logging.

QA-8

Prevent callback-group deadlock.

QA-9

How do you achieve thread-safe shared state management between subscription callbacks and timer callbacks in a MultiThreadedExecutor?

QA-10

Specify time semantics for a ROS system that runs live and in simulation.

QA-11

Design a correct tf2 lookup and failure policy.

QA-12

Design safe multi-parameter reconfiguration.

QA-13

Orchestrate lifecycle for sensor, localization, planning, and control nodes.

QA-14

Choose composition boundaries for a high-bandwidth perception pipeline.

QA-15

Design names and remaps for a multi-robot deployment.

QA-16

How do ROS 2 Managed (Lifecycle) Nodes work, and what are the primary lifecycle states and transitions?

QA-17

How does rosbag2 record and replay topics, and how is simulation time handled during replay?

QA-18

Evolve a ROS message contract safely.

QA-19

How do parameters work in ROS 2 compared to the ROS 1 Parameter Server, and how can node parameters be declared, monitored, and dynamically reconfigured?

QA-20

Design graceful and forced shutdown for a robot process.

QA-21

Instrument ROS callback and graph performance.

QA-22

Build deterministic ROS 2 integration tests in CI.

QA-23

Review a production ROS launch and deployment.

QA-24

Design startup readiness beyond ROS graph discovery.

QA-25