After a few phone calls with an HR recruiter there was a tech screening interview. It lasted an hour and had maybe a dozen linux specific questions. I passed on the ones I couldn't answer 100% correctly and gave detailed explanations when possible. There was also time to ask the screener, who was also a consultant, questions about their job. I'd say that I had a good 2/3 of the questions answered with great detail. I traveled for an in person interview with the consultant manager and a senior consultant. It was fairly relaxed. There were some role playing questions, preparation for the amount of travel required, and general "why Red Hat?" questions.