The entire process was very easy and friendly. Red Hat puts quite a bit of weight into employee referrals. My initial contacts were with the same person in HR who was very responsive over email and phone. Since I don't live near the main headquarters, I was able to do all of my interviews over the phone. One of which, I went into one of their sales offices to use a conference room. I had 3 or 4 interviews with engineers and direct managers on the team (nobody from HR). They asked a few stock scenario type questions ("Tell me about a time you ..."). Then the rest of the time was technical discussions (didn't really feel like an interview, just like chatting over coffee). The interviewers had obviously read my resume and dug into some projects and were curious about details.