I was approached by a recruiter through LinkedIn.

We first had an informal call. After some general chat, the recruiter asked if I'd like to proceed to a technical screening, which I accepted.

This screening involved a series of questions related to networking, processes, and Linux administration. The questions were not in-depth but aimed to gauge my overall orientation. Following this call, we agreed to schedule a technical interview.

The technical interview included two relatively involved but still fairly easy questions concerning navigation through tree and graph data structures. The next day, I received a call and was invited directly to an onsite interview.

The onsite consisted of five whiteboard problem-solving sessions, with a lunch break in between. The coding tasks were fairly easy. However, the interviewers did not ask to optimize the solutions, which proved to be the critical point. They expected me to be proactive and suggest improvements without prompting.

There was also a NALSD (Network and Linux System Design?) session and a troubleshooting session. Both of these apparently went worse than expected, though also better than I anticipated, given my limited prior experience in these areas.

Overall, the process was very smooth. Google demonstrated amazing patience regarding my limited availability. The recruiters were very friendly, the interviewers very kind, and the questions were interesting and challenging.

I did notice one of the interviewers seemed unsure of the details of the internals he was asking about, which surprised me. The outcome also surprised me, as they were quite selective while exhibiting some lack of knowledge themselves. Nonetheless, I felt they were all very engaged, experienced, smart people, genuinely interested in learning about my skills.

The entire process took a long time, but this was because I specifically requested they wait for my availability, which they did without any complaint. I can only wholeheartedly admire this.

I haven't signed any NDA, but was informally asked not to share the questions.

You need to refresh your algorithms and data structures, system administration, and coding skills. Get familiar with the SRE type of work, problems, etc. It's best if you can get a grip on their recently released book (check with O'Reilly).