The interview process was online and consisted of six rounds.

The first round was with the engineering manager and served as a filtering stage. It was heavily focused on Linux and system debugging, particularly concerning performance issues. This round featured multiple scenario-based questions.

Following this, there was a series of interviews covering:

• Linux Administration
• Network Administration
• System Internals (IPC)
• Programming Round
• Googlyness Round

The process concluded with a Hiring Team review stage and the offer stage.

The entire process took approximately three to four months. The HR was fantastic and well-prepared. The interviewers were top-notch, delving deeply into each area and aiming for candidates to succeed.

System performance debugging:

• HTTP Proxy: How does it work?
• strace, truss: System calls and how commands interact with the kernel.
• IPC: How threading and processes interact with the kernel in Linux.
• Where do file names get stored? File name descriptors.
• CPU steal, nice, affinity with examples.
• Real-time performance issue that you solved recently: what tools were used and motivation behind using them.
• Disk I/O and its related tools and issues.
• Good practices for Linux hardening (many questions related to this).
• Networking and firewalls, Subnetting.
• TTL and how does it affect TCP vs UDP (Why UDP is preferred for video streaming and its disadvantage).
• Why DNS relies on UDP, not TCP.
• TTL hop counter load in top with extensive detail and its relation to the CPU core count.
• How does a TCP connection establish?
• How does a TCP connection finish (browser close)?

Programming round with language of choice:

• Interacting with API, building a parser to play on the API output.
• How you change your code with dynamic requirements.

Lots of behavioral questions during the Googlyness round, found it to be hard, to be honest. Interviewer was keen on why I made a decision and motivation behind it, and if I did a risk assessment before it.