Meta Production Engineer interview questions

You gain access to a 10000 node botnet and they want you to crawl a website with it. Design the system

# Interviews ### Screening - **Round-1 Behavioral/Managerial** - *1.* Describe about current project, How its challenging? - *2.* How your work impacts customer? - *3.* How you try to innovate - **Round-2 //Coding** - *1.* [PrintFastestToSlowestDianosaurs_fromCSV - *2.* Find Battleship in 2-D matrix ### Onsite Interviews - **Round-1 //Systems/Unix** - *1.* Signals, Interrupts, IVT? SIGINT, SIGTERM. kill sends which signal? - *2.* Process memory layout? - *3.* Stack overflow, heap overflow? - *4.* How system call goes from user from kernel space? - **Round-2 //Coding** - *1.* [mindsweeper grid design] - *2.* [Can array is split into 2 halves] - **Round-3 //Design** - *1.* Design botnet. botnet can exploit 10000 low end machines to run code. All machines need to crawl webpage and return result. No machine should crawl page again. - Interviewer's feedback: - *a.* Candidate is not into system design, not aware about designing Large systems. - *b.* Did not came up with final design - *c.* I have not written code - *d.* They need someone with greater exposure to System Design for this position. <<And should be - **Round-4 //Networking** - *1.* What's your fav protocol(ipsec)? - What its flow? - What are drawbacks/improvements in it? - *2.* Http1.2 vs 1.3. Carrying Http over UDP? - *3.* Everything that happens on when on browser fb.com is searched. DNS, ARP, Routing tables etc - This was intense interview, Interviewer wanted to ask how QUIC protocol is better on TLS wrt TLS over TCP. Why TCP congestion control is problem and how we can remove that. - **Round-5 //System** - *1.* Interprocess Communication mechanisms(Pipes, named pipes, SM, MQ, sockets) - How they work internally, Adv/disadv of each, their code. - Is data copied in kernel buffers or remains in user space only? - can more than 1 process write on pipe at a time? - Code for every IPC mechanism, APIs and their parameters. - **Round-6 //Behavioural** - **Remember: This is not Technical round, Donot go Technical** - *1.* Tough project - *2.* disagreement in team. - *3.* Bad or good manager # Preparation - After clearing the screening round I took time of 1.5 month for preparation Material: //Coding: Leetcode coding question (facebook specific) //Unix Operating system (Tenanbam-Modern Operating Systems 4th Edition) //Networks (Computer Networks-Tanenbaum-5th edition) //System Design (Distributed_Systems_Tanenbam_3rd_edition) I believe its best we should read good books instead of reading thru the internet. Best of Luck.