Meta Production Engineer Interview Guide

This round is typically part of the internship application process and involves an online Linux questionnaire that takes about 18-20 minutes to complete. The questionnaire consists of approximately 20 questions covering basic Linux systems and commands, operating systems concepts, and networking.

For instance, you may be provided with two CSV data files—one of which will contain statistics about dinosaurs, and the second will contain additional data. You will then be asked to process the data and print the names of dinosaurs from fastest to slowest.

To prep for this round, 

• We suggest familiarising yourself with the basics of Linux systems, networking, operating systems Concepts, and commonly used commands. 
• It would be beneficial to review essential topics such as process scheduling, network protocols, IP addressing, subnetting, basic troubleshooting techniques, memory management, file systems, and so on. 
• Also, look for sample Linux, operating systems, and networking questions online, and try your hand at solving them.

The coding interview is a challenging 1-hour session where you will demonstrate your ability to think logically and code accurately under pressure. You will be presented with two data structure and algorithm coding problems. These can cover various topics such as BFS/DFS graph traversal, string manipulations, tree operations, and so on.

As you progress, the interviewer will keep adding on details to assess your problem-solving skills and evaluate your code for clarity, accuracy, efficiency, and speed.

Here are common questions you could be asked:

• Implement a depth-first search (DFS) algorithm to traverse a binary tree and print its elements.
• Implement a function that finds the kth smallest element in a binary search tree (BST).
• Given a string, implement a function to check if it is a palindrome.
• Implement a function that reverses a linked list.
• Given an array of integers, find the maximum sum of any contiguous subarray.

To prep for the coding round, make sure you have a solid understanding of essential data structures like arrays, linked lists, stacks, queues, trees, and graphs. Practice solving common algorithms on platforms like LeetCode, HackerRank, etc.

Then, you can move to code on a whiteboard or paper without the aid of an IDE or compiler. Or better yet, practice with a mock interviewer; you can book a "coding style" interview with one of the Meta Production Engineers at Prepfully for a simulated experience.

This is roughly a 45-minute systems interview that focuses on responding to real-world situations. This is probably the most complex and diverse segment; questions cover the breadth of topics like OS system call (finding stack information or what files are being called for deep performance analysis), tcpdump, and more importantly, linux troubleshooting and debugging. It will also touch upon topics like tooling, memory allocation, swapping, Linux processes, and UNIX process lifecycle. 

It typically commences with a high-level troubleshooting of a likely scenario, such as an unhealthy web server or database. You are then asked to probe deeper into the issue, identify the root cause, and propose potential solutions. The objective is to assess your understanding of systems at scale and their behaviour under load. 

This interview will likely challenge your boundaries of what you know and whether you can implement it. What tools might you use to debug something? Do you have an understanding of things like IO, CPU, shell, memory? If you know how to actually write a UNIX shell? Keep in mind the challenges of the Meta's environment when leveraging Linux processes, threads, memory, system calls to address the problem.

There are several excellent Linux preparation books you can leverage to prep for this round, such as "Advanced Linux Programming," "Linux Kernel Development" by Robert Love, and "Systems Performance" by Brendan Gregg.

The Design/Architecture Interview revolves around tackling an ambiguous question on how to build a system and skillfully guiding the interviewer through the process. For instance, you might be asked—

• How would you design a scalable messaging platform?
• What considerations would you take into account when designing an e-commerce checkout system?

Throughout the interview, your task is to develop a simple and practical solution while taking into account any constraints that the interviewer may introduce. Factors such as load and monitoring should be taken into consideration, and it's equally important to be aware of what not to consider. 

Therefore, don't hesitate to ask clarifying questions and gather requirements as needed. For instance, "Could you provide more details about the expected user load or the expected number of concurrent users?" OR "Are there any specific performance or latency requirements for this system? OR "Should the system prioritize fault tolerance or speed of execution?"

Interview Questions

• Find an almost palindrome.
• How is virtual memory managed on Linux?
• Split an array so that the sum is the same for both partitions.
• Read two CSV files, calculate based on the data in these files.
• What are the daily tasks of a production engineer?
• How does your work impact customers?
• How do you foster innovation in your work?
• Write a script that connects to 100 hosts, searches for a specific process, and sends an email with a report.
• Read data from an API call in JSON format, organise it as requested.
• Read an input file, parse the strings, and count the occurrences of email addresses.
• Given the formula: speed = ((STRIDE_LENGTH / LEG_LENGTH) - 1) * SQRT(LEG_LENGTH * g) (where g = 9.8 m/s^2, the gravitational constant), write a program to read data files, and print the names of bipedal dinosaurs from fastest to slowest.
• How does the Linux kernel handle process scheduling and what algorithms are involved?
• What is the role of the virtual file system (VFS) in the Linux kernel?
• How would you implement a solution for the two-sum problem using Python?
• Can you describe an efficient algorithm for finding the longest substring without repeating characters?
• What is the difference between a process and a thread?
• How does Linux handle inter-process communication (IPC) and what are some common mechanisms used?