Interview Guide for Infrastructure Engineering

General Info

• We will ask you to answer questions related to 5 infrastructure topics within 50 minutes. (check before you start).
• You will be able to decide which section to do first and jump back and forth between sections, so don’t panic if an improvement comes to mind unexpectedly.
• Don’t forget to submit your solution before time expires.

A few things to cover before you start

• This is not your classic engineering set where you will be tested on algorithms and data structures.
• Prepare for questions related to Network Security, AWS, AWS security, Terraform and Networking.
• The tasks are timed so make sure you set your working environment accordingly and you won’t be disturbed.

This is no secret but the interviewing environment is slightly different from your day-to-day work. With this in mind, make sure you will spend some time on preparation. Those who practice, perform better.

*Please note that some roles within Infrastructure space may have a slightly different Hackerrank interview structure. Your recruiter will share further details.

The interview will start with introductions (5 mins), a short setup step (5 mins) where you will be given temporary credentials and some code to work on, after which the coding test will begin. This is a live test whereby we provide you with a repository containing TF code and some supporting elements (such as a Makefile to run things). We’ll ask you to download a repository so you can work through some issues and additions, base infrastructure is deployed to an AWS account prior to the test. 

This test is focused on cloud infrastructure and debugging skills; we use it to assess your knowledge of AWS, Terraform and problem-solving skills. The technical portion of the interview will take roughly 45 mins, there will be 5 mins at the end of the interview for Q&A.

The test can be conducted on ECS or EKS, please let your recruiter know ahead of the interview which version of the test you would like to take.

We will provide the following at the start of the interview

• AWS account login
• Repository containing infrastructure code

You will need the following:

• Tfenv (link) 
• An IDE
• BASH compatible shell
• Git
• LLM tooling must be disabled (eg. Copilot)

Please be ready to share your screen during the interview.

Worth remembering!

• Work through each task methodically
• Be ready to share your screen during the interview
• Let your recruiter know if you want the ECS or EKS version of the test

Assessment rubrics | What interviewers look at 

Cloud Knowledge – you are expected to have detailed working knowledge of AWS.

Problem-Solving – you will be presented with live issues that will involve a mix of skills, including debugging to understand the solution.

Communication – Ask questions, and discuss your thoughts or any problems you’re having. Engineering is collaborative – so is the interview.

There are hundreds of services worked on by dozens of engineering teams and they all need to work seamlessly together to get that burger to you at 7pm on a Friday. This means it’s really important that our engineers can reason about and design complicated interacting systems that can handle the scale Deliveroo operates at.

Response framework:

• Clarify the problem.
• Break down a complex element into parts. Identify components.
• Discuss and iterate on your solution with your interviewer. Identify and analyse design trade-offs.

Your interviewer will ask questions to dive deeper into some parts of your design.

How to prepare?

• Read up about infrastructure platforms that operate at a large scale; how do they manage many requests? How do they cope with things that go wrong?
• Try out system design problems on the web!
• Feel free to use any stack you’re familiar with, we’re interested in why you make the choices, not what choices you make. Be ready to discuss how your decisions affect the user of the platform you’re designing and any trade-offs you’re making.
• Get familiar with a whiteboarding tool (we recommend Draw.io!) Prep your device so you are ready to share your screen.

This interview looks at how you handled specific challenges in the past to assess if you will be a good match for the role. Some of the areas we address are:

• Communication
• Team management
• Leadership
• Problem-solving
• Flexibility and can-do attitude Initiatives and growth mindset
• Organisation and self-development
• Decision making

We care about our culture as much as we care about our products! Have a look at our Deliveroo Values:

Live and breathe our marketplace

Being deeply immersed in all sides of our marketplace, and each and every neighbourhood we serve.

Play to win

Setting bold targets and seeing them through with tenacity, creativity and grit.

Celebrate difference

Advocating for respect and fairness for everybody, understanding we are all individuals on a unique journey.

Champion big and small innovations

Innovating no matter what our role is, and celebrating achievements no matter the size.

Obsess about operational excellence

Leaving things better than we found them, investing both our time and money in the things customers care about.

Be curious and intellectually honest

Thinking deeply and debating each other with respect while keeping our biases in check.

Take a look at our few examples

Tell us abouta time when you failed to meet a deadline. What did you fail to do? What did you learn? Before answering have a think about:

• The root cause.
• Why did it seem like a good idea at the time?
• How did you apply what you learned afterwards?

Describe to us a specific task or a challenge that you were facing and how you made sure in successfully completing it. What were the key factors of this success?

• Be clear up front about your objectives and wider context.
• Reasons you chose those particular strategies and tools to complete it.
• Any measures you had in place to monitor your progression?
• Main obstacles that you had to address and things learned along the way.

Provide an example of the time when you had a difference of opinions with one of your colleagues regarding a project you both worked on and how you arrived at the conclusion. Before answering have a think about:

• Specify the situation, differences of opinions and other important context.
• What data, tools or information did you use to support your idea?
• How did this discussion end and impact your future cooperation?