The Tech Interview Behind the Scenes: Konstantin Petrov

The Tech Interview Behind the Scenes is an HRLabs series.
Let’s take a look behind the scenes of the technical interview process from the interviewers' perspective.
Our goal is to provide candidates with valuable tips and recommendations directly from professionals who conduct interviews for various technical roles.

“What matters most is showing passion for what you do and a strong desire to continuously build on your skills.", shares Konstantin Petrov, Lead DevOps Engineer at Ship.Cars.

Tell us more about your career path.

Initially, my career was focused on telecommunications, as that was my university specialization. I started as a NOC operator and later worked as a PreSales engineer. After that, I joined the first digital center in Bulgaria – the place where my journey as a Cloud/DevOps engineer truly began.

At the same time, I took a programming course, and after completing it, I faced a dilemma: whether to continue in infrastructure automation and support or to pursue programming. Ultimately, I chose the DevOps path, following the advice of a manager and a family friend.

Shortly after, I started as a Junior DevOps Engineer. Over the years, I’ve held various roles, gradually moving into team leadership and eventually reaching the position of Head. Throughout this journey, I’ve always aimed to stay close to the technical side of the work, even while being responsible for people and processes.

As a candidate, have you had any strange interviews? What about interviews that impressed you?

I wouldn’t say I’ve had many strange interviews, but one definitely stood out. The interview started directly with a screen-sharing session for live coding—no introduction, no context. I had previously spoken with HR, but the technical part was presented very superficially, and there was no mention that live coding would be part of the process.

As for impressive interviews—one truly stands out.

During a conversation with my future manager, he learned that I had completed a programming course. Instead of just acknowledging it, he shared his own experience—how he had been a Java developer for many years before transitioning into DevOps. In his view, programming requires deep focus on a specific technology, while DevOps forces you to constantly learn new things and think strategically—like playing chess.

That interview not only convinced me to pursue a career in DevOps, but also marked the beginning of a great professional partnership. We ended up working together at three different companies.

What skills and qualities do you look for in a candidate? How can a candidate stand out during the interview?

It depends on the position we’re hiring for.

When it comes to Junior to Mid-level candidates, the main things I value are the motivation to learn, the ability to work in a team, and the willingness to share knowledge. I also expect basic knowledge in scripting, networking, cloud technologies, Terraform, and Kubernetes.

For Senior positions, the expectations are similar in terms of personal qualities, but the technical requirements are higher. Real experience in critical situations is especially valuable – for example, a candidate who has gone through at least one serious downtime. That shows they can remain calm and effective when things go wrong – something that’s key for an experienced engineer.

A candidate can stand out in many ways – for example, by sharing a story about how they handled a challenging situation, by presenting a custom solution they’ve built like a Terraform module or an automation script, or by contributing to open source projects. What matters most is showing passion for what you do and a strong desire to continuously build on your skills.

What questions do you typically ask in technical interviews? Do you have specific tasks or problems that you often use to assess candidates?

Again – it depends on the candidate’s level.

For less experienced engineers, I usually assign a task before the interview, which we then discuss during the interview itself. The goal isn’t so much the solution itself, but to understand how the person thinks. During the discussion, I ask questions related to core technologies – such as Git, CI/CD, Terraform, Kubernetes, monitoring, and logging.

For more experienced candidates, the interview is much more of a conversation – we dive into their previous projects and the solutions they have implemented. We also discuss the core technologies, but in more depth.

How important are good communication skills for a candidate? How do they impact the overall interview?

For me, communication skills are extremely important – regardless of the candidate’s level. In a team, especially in DevOps roles, good communication is what connects people, processes, and technologies. We often work at the intersection of development, QA, and operations, so it’s critical for an engineer to be able to clearly explain ideas, ask the right questions, and share knowledge.

This becomes evident in the interview from the very beginning – not just in how the candidate answers, but also in whether they can explain technical concepts in an understandable way, and how they handle a conversation rather than just a monologue.

How important is cultural fit when making a hiring decision? How do you assess whether a candidate will fit well into the team?

I’d say that cultural fit is probably the most important – and at the same time the hardest to assess – element in the hiring process.

A candidate may be technically excellent, but if they’re difficult to work with, it inevitably has a negative impact on the whole team. In the long run, this leads to increased tension, lower efficiency, and even turnover.

What are the most common mistakes candidates make during an interview? What advice would you give candidates on how to prepare for an interview?

One of the most common mistakes I notice is candidates’ desire to answer everything – even when they’re unsure. In doing so, they often give irrelevant answers, which can have the opposite effect.

Another issue is when candidates respond to questions with just one or two words.

And the most striking mistake, in my opinion, is adding technologies to the CV that they’ve never actually used and have only tried to memorize.

I would advise candidates to focus on a few things when preparing:

• Review the core concepts and technologies, especially if the job description lists specific requirements;

• Think in advance about examples from real experience – successes, difficult situations, mistakes, and what they’ve learned from them.

What advice would you give to candidates who want to improve their technical skills? Are there any resources you would recommend?

I would recommend focusing on practice rather than just theory. 

Use courses from platforms like KodeKloud, Udemy, or YouTube, but it's essential to build your own projects and labs as well.

Share more about the best (or worst) interviews you've conducted.

The best interviews for me are those where the conversation flows naturally – the candidate doesn't just wait for questions but dives into details, shares examples, and talks about the decisions they've made.

One of the most memorable interviews was with a 19-year-old guy who already had five years of experience – he had started working at his uncle's company when he was 14. He impressed me not only with his technical knowledge but also with his approach, confidence, and willingness to learn.

On the other hand, the most challenging interviews are with candidates who answer with "Yes," "No," or "I’ve worked with this," without providing additional context. Even with follow-up questions, the communication remains closed, which makes it almost impossible to assess.

How do you evaluate a candidate during an interview—based solely on their theoretical knowledge, or is their approach to solving a problem/task more important to you? What other factors do you consider when making a decision?

During an interview, I pay attention to how the candidate thinks, how they structure their decisions, and whether they can draw analogies with familiar technologies, even if they haven’t worked directly with the specific one.

I also focus on how they communicate – whether they explain things clearly, if they are open, and how they would fit into the team.

Share a funny story from your experience as an interviewer :)

Once, I interviewed a young candidate who clearly hadn't been through many interviews.

He kept addressing me as "bro" throughout the conversation, and almost after every answer, he would say that it related to the previous one.