Hiring a DevOps Engineer: Top Interview Questions

Before now, development engineers usually worked independently, limiting their knowledge and expertise to coding and testing, while operations engineers directed their energy towards delivery and infrastructure configuration tasks, with little understanding of software development. 

However, there has been a paradigm shift in IT companies following the accelerated advancements in the IT sector and technology. The principle of DevOps functions as a perfect connection between IT development and operations and has become a common approach to software development in recent years.

Functional DevOps teams need people with unique skills. This article focuses on a few DevOps interview questions you can ask and the answers to expect from eligible candidates.

Oh, by the way, we’ve put all of our articles and resources on how to find and hire developers here.

What’s a DevOps Engineer?      

Essentially, a DevOps engineer is an IT professional who collaborates with the system operations team, software developers, and other production IT teams to supervise code releases and deployments. 

The development and operations team uses continuous integration, continuous delivery and testing to provide regular progressive improvements to existing codes. The role requires someone with relevant hard and soft skills to surmount the conventional barriers between software development, QA, testing and IT operations staff and promote a supportive, holistic work setting.

The term “DevOps” is coined from merging two major correlating trends. 

The first was previously called “agile infrastructure” or “agile operations” coming from the application of Agile and Lean principles to operations tasks. 

The second is an elaborate understanding of the importance of collaboration between development and operations teams in every phase of the development lifecycle when building or operating a service.

The following are some of the top questions to ask DevOps engineers during an interview:

Question 1: Why is DevOps necessary?

Candidates can start by describing the current trend in the IT industry. Rather than deploying big sets of features, companies are experimenting with the provision of small features through multiple release trains. 

This means companies have to accelerate the delivery of software products with a low failure rate and provide quick fixes to ensure fast recovery if the new release crashes. The advantages of this approach include better software quality and prompt customer feedback, which will ensure better customer satisfaction.

To achieve this, there is a need to create synergy between the development and operations teams. Development and operations engineers will collaborate all through the product or service lifecycle, from the design phase to deployment. 

DevOps handles this and helps to ensure hitch-free software delivery. Many companies who adopted DevOps have managed to attain performance levels that may have been impractical a few years back. They can now deploy tens or hundreds of codes daily with higher efficiency, security, and stability.

Question 2: What is the difference between DevOps and Agile?

The explanation can take different forms but it boils down to this: 

Agile is a set of values and principles on production methods, such as software development. For instance, if someone has an idea and wants to transform the concept into practical software, they can use Agile values and principles to accomplish that. However, the software might only be functional on a developer’s computer or in a test environment. To move the software easily and fast into production infrastructure in a safe and simple method, they will require DevOps tools and techniques.

The summary is that the Agile software development technique is about software development, while DevOps, on the other hand, handles the development and deployment of the software using the simplest, safest and most reliable method possible.

Question 3: Which do you consider the top tools for DevOps, and how do they work together?

The most common DevOps tools include:

• Git – for version control system
• Selenium – for continuous testing
• Jenkins – for continuous integration
• Nagios – for continuous monitoring
• Puppet, Chef, Ansible – for configuration management and deployment
• Docker – for containerization

Candidates can also mention other tools, but these are the most popular. They can talk about their experience working with some or all the tools for developing and deploying software.

The second part of the question does not have a standard answer. Answers may vary because different companies use DevOps differently. The following is a generic logic that allows for automated operations and easy delivery.

1. Developers create the code and manage the code with version control system tools like Git.
2. Developers forward the source code to the Git repository and commit any changes to the code to the repository.
3. With the Git plugin, Jenkins can take the code from the repository and build it with a tool like Ant or Maven.
4. Configuration management tools like Puppet deploy and provide the testing environment. Jenkins sends the code to the test environment and a tool like Selenium handles the testing.
5. After testing the code, Jenkins forwards it for deployment on the production server, which may be provisioned and managed by a tool such as Puppet.
6. A tool like Nagios handles continuous monitoring upon deployment.
7. The build features are tested using a testing environment provided by Docker.

Question 4: How would you describe your cloud expertise?

A good DevOps engineer should be familiar with cloud-based technologies.

With the world turning to the cloud, there is an increasing demand for DevOps engineers with experience working on cloud-based technologies, including the popular Amazon Web Server (AWS) and RackSpace, Microsoft Azure, Google Elastic Cloud, and OpenStack. 

It’s not just about the number of cloud technologies the candidate has worked with, but also the extent of their experience on previous jobs. A few years back, AWS was probably the only technology most DevOps engineers knew. Nowadays, having experience with AWS is not enough; ask about their experience with S3, EC, Glacier, Redshift, Route53, amidst others.

A good candidate will be excited to describe the number of cloud instances they currently work with and the hours they spend working in the cloud in diverse environments. They can also mention if they have worked on designing, implementing and handled a cloud migration or increased the scale of an environment from small to large in previous jobs.

Question 5: What is version control, and what are the benefits?

This is probably one of the easiest interview questions to ask. 

Version control is a system that monitors and saves alteration to a file or set of files over time so that users can retrieve specific versions later. Version control systems have a central shared repository that allows team members to store changes to a file or set of files.

With Version Control Systems (VCS), every team member can work unrestricted on any file whenever they want. VCS will then allow them to combine all the changes and data into a single version. All the previous versions and variants are carefully arranged in the VCS. When required, users can obtain any version and get a snapshot of the entire project immediately.

Every time someone saves a new version of the project, VCS will ask the person to provide a short description of the changes. Also, other users can see what was modified in the file’s content. A distributed VCS such as Git offers a complete history of the project to every team member. This means that you can use any of the team member’s local Git repository if a breakdown occurs in the central server. The benefits of using VCS include:

• Restore a previous version of a file
• Return the complete project to an earlier version
• Compare and monitor changes
• Pinpoint modifications that might have caused an issue

Question 6: What are the best practices for DevOps implementation?

DevOps implementation is unique across different organizations. Since organizations want to provide software quickly and efficiently, a DevOps engineer must know how to ensure efficient communication, data sharing and collaboration among all stakeholders, including the operations team.

• Every company has specific business goals and objectives. DevOps implementation should align with that and contribute to the change necessary.
• Promote communication and collaboration, particularly between development and operations.
• Automation is essential and should be handled and executed wherever possible in the SDLC stages to ensure the effective operation of DevOps.
• There should be efficient integration among all the tools used in DevOps.
• Without CI and CD practices, DevOps implementation cannot be successful. Therefore, continually integrating the code, rigorous testing, and performing continuous delivery is vital for successful implementation.
• The operations team must ensure that the applications are functioning efficiently at the proper levels. If necessary, they will need to collaborate with development teams to create any tool that will help to infuse proper monitoring functions into the applications.
• Finally, encourage feedback from customers to ensure constant improvements, which is crucial for an efficient process and service delivery.

In conclusion

This list of questions to ask during an interview to hire a DevOps engineer is in no way exhaustive. As a recruiter, you want to ensure that candidates have the required skills and knowledge to perform excellently on the job. In addition to the regular interview questions, you can use technical assessment tests to appraise a candidate’s competence. A DevOps engineer must have detailed knowledge of processes, tools and applicable technology. They must also have a grasp of the products, systems, and data services in place.

It may all feel a little overwhelming, but these interview questions will help you stay on track.