DevOps Engineer Interview: Work Samples & Technical Skill Evaluations

Evaluating DevOps Engineer candidates requires more than just behavioral interviews. The role demands a unique blend of technical expertise, problem-solving abilities, and collaborative skills that are best assessed through practical demonstrations. Work samples and technical skill evaluations provide tangible evidence of a candidate's capabilities in real-world scenarios they'll face on the job.

These practical assessments allow you to:

• Observe how candidates approach complex infrastructure and automation challenges
• Evaluate their technical proficiency with essential DevOps tools and methodologies
• Assess their troubleshooting abilities under realistic conditions
• Gauge their communication skills when explaining technical concepts
• Determine their ability to balance security, performance, and usability requirements

The following work samples and technical evaluations are designed to comprehensively assess the key competencies required for DevOps Engineer success while providing candidates a fair opportunity to demonstrate their skills.

Activity #1: Infrastructure as Code Implementation

This activity evaluates a candidate's ability to implement infrastructure as code solutions, a fundamental skill for modern DevOps practices. It tests their knowledge of IaC tools, cloud resources, and best practices for maintainable infrastructure.

Directions for the Company:

• Provide the candidate with a written prompt describing a simple application architecture (e.g., a web application with a database) that needs to be deployed to a cloud environment.
• Include specific requirements such as high availability, security considerations, and monitoring needs.
• Supply access to a sandbox environment in your preferred cloud platform (AWS, Azure, GCP) or allow them to use a local environment with appropriate tools.
• Allocate 2-3 hours for this exercise, which can be done asynchronously before the interview.
• During the interview, ask the candidate to walk through their solution, explaining their design decisions.

Resources to provide:

• Written architecture requirements
• Access credentials to sandbox environment (if applicable)
• List of available tools/technologies they can use (Terraform, CloudFormation, Pulumi, etc.)
• Documentation links for reference

Directions for the Candidate:

• Create infrastructure as code scripts to deploy the specified architecture.
• Implement best practices for security, scalability, and maintainability.
• Document your solution, including any assumptions made and design decisions.
• Be prepared to explain your approach, including trade-offs considered and how you would improve the solution given more time.
• Your solution should be version-controlled (e.g., in a Git repository) with meaningful commit messages.

Main goal: Demonstrate your ability to translate architectural requirements into infrastructure code that is secure, scalable, and follows DevOps best practices.

Feedback Mechanism:

After the candidate presents their solution, provide two pieces of feedback:

1. Something they did well (e.g., "Your modular approach to the Terraform code will make it very maintainable.")
2. Something they could improve (e.g., "The security group configuration could be more restrictive.")

Allow the candidate 5-10 minutes to explain how they would modify their solution based on the improvement feedback.

Activity #2: CI/CD Pipeline Troubleshooting

This activity assesses a candidate's ability to diagnose and resolve issues in continuous integration and deployment pipelines, a critical skill for ensuring smooth software delivery processes.

Directions for the Company:

• Create a simple application with a deliberately broken CI/CD pipeline (e.g., in GitHub Actions, Jenkins, GitLab CI, etc.).
• Include common issues such as failing tests, configuration errors, or permission problems.
• Provide the candidate with access to the repository and pipeline configuration.
• Allow 45-60 minutes for the troubleshooting session during the interview.

Resources to provide:

• Access to the repository with the application code
• Pipeline configuration files
• Error logs from previous failed pipeline runs
• Documentation for the CI/CD tool being used

Directions for the Candidate:

• Review the provided application and its CI/CD pipeline configuration.
• Identify the issues causing the pipeline to fail.
• Implement fixes to make the pipeline run successfully.
• Document the issues found and the solutions implemented.
• Be prepared to explain your troubleshooting methodology and how you identified each issue.

Main goal: Demonstrate your systematic approach to troubleshooting, your understanding of CI/CD concepts, and your ability to implement effective solutions.

Feedback Mechanism:

After the candidate completes the troubleshooting:

1. Highlight one effective troubleshooting technique they employed.
2. Suggest one area where their approach could be more efficient or thorough.

Give the candidate 5 minutes to explain how they would adjust their troubleshooting approach based on the feedback.

Activity #3: System Performance Optimization Role Play

This role play evaluates a candidate's ability to analyze performance issues and communicate technical solutions to stakeholders, simulating a real scenario they would encounter in the role.

Directions for the Company:

• Create a scenario where a critical application is experiencing performance issues in production.
• Provide metrics, logs, and system architecture diagrams showing the bottlenecks.
• Assign roles to your interview team members (e.g., stressed product manager, technical lead, etc.).
• Send the scenario and supporting materials to the candidate 24 hours before the interview.
• Allocate 30 minutes for the role play during the interview.

Resources to provide:

• System architecture diagram
• Performance metrics and logs showing the issues
• Brief description of the application's purpose and importance
• Recording of an ideal performance analysis discussion (optional)

Directions for the Candidate:

• Review the provided materials to understand the performance issues.
• Prepare an analysis of potential causes and recommended solutions.
• During the role play, you will meet with stakeholders to:
• Explain your diagnosis of the performance issues
• Present your recommended solutions with justifications
• Answer questions and address concerns from stakeholders
• Develop an implementation plan with priorities

Main goal: Demonstrate your technical analysis skills, ability to communicate complex technical concepts clearly, and effectiveness in collaborating with stakeholders under pressure.

Feedback Mechanism:

After the role play:

1. Provide positive feedback on one aspect of their communication or technical analysis.
2. Suggest one way they could improve their stakeholder management or technical recommendations.

Allow the candidate 5 minutes to address how they would incorporate the feedback in a follow-up meeting.

Activity #4: Incident Response Simulation

This simulation tests a candidate's ability to respond to and manage production incidents, a critical responsibility for DevOps engineers who maintain system reliability and uptime.

Directions for the Company:

• Design a realistic incident scenario (e.g., service outage, data breach, infrastructure failure).
• Create a timeline of events that unfold during the simulation.
• Prepare monitoring dashboards, logs, and alerts that the candidate would need to investigate.
• Assign team members to play roles (on-call engineer, security team, etc.).
• Allocate 45-60 minutes for the simulation.

Resources to provide:

• Incident alert details
• Access to monitoring dashboards (real or mocked)
• System architecture documentation
• Runbook templates (if applicable)
• Communication channels for the exercise

Directions for the Candidate:

• You will receive an alert about a critical production incident.
• Follow your incident response process to:
• Assess the severity and impact of the incident
• Investigate the root cause using the provided tools and resources
• Implement immediate mitigation steps
• Communicate status updates to stakeholders
• Document the incident and your response actions
• After resolving the incident, prepare a brief post-mortem analysis.

Main goal: Demonstrate your ability to methodically troubleshoot under pressure, make sound technical decisions, and communicate effectively during a crisis.

Feedback Mechanism:

After the simulation concludes:

1. Highlight one effective action or decision the candidate made during the incident response.
2. Suggest one area where their incident management approach could be improved.

Give the candidate 5-10 minutes to explain how they would incorporate this feedback into their incident response process in the future.

Frequently Asked Questions

How long should each work sample or technical evaluation take?

The Infrastructure as Code implementation should be assigned as a take-home exercise taking 2-3 hours. The CI/CD troubleshooting and Incident Response simulation should each be allocated 45-60 minutes during the interview. The System Performance Optimization role play typically takes 30 minutes. Plan your interview schedule accordingly, and consider splitting these across multiple interview sessions to avoid candidate fatigue.

Should we use our actual production systems for these exercises?

No, never use production systems or sensitive data for interview exercises. Create sandbox environments, mock systems, or simulated scenarios that closely resemble your actual environment but don't expose real data or risk production stability. This protects your company while still providing a realistic assessment.

How technical should the interviewers be for these exercises?

At least one interviewer should have strong technical expertise in DevOps practices to properly evaluate the candidate's solutions. For role plays and simulations, include both technical team members and stakeholders from other departments to assess the candidate's communication skills across different audiences.

How can we make these exercises fair for candidates with experience in different technologies?

Be flexible about the specific technologies used. Focus on evaluating the candidate's approach, problem-solving methodology, and fundamental understanding of DevOps principles rather than expertise with your exact tech stack. Allow candidates to use tools they're familiar with when possible, as a strong DevOps engineer can adapt to new tools quickly.

How do these exercises align with the key competencies for DevOps Engineers?

These exercises directly assess the critical competencies outlined in the DevOps Engineer interview questions, including technical proficiency, problem-solving, collaboration, and communication skills. They provide concrete evidence of a candidate's abilities in these areas beyond what behavioral questions alone can reveal.

Should we compensate candidates for take-home exercises?

For extensive take-home exercises (anything requiring more than 2-3 hours), consider offering compensation for the candidate's time. This demonstrates respect for their expertise and helps ensure high-quality candidates don't drop out of your process due to unreasonable time commitments.

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