Effective Work Sample Exercises for Hiring Infrastructure Engineers

Infrastructure Engineers are the backbone of modern IT operations, responsible for designing, implementing, and maintaining the critical systems that power businesses. Finding the right Infrastructure Engineer requires more than just reviewing resumes and conducting standard interviews. To truly evaluate a candidate's capabilities, practical work samples are essential.

The complexity of infrastructure engineering demands hands-on assessment. While candidates may claim proficiency in cloud architecture, automation, or troubleshooting, their actual skills can only be verified through practical demonstration. Well-designed work samples reveal not just technical knowledge, but problem-solving approaches, attention to detail, and communication abilities.

Infrastructure failures can be catastrophically expensive for organizations. A single misconfiguration or unaddressed vulnerability can lead to downtime costing thousands of dollars per minute. By incorporating realistic work samples into your hiring process, you significantly reduce the risk of bringing on an engineer who looks good on paper but struggles with real-world challenges.

The following exercises are designed to evaluate the core competencies required for Infrastructure Engineers: technical expertise, problem-solving, automation capabilities, and collaboration skills. Each activity simulates real-world scenarios your infrastructure team likely faces, providing valuable insight into how candidates would perform in the actual role.

Activity #1: Cloud Infrastructure Design Challenge

This exercise evaluates a candidate's ability to design scalable, secure, and cost-effective infrastructure solutions. Infrastructure Engineers must balance technical requirements with business constraints, and this activity reveals their architectural thinking and decision-making process.

Directions for the Company:

• Prepare a fictional business case describing a company that needs to migrate a specific application to the cloud (e.g., an e-commerce platform, internal CRM, etc.).
• Include key requirements such as expected traffic patterns, security needs, compliance requirements, and budget constraints.
• Provide a document with the business case and requirements to the candidate 24 hours before the interview.
• During the interview, allow 30 minutes for the candidate to present their design and 15 minutes for questions.
• Ensure the interviewer has sufficient cloud architecture knowledge to evaluate the candidate's design decisions.

Directions for the Candidate:

• Review the provided business case and requirements document.
• Design a cloud infrastructure solution that meets the specified needs, considering scalability, security, reliability, and cost-efficiency.
• Create a simple diagram showing the architecture (using any diagramming tool you prefer).
• Prepare to explain your design choices, including technology selections, security measures, and cost considerations.
• Be ready to discuss alternative approaches and trade-offs you considered.

Feedback Mechanism:

• After the presentation, the interviewer should provide specific feedback on one strength of the design (e.g., "Your approach to auto-scaling based on traffic patterns was well thought out").
• The interviewer should also provide one area for improvement (e.g., "The disaster recovery strategy could be more robust").
• Give the candidate 5-10 minutes to revise their approach to the area identified for improvement, explaining how they would enhance that aspect of the design.

Activity #2: Infrastructure Troubleshooting Simulation

This exercise assesses a candidate's ability to diagnose and resolve complex infrastructure issues under pressure. It reveals their technical knowledge, systematic problem-solving approach, and communication skills during incidents.

Directions for the Company:

• Create a detailed scenario describing a critical infrastructure issue (e.g., application performance degradation, intermittent connectivity problems, or unexpected system behavior).
• Prepare a set of "clues" that can be revealed progressively as the candidate investigates the issue (log excerpts, monitoring screenshots, configuration files).
• Designate an interviewer to play the role of a system user or stakeholder who can provide additional information when asked specific questions.
• Allow 45 minutes for the complete exercise.
• The scenario should have multiple potential causes but one root cause that can be identified through systematic investigation.

Directions for the Candidate:

• You will be presented with an infrastructure issue that needs to be diagnosed and resolved.
• Ask questions to gather more information about the problem and request specific logs or monitoring data as needed.
• Explain your troubleshooting approach step-by-step, including what you're checking and why.
• Identify the most likely root cause of the issue and propose a solution.
• Outline any preventive measures that could be implemented to avoid similar issues in the future.

Feedback Mechanism:

• The interviewer should highlight one effective aspect of the candidate's troubleshooting approach (e.g., "Your methodical elimination of potential causes was very effective").
• The interviewer should also suggest one area for improvement (e.g., "Consider checking network latency earlier in your investigation").
• Ask the candidate to explain how they would incorporate this feedback if they encountered a similar issue in the future.

Activity #3: Infrastructure Automation Task

This exercise evaluates a candidate's ability to automate routine infrastructure tasks, a critical skill for modern Infrastructure Engineers. It demonstrates their scripting abilities, understanding of infrastructure as code principles, and approach to creating maintainable automation solutions.

Directions for the Company:

• Prepare a specific automation task relevant to your environment (e.g., creating a script to provision new virtual machines, automate backup procedures, or implement a monitoring check).
• Provide access to a sandbox environment or specify that the candidate can use pseudocode if a live environment isn't available.
• Specify which automation tools are acceptable (e.g., Bash, PowerShell, Python, Ansible, Terraform).
• Allow 60 minutes for the candidate to complete the task.
• Prepare a rubric that evaluates code functionality, efficiency, error handling, and documentation.

Directions for the Candidate:

• Review the automation task requirements provided.
• Create a script or automation workflow that accomplishes the specified task.
• Include appropriate error handling, logging, and documentation in your solution.
• Be prepared to explain your approach, including any assumptions you made and alternative methods you considered.
• If you don't have access to test your solution in a live environment, include comments explaining how you would validate that your automation works correctly.

Feedback Mechanism:

• The interviewer should provide feedback on one strength of the automation solution (e.g., "Your error handling was comprehensive and would make troubleshooting easier").
• The interviewer should also identify one area for improvement (e.g., "The script could be more modular to improve maintainability").
• Give the candidate 10-15 minutes to refactor the identified portion of their solution based on the feedback.

Activity #4: Infrastructure Migration Planning Exercise

This exercise assesses a candidate's ability to plan complex infrastructure changes while minimizing disruption to business operations. It reveals their project planning skills, risk assessment capabilities, and understanding of dependencies in infrastructure environments.

Directions for the Company:

• Create a scenario describing a significant infrastructure migration (e.g., moving from on-premises to cloud, upgrading a critical system, or consolidating data centers).
• Include details about the current environment, business constraints (like maintenance windows or uptime requirements), and any special considerations.
• Provide the scenario to the candidate 24 hours before the interview.
• During the interview, allow 30 minutes for the candidate to present their migration plan and 15 minutes for questions.

Directions for the Candidate:

• Review the migration scenario provided.
• Develop a comprehensive migration plan that includes:
• Pre-migration assessment and preparation steps
• Migration approach (big bang vs. phased) with justification
• Detailed timeline with key milestones
• Risk assessment and mitigation strategies
• Rollback procedures in case of issues
• Post-migration validation and monitoring
• Create a simple visual representation of your migration timeline and key dependencies.
• Be prepared to explain how your plan minimizes business disruption while ensuring a successful migration.

Feedback Mechanism:

• The interviewer should highlight one particularly effective aspect of the migration plan (e.g., "Your phased approach with validation gates between stages would significantly reduce risk").
• The interviewer should also suggest one area for improvement (e.g., "Consider adding more detail to the post-migration monitoring strategy").
• Ask the candidate to expand on the area identified for improvement, providing additional details or revising their approach.

Frequently Asked Questions

How long should we allocate for each work sample exercise?

For the design and planning exercises (Activities #1 and #4), allocate 45-60 minutes including presentation and feedback. For the troubleshooting simulation (Activity #2), 45 minutes is typically sufficient. The automation task (Activity #3) may require 60-90 minutes depending on complexity. Consider your overall interview timeline and adjust accordingly.

Should we use all four exercises for every candidate?

No, select the exercises most relevant to your specific infrastructure needs. For a cloud-focused role, prioritize the Cloud Infrastructure Design Challenge. If automation is critical, the Infrastructure Automation Task should be included. Choose 1-2 exercises that best align with your priorities.

How technical should the interviewer be for these exercises?

The interviewer should have sufficient technical knowledge to evaluate the candidate's solutions accurately. For specialized areas, consider including a subject matter expert in the interview. The design and migration planning exercises require strategic thinking assessment, while the troubleshooting and automation exercises demand deeper technical expertise.

Can these exercises be conducted remotely?

Yes, all four exercises can be adapted for remote interviews. For the design and planning exercises, candidates can share their screens to present diagrams. For troubleshooting, use screen sharing to provide logs and system information. The automation task can be completed using collaborative coding tools or by having candidates share their screens.

How should we evaluate candidates who use different technologies than our current stack?

Focus on the candidate's approach and reasoning rather than specific technology choices. A strong candidate will explain why they selected particular technologies and demonstrate transferable skills. Consider whether their experience with different technologies might actually bring valuable new perspectives to your team.

Should we provide feedback during the actual interview?

Yes, the feedback mechanism is a crucial part of these exercises. It not only improves the candidate experience but also reveals how receptive they are to constructive criticism—a vital trait for Infrastructure Engineers who must continuously learn and adapt.

Infrastructure Engineers play a critical role in maintaining the technological foundation of your organization. By incorporating these practical work samples into your hiring process, you'll gain deeper insights into candidates' capabilities than traditional interviews alone can provide. These exercises evaluate not just technical knowledge, but the problem-solving abilities, communication skills, and systematic thinking that distinguish exceptional Infrastructure Engineers.

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