10 Infrastructure as Code (IaC) Interview Questions and Answers for devops engineers

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1. What experience do you have with IaC tools such as Terraform, CloudFormation, or Ansible?

I have extensive experience using Terraform to manage infrastructure as code for a Fortune 500 company's AWS environment, resulting in a 40% reduction in infrastructure deployment time. Specifically, I utilized Terraform to automate the provisioning of EC2 instances, Elastic Load Balancers, and RDS databases, among other resources. This allowed our DevOps team to focus on more strategic initiatives rather than manual infrastructure management.

  1. I have also worked with CloudFormation to provision infrastructure in an Azure environment, such as Azure Virtual Machines, Azure SQL Databases, and Azure Storage accounts.
  2. Furthermore, I have used Ansible to automate configuration management of on-premise servers in a Linux environment, resulting in a 50% reduction in deployment time and a 30% cost savings on IT resources. I developed custom playbooks to standardize configurations across servers and to automate software installations and updates.
  3. In addition to these tools, I have experience with GitLab CI/CD pipelines for automating the deployment of infrastructure changes, enabling continuous delivery and deployment in a safe and repeatable fashion.

Overall, my experience with IaC tools has allowed me to significantly improve infrastructure efficiency, reduce deployment time, and automate configuration management, resulting in significant cost savings and increased productivity.

2. What are the benefits and drawbacks of using IaC?

Benefits of using IaC:

  1. Consistency: Using IaC ensures that the infrastructure is consistent across all environments, which in turn reduces errors and increases productivity. For example, implementing IaC led to a 50% reduction in configuration errors at our previous company.
  2. Scalability: With IaC, you can easily scale your infrastructure up or down as per your needs. For instance, we were able to scale our infrastructure by 200% in just 30 minutes using Terraform, a popular IaC tool.
  3. Efficiency: IaC allows for rapid provisioning of infrastructure, reducing time to market for new products/features. At my previous job, we were able to reduce the time taken to provision a new server by 70%.
  4. Reduced Costs: By using IaC, companies can reduce infrastructure costs by only provisioning what is needed, and by automating repetitive tasks. For example, we were able to reduce our AWS bills by 40% by making use of Autoscaling groups and Lambda functions.

Drawbacks of using IaC:

  • Learning Curve: While the benefits of IaC are numerous, it requires a significant learning curve to become proficient with the technology. However, once the initial investment is made, the benefits far outweigh the costs.
  • Cost of Ownership: Implementing IaC can have a higher initial cost of ownership, both in terms of infrastructure and personnel. However, these costs can be offset by the benefits of reduced errors and increased productivity over time.
  • Complexity: IaC can be complex, especially for larger, more complex infrastructures, which may require more advanced knowledge of the underlying technology. However, tooling and documentation can help mitigate this issue.
  • Version Control: IaC requires proper version control in order to manage changes to the infrastructure. Failure to do so can lead to inconsistencies and potentially catastrophic errors. However, this can be easily mitigated by implementing proper version control tools and processes.

3. How do you ensure the security of sensitive data when using IaC?

When working with sensitive data in IaC, security is of utmost importance. Firstly, I make sure to use encryption on all sensitive data stored in the code repository such as passwords, private keys, and certificates. This ensures that even if someone gets access to the repository, they will not be able to read the sensitive data.

Secondly, I ensure that all users who have access to the IaC code and infrastructure follow the principle of least privilege. This means that they only have access to the resources they need and nothing more. By following this principle, we limit the chances of someone accessing sensitive data they should not have access to.

Thirdly, I enforce strict access controls and logging mechanisms within the infrastructure using tools like AWS CloudTrail and Azure Security Center. By keeping track of all access attempts and changes, we have the ability to identify and respond to any potential security threats.

Finally, I continuously monitor the infrastructure for any security threats or vulnerabilities using tools like Chef and Puppet. By conducting regular security audits and vulnerability scanning, we can quickly identify and eliminate any potential security risks before they cause any harm to the infrastructure or sensitive data.

  1. Encryption of sensitive data stored in code repositories;
  2. Enforcing the principle of least privilege;
  3. Strict access controls and logging mechanisms;
  4. Continuous monitoring and regular security audits and vulnerability scanning.

4. Can you give an example of a particularly challenging infrastructure deployment you assisted with using IaC?

Yes, at my previous company we were tasked with migrating a large monolithic application to a microservices architecture on AWS. This was a challenging deployment because the application had been built over several years and was tightly coupled to the underlying infrastructure.

  1. First, we created a Terraform configuration which defined our new architecture. This included setting up VPCs, subnets, security groups and EC2 instances.
  2. We then used Ansible to deploy our microservices to the EC2 instances. We decided to use Ansible because it allowed us to automate not only the deployment of the code but also the configuration of the underlying infrastructure.
  3. We also used Docker to containerize our application which made it easier to deploy and maintain.
  4. One of the biggest challenges we faced was how to migrate our data from the monolithic application to the new microservices infrastructure. We decided to use AWS Database Migration Service to move our data from our old Oracle database to an Aurora PostgreSQL database.
  5. The deployment took longer than expected, but we were eventually able to successfully migrate the application to the microservices architecture. We were able to reduce our infrastructure costs by 50% and saw a 40% improvement in our application's performance.

Overall, this deployment was a great learning experience for me and I was able to gain valuable experience using IaC tools like Terraform, Ansible, Docker, and AWS Database Migration Service.

5. What type of testing do you recommend for IaC?

When it comes to testing IaC, I recommend using automated testing approaches such as unit testing and integration testing. These methods allow for quick and efficient testing of the code base, and they can help ensure the code is functioning properly and works as intended.

  1. Unit testing: This type of testing involves testing individual modules or functions of the code base. It can be helpful in catching issues early in the development process and isolating specific issues that need to be addressed. For example, we can use tools like Pytest, Mocha, or Jest to test individual functions in IaC templates.

  2. Integration testing: This type of testing involves testing how the different modules or functions of the code base work together. It is useful in catching issues that arise from interactions between different parts of the code, and can help ensure that the IaC templates work as expected when integrated with other systems. Using tools like Terratest, Robot Framework, or Cypress can be helpful for integration testing in IaC.

Using automated testing methods like these can help us catch issues early in the development process and ensure that our infrastructure is reliable and consistent. For instance, since our team started using unit testing and integration testing, we've seen a decrease in the number of bugs and issues that make it to production by over 30%. Additionally, our team's turnaround times for fixing issues has also decreased by 50% due to the early detection of problems.

6. What monitoring and logging solutions have you used with IaC?

During my time as a DevOps Engineer at XYZ Company, I used a combination of monitoring and logging solutions to ensure that our IaC infrastructure was running smoothly. One of the tools we used was CloudWatch, which allowed us to monitor and log different resources within AWS.

  1. CloudWatch Metrics and Alarms:
  2. We set up CloudWatch metrics and alarms for our EC2 instances and other resources to notify us when certain thresholds were passed. For example, we set up an alarm to notify us if the CPU utilization of any EC2 instance exceeded 80% for more than 5 minutes. This helped us catch issues early and prevent downtime.

  3. CloudTrail:
  4. We also used CloudTrail to log all API calls made within our AWS environment. This allowed us to track changes made to our IaC infrastructure and troubleshoot any issues that arose. For example, we were able to identify a misconfigured security group that was blocking traffic to an application after reviewing CloudTrail logs.

  5. Syslog and Elasticsearch:
  6. In addition to AWS-specific tools, we also used Syslog and Elasticsearch to collect and store logs from our infrastructure. This allowed us to easily search and analyze logs from our different resources in one central location. For example, we were able to identify a recurring issue with a service that was causing occasional drops in traffic after reviewing logs from our load balancers, EC2 instances, and databases in Elasticsearch.

Overall, our monitoring and logging solutions provided us with valuable insights into our IaC infrastructure and helped us proactively identify and resolve issues before they had a chance to impact our users.

7. How do you handle version control with IaC?

Version control is a crucial aspect of infrastructure as code. As a DevOps Engineer, I use Git for version control in IaC. Whenever I make changes to the code, I create a new branch and commit the changes. Once the changes are fully tested and verified, I merge the branch to the main branch (master), and the infrastructure is updated accordingly.

To maintain a history of changes, I use tags to mark significant milestones, such as releases or updates. This provides an audit trail that enables me to trace changes back to a specific point in time.

A key benefit of using Git for IaC version control is that it enables me to collaborate with other team members. We can work on the same codebase simultaneously, merge changes, and resolve conflicts. This makes the development process more efficient and effective.

I have used this approach in previous roles, and it has proven to be effective. For example, at my previous company, we used Git for version control in IaC, and it helped us reduce deployment times by 50%. Additionally, we were able to release new features more frequently, allowing us to stay ahead of our competitors.

8. What steps do you take to ensure infrastructure changes are documented and communicated effectively?

As someone who values efficient communication and documentation, I take the following steps to ensure infrastructure changes are properly documented and communicated:

  1. Create a central source of truth for infrastructure documentation
  2. By having a central location for infrastructure documentation, such as a Wiki or Google Drive folder, team members can easily access the latest updates and changes. This reduces confusion and ensures everyone is working from the same page.

  3. Update documentation in real-time
  4. I make sure that documentation is updated concurrently with infrastructure changes. This ensures that the documentation is always up-to-date and correctly reflects the current state of the infrastructure.

  5. Ensure documentation is understandable for anyone on the team
  6. As infrastructure can be complex, I make sure that the documentation is written in a clear and concise way; using simple language and avoiding jargon or highly technical terms. This ensures that anyone on the team can understand the documentation.

  7. Communicate changes via multiple channels
  8. I communicate infrastructure changes via multiple channels, such as Slack or Email, and also make sure that the information is shared in team meetings. This ensures that everyone is aware of the changes and can ask any relevant questions.

  9. Provide context and reasoning for changes
  10. Infrastructure changes can sometimes be unexpected and cause confusion. To reduce this, I make sure I provide context and reasoning for the changes in the documentation and communication. This helps the team better understand why the changes are necessary.

  11. Track the impact of changes
  12. To ensure that changes are having the desired effect and to identify any issues, I track and document the impact of changes. This helps the team to evaluate the effectiveness of the change and to identify when further changes may be needed.

By taking these steps, I ensure that infrastructure changes are properly documented and communicated effectively, reducing confusion and ensuring everyone on the team is aware of the latest updates and changes.

9. Have you integrated IaC into continuous integration and continuous delivery (CI/CD) pipelines before?

Yes, I have integrated Infrastructure as Code (IaC) into Continuous Integration and Continuous Delivery (CI/CD) pipelines in my previous work experience as a DevOps Engineer at XYZ Company.

  1. Firstly, I ensured that all infrastructure configurations were stored in code using tools such as Terraform and Ansible.
  2. Then, I integrated this code into our CI/CD pipeline using Jenkins.
  3. During the pipeline, each change to the infrastructure code was automatically tested using tools such as Terratest and Test Kitchen to ensure that the changes did not cause any issues or unexpected behavior.
  4. If the tests passed, the changes were automatically deployed to our staging environment for further testing and validation by the Quality Assurance team.
  5. After testing, the updates were automatically deployed to production, which significantly reduced our deployment time and resulted in a more reliable and consistent infrastructure.
  6. Furthermore, by implementing IaC into our CI/CD pipeline, we were able to easily roll back infrastructure updates if any unexpected issues arose, without having to spend too much time diagnosing the problem.

The implementation of IaC into our CI/CD pipeline resulted in a 50% reduction in deployment time and a 25% reduction in the number of infrastructure-related incidents reported, which greatly improved the overall stability and availability of our applications.

10. How do you approach troubleshooting when an IaC deployment fails?

When it comes to troubleshooting an IaC deployment failure, my approach consists of the following steps:

  1. Reviewing the logs and error messages: When an IaC deployment fails, the first thing I do is check the logs and error messages to understand what went wrong. This helps me to identify the root cause of the problem and focus on the specific area where the error occurred.

  2. Testing the deployment: After identifying the root cause of the issue, I test the deployment again to see if the changes I made have resolved the problem. I use a staging environment to ensure that the code is working as expected before pushing it to production.

  3. Identifying potential problems: Rather than just fixing the current issue, I also look for potential problems that might arise in the future. Through a careful analysis of the deployment, I can often identify issues before they happen and prevent them from causing problems.

  4. Documenting the fixes: Once I've resolved the issue, I document the steps I took to fix the problem. This helps in the future if the same issue arises again or if someone else must troubleshoot the deployment.

Using this approach, I was able to troubleshoot a recent IaC deployment that had failed due to an issue with the network connection. By reviewing the logs, I found that the connection to the server was not established properly, and I fixed the problem by updating the network configuration. I then tested the deployment in the staging environment before pushing it to production, ensuring that the problem was fully resolved before launch.


Congratulations on completing our list of top 10 Infrastructure as Code (IaC) interview questions and answers for 2023. Now it's time to take the next steps towards landing your dream remote DevOps Engineer job! Don't forget to write an impressive cover letter by checking out our guide on writing a cover letter, and to prepare your CV using our guide on writing a resume for DevOps Engineers. Utilize Remote Rocketship's job board to find the best remote DevOps Engineer opportunities. Check it out now at Remoterocketship.com/jobs/devops-and-production-engineering and take the next step towards a fulfilling and remote career!

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