10 DevOps SRE Interview Questions and Answers for site reliability engineers

1. What inspired you to specialize in DevOps SRE?

My passion for DevOps SRE was sparked during my time as a software engineer at XYZ Company. I noticed that our development team was experiencing a lot of frustration due to the long and tedious process involved in deploying new features to the production environment.

After conducting research, I discovered that implementing DevOps SRE practices would improve our software delivery process, reduce downtime, and increase efficiency. I proposed this solution to my manager and was given the opportunity to lead the transformation process.

The results were staggering. Our software delivery process became more streamlined, with new features being deployed to production within hours rather than days. Downtime was reduced by 80%, resulting in increased customer satisfaction and a 30% reduction in customer complaints.

Seeing the impact that DevOps SRE had on our team and customers was incredibly rewarding, and it inspired me to specialize in this field. I am passionate about making software delivery smoother, more secure, and more efficient for both development teams and end-users.

2. What kind of experience do you have with automation tools?

Throughout my career, I have gained extensive experience with automation tools. One project that comes to mind is when I worked on a team responsible for managing a large-scale e-commerce website. Our team implemented Ansible as our primary automation tool to automate various tasks such as server configuration and software deployments.

1. Implemented Ansible as the primary automation tool for server configuration and software deployments
2. Reduced configuration time from hours to minutes
3. Improved reliability and consistency of server setups

Also, during my time at a previous company, I was responsible for implementing a CI/CD pipeline using Jenkins. This pipeline was designed to automate the build and deployment process for our software applications. As a result, we were able to significantly reduce the time it took to release new features and bug fixes to our customers.

• Implemented CI/CD pipeline using Jenkins
• Reduced release time from days to hours
• Increased frequency of software releases

Overall, my experience with automation tools has allowed me to streamline processes and improve efficiency in various projects I have worked on.

3. Can you walk me through the incident management process you use to resolve issues?

At my previous company, we followed a structured incident management process to efficiently and effectively resolve any issues that arose. The process involved the following steps:

1. Identify the issue: We relied on monitoring tools to alert us of any issues that occurred. Once an issue was identified, we worked to gather as much information about the issue as possible, including the severity, potential impact, and possible causes.
2. Assign ownership: We assigned ownership of the issue to the appropriate team member or group, depending on the nature of the issue. For example, a networking issue would be assigned to our networking team, while an application issue would be assigned to our development team.
3. Communicate: We ensured that all relevant stakeholders were informed of the issue, including management, other teams, and customers if necessary. Communication was key to keeping everyone in the loop and reducing any potential impact.
4. Diagnose: Once ownership was assigned, the team member or group worked to diagnose the root cause of the issue. This involved reviewing logs, conducting tests, and troubleshooting to identify the source of the problem.
5. Resolve: Once the root cause was identified, we worked to resolve the issue as quickly as possible. This could involve updating software, adjusting networking settings, or implementing other changes to fix the issue.
6. Test: After the issue had been resolved, we conducted thorough testing to ensure that everything was functioning properly. This included running automated tests, manual tests, and even user acceptance testing if necessary.
7. Post-mortem: Finally, we conducted a post-mortem to review the incident and identify any areas for improvement. We looked at what went well, what didn't go well, and what we could do to better handle similar issues in the future.

Throughout this process, we tracked all relevant data and metrics, including time to resolution, frequency of incidents, and customer impact. This allowed us to continually improve our processes and reduce the likelihood of similar issues occurring in the future.

4. What methods do you use to monitor system performance?

As a DevOps SRE, I believe that monitoring system performance is critical to ensuring a smooth running of the system. There are various methods that I use to monitor system performance:

1. I start by setting up a monitoring tool that can continuously check the system's performance, such as Nagios, Zabbix, or Datadog. Depending on the tool, I set up alerts to notify me when the system reaches certain thresholds. For example, I set up an alert to notify me when the CPU usage exceeds 80% or when the disk space drops below 20%.
2. I also use metrics gathering tools such as Grafana or Prometheus to collect performance data and visualize it. These tools allow me to identify bottlenecks in the system, trends in resource usage and, hence, effectively optimize the system.
3. I continuously monitor logs of the running applications to identify errors, performance bottlenecks, or security breaches. For example, I examine Apache or Nginx logs to identify clients with high numbers of requests or those sending requests with large payload sizes.
4. I also conduct stress testing on the system using tools such as Apache JMeter, Gatling, or Locust. The stress tests help me identify performance issues and bottlenecks under high traffic loads. For instance, I conduct a stress test on a payment gateway to determine system response time and, hence, identify the maximum transaction capacity of the system.

Using these methods, I am able to gather data and make informed decisions on optimizing the system's performance. For instance, using Grafana, I discovered that our servers were handling a lot of traffic but not processing a lot of data. This insight helped me optimize the system by adding more application servers to handle the traffic better. As a result, the system's response time decreased by 30%, and we handled one hundred extra requests per second.

5. How do you incorporate feedback from developers to improve the DevOps process?

As a DevOps SRE, incorporating feedback from developers is crucial to continuously improving and refining the DevOps process. The following are steps I take:

1. Regularly schedule feedback sessions: Assess the developers' feedback by scheduling regular meetings to discuss improvements about the DevOps process.
2. Consolidate feedback: Organize and analyze feedback from developers by consolidating their comments and suggestions. This allows for a comprehensive view of the DevOps process, including strengths, weaknesses and areas that require improvement.
3. Prioritize feedback: Determine which feedback provides the greatest potential for improvement and address those items first.
4. Create an action plan: Devise an action plan based on the consolidated feedback to make changes to the DevOps process. During this stage, it is essential to ensure that the objectives, timelines, and expectations of stakeholders are clear.
5. Implement the changes: The changes identified in the action plan should be implemented once they have been agreed with stakeholders.
6. Evaluate the improvements: Review and monitor the improvements put in place, measuring the results of the modified processes. Ensure that the developers are given ample time to adjust to changes.
7. Solicit feedback again: Schedule another round of feedback sessions to allow for continuous improvement.

The results of implementing changes based on feedback from developers encouraged collaboration across departments, removing friction and error, and improving communication. It enabled teams to solve problems quickly, resulting in improved productivity and faster releases of products.

6. Can you describe the deployment process you use for applications?

At my current company, we use a continuous deployment process for our applications. When a developer pushes code to our development branch, our automated build system runs unit tests and builds the application. If the build is successful and all tests pass, the built artifact is pushed to our development environment for further testing and quality assurance.

Once the new feature is thoroughly tested in the development environment, we use a continuous delivery pipeline to ensure it is deployed to the staging environment. We use Kubernetes to manage our containers, and our pipeline deploys the new version of the application to staging using a rolling update strategy. This minimizes downtime while ensuring the new version is not released all at once.

Finally, we have a manual approval process for our production environment. After the changes have been reviewed and tested in the staging environment, we use a simple approval system to promote the changes to production. This ensures that we have a final check before code is released into the wild, reducing the risk of issues in production.

1. Continuous deployment to development environment after successful build and tests
2. Continuous delivery pipeline to deploy to staging environment using rolling update strategy
3. Manual approval process for promotion to production environment

7. How do you ensure high availability of critical systems?

Ensuring high availability of critical systems is paramount for any organization that relies heavily on technology. At my previous company, we employed a number of strategies to guarantee maximum uptime:

1. Designing for redundancy: We made sure that every critical system had at least one backup that could take over in the event of a failure. We also designed our network to have multiple paths to crucial infrastructure, so that if any one component went down, others could maintain service.
2. Automating failover: While designing for redundancy is important, it's equally crucial to ensure that failover actually works when it's needed. To accomplish this, we invested in automation tools that could detect when a system had failed and automatically switch to the backup. This minimized the time for our team to respond, and ensured that our applications stayed online even if an issue occurred outside of normal business hours.
3. Continuous monitoring: We put in place monitoring systems that would alert us immediately in case of a problem. This allowed us to quickly identify and fix issues before they had time to cascade and affect other systems.
4. Regular load testing: To ensure that our systems could handle the demands of real-world traffic, we conducted regular load tests to simulate high traffic volumes. This allowed us to see how our systems performed under stress, and identify areas that needed improvement before they became critical issues.
5. Implementing a Disaster Recovery Plan: We also put in place a comprehensive Disaster Recovery Plan (DRP), which included processes such as data backups, data recovery, and data restoration to ensure that we could recover quickly in case of any unforeseen circumstances like a natural disaster or cyber attack.

By taking these steps, we were able to achieve 99.999% uptime for our critical systems over the past year. This has translated into cost savings as we were able to minimize downtime and keep our customers satisfied with uninterrupted service.

8. What experience do you have with infrastructure as code?

During my time as a DevOps SRE at XYZ Company, I was responsible for managing multiple infrastructure components across multiple environments. To ensure consistency and scalability, I leveraged infrastructure as code practices using tools like Terraform and Ansible.

With Terraform, I was able to create reusable modules for different infrastructure components such as creating multiple instances of an EC2 instance with a specific configuration. This allowed us to spin up new environments with ease and quickly scale up or down based on traffic patterns or business needs. With Ansible, I used it for configuration management across our infrastructure components. I was able to define standard configurations for different components, and then applied those configurations across all instances or environments using Ansible, which also increased efficiency and standardization.

These infrastructure as code tools proved to be crucial in ensuring infrastructure consistency and enabled us to make changes and deploy new infrastructure quickly while minimizing the chance for errors. Additionally, I tracked all infrastructure-related changes in version control, which proved to be invaluable when troubleshooting issues and ensuring accountability.

1. Leveraged infrastructure as code practices using tools like Terraform and Ansible.
2. Created reusable modules for different infrastructure components such as creating multiple instances of an EC2 instance with a specific configuration.
3. Used Ansible for configuration management across infrastructure components for standardization.
4. Used infrastructure as code tools to ensure consistency and enabled fast changes in infrastructure.
5. Tracked all infrastructure-related changes in version control for troubleshooting purposes.

9. How do you approach capacity planning for systems?

When it comes to capacity planning for systems, I typically follow a three-step approach:

1. Collect data: I gather as much data as possible on past system usage, as well as any available projections for future usage (such as growth plans or marketing initiatives). Additionally, I track resource utilization and performance metrics across all layers of the technology stack in order to identify potential bottlenecks.
2. Analyze data: With this data in hand, I use statistical analysis to identify trends and patterns in system usage. This helps me to forecast future resource needs and to identify any areas of the system that may need optimization or additional resources in order to handle anticipated growth.
3. Make adjustments: With my analysis complete, I work with the team to implement any necessary adjustments - this might involve adding new hardware, optimizing code, or reconfiguring systems to better handle anticipated demand. After making these changes, I continue to closely monitor performance, user behavior and measure availability to ensure we are meeting our goals.

An example of the success of this approach came in my previous role, as a Systems Engineer at a large e-commerce platform. By using this method of capacity planning, we were able to forecast an upcoming surge in traffic during the holiday season and made necessary adjustments ahead of time to ensure a seamless experience for users. And as a result, we enjoyed a 40% increase in sales compared to the previous holiday season where we had run into issues with high latency and availability.

10. What role do you see a Site Reliability Engineer playing in collaborating with development teams?

A Site Reliability Engineer plays a crucial role in collaborating with development teams. SREs work with development teams to ensure that the systems developed are optimized for performance, scalability, and reliability.

1. SREs work to design and implement monitoring and alerting systems for production systems. This ensures that developers are aware of any issues that could affect the performance of the system.
2. SREs collaborate with developers to ensure that new code deploys smoothly and seamlessly. By setting up continuous integration and continuous deployment pipelines, SREs help developers reduce the risk of bugs and errors.
3. SREs work closely with developers during the development process to ensure that new features and changes are designed with the needs of the system in mind. This includes reviewing code changes and providing feedback to help optimize performance and reliability.
4. SREs provide valuable insights into system performance, identifying areas where improvements can be made to reduce latency and increase throughput. By working with developers to optimize these areas, SREs help ensure that the system can handle increased traffic without service interruptions.
5. Finally, SREs work with development teams to ensure that the system is secure from potential threats. By implementing security measures such as user authentication and data encryption, SREs help protect the system and ensure that user data remains confidential.

Through close collaboration with development teams, SREs have helped organizations achieve significant improvements in their system reliability and performance. For example, SRE teams at Google have been able to achieve a 10x reduction in the number of incidents affecting their systems, while at the same time increasing the total number of users by over 50%. By working together, SREs and development teams can ensure that systems are designed and built with reliability and scalability in mind, providing users with a seamless and reliable experience.

Conclusion

Congratulations on learning more about common interview questions for DevOps SRE roles in 2023! Your next steps include crafting a captivating cover letter to showcase your skills and experience; our guide on writing a cover letter for SREs can help with that. Also, a well-prepared CV is crucial in impressing potential employers; check out our guide on writing a resume for SREs. Finally, if you're seeking remote SRE positions, be sure to use our job board to find exciting opportunities that match your skills and interests. Don't forget to visit our cover letter guide and our resume guide, and explore our remote SRE job board today!