15 Must Know Site Reliability Engineer(SRE) Interview Questions for 2023

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Bootcamp

12 min readJul 21, 2023

SRE Professionals often get stuck in their career journey, not with their lack of skill set but with their ability to prepare for Site Reliability Engineer Interview Questions, today we will help you to overcome that.

As the tech industry continues its rapid evolution, the role of Site Reliability Engineers (SREs) has become increasingly vital.

These skilled professionals possess the expertise to ensure the seamless functioning and optimal performance of software systems.

With organizations striving to deliver flawless user experiences, the demand for talented SREs is at an all-time high.

If you’re aspiring to embark on a rewarding career as a Site Reliability Engineer or preparing for an upcoming SRE interview, it’s crucial to be well-prepared for the challenges that lie ahead.

From cutting-edge system design principles to advanced troubleshooting techniques and beyond, we aim to equip you with the knowledge and insights necessary to ace your SRE interview with confidence.

Join us as we unravel the future and delve into the world of Site Reliability Engineer interview questions for 2023.

1. How does an SRE role differ from a traditional operations or software engineering role?

In contrast to traditional operations teams, which focus on running software in production, SREs integrate software engineering practices with operations expertise in order to ensure systems are reliable, scalable, and efficient. This approach to operations enables SREs to develop tools and processes to more effectively manage software and infrastructure. As a result, SREs are able to ensure the reliability and performance of systems while streamlining operations processes.

For example, SREs could automate the deployment of software in production by writing scripts or creating tools that allow developers to quickly deploy software with minimal manual work.

2. Can you explain the concept of error budgets and how they are used in SRE?

An error budget is a way of tracking how much downtime or errors a service can have before it is no longer meeting its Service Level Agreement (SLA). By using error budgets, SRE teams can ensure the reliability of services while still allowing innovation.

In SRE, error budgets are used to:

Set expectations: Error budgets help stakeholders set expectations about downtime or errors acceptable. This can help avoid surprises when a service experiences an outage.
Make decisions: Error budgets can be used to decide whether to release new features or take on new projects. If a service is close to its error budget, it may be a wise idea to pause new development work to focus on improving reliability.
Measure progress: Error budgets can be used to measure progress over time. For example, if a service has a 99.9% uptime SLA, its error budget would be 0.1%. If the service’s error rate is currently 0.05%, it is on track to meet its SLA.

3. What are the key principles of Site Reliability Engineering?

One of the most frequently asked Site Reliability Engineer Interview Questions:

Emphasizing the reliability of systems and services
Implementing automation to minimize manual toil and human error
Using data-driven decision-making to continuously improve system performance
Sharing ownership and responsibilities between development and operations teams
Building scalable and efficient systems that can handle increased traffic and user demand

4. How do you handle incident response and post-mortems?

When an incident occurs, I would follow the following steps:

Prioritize and diagnose the incident to assess its impact on the system and users.
Implement immediate remediation steps to minimize downtime and impact.
Communicate the incident to the relevant stakeholders, including both technical and non-technical teams.
After resolving the incident, conduct a post-mortem analysis to understand its root cause and identify preventive measures.
Share the post-mortem findings with the team, learning from the incident and implementing necessary changes to prevent similar incidents in the future.

5. Tell us about a situation in which you successfully improved the reliability or performance of a system. How did you proceed and what were the results?

In my previous role, I observed recurring performance issues in critical service. In collaboration with the development team, I conducted a detailed performance analysis, identified bottlenecks, and implemented optimizations such as query caching and database indexing. In addition, proactive monitoring and alerting mechanisms were established. The result was a 20% improvement in the system’s response time and a 35% reduction in incidents related to performance degradation.

6. How do you ensure the scalability and performance of a system?

Conducting load testing to simulate heavy traffic and identify bottlenecks.
Optimizing resource allocation and capacity planning to handle increasing demand.
Implementing caching mechanisms to reduce the load on underlying systems.
Horizontal scaling by adding more servers or instances as needed.
Monitoring system metrics and using scaling policies to automatically adjust resources.

7. As an SRE, how do you handle a deployment failure or rollback?

By maintaining a blameless and collaborative culture, we can effectively handle such situations, minimize the impact, and continuously enhance deployment practices.

Implementing automated deployment processes with rollbacks in case of failures.
Detecting deployment failures through comprehensive testing, including unit tests, integration tests, and end-to-end tests.
Using feature flags or canary releases to gradually roll out changes and quickly roll back if necessary.
Having backup and recovery mechanisms in place to mitigate the impact of any failures.

8. How do you manage configuration and infrastructure as code?

Using version control systems and repositories for storing and managing configurations and infrastructure code.
Implementing configuration management tools like Puppet, Ansible, or Chef.
Leveraging Infrastructure as Code (IaC) tools such as Terraform or CloudFormation for provisioning and managing infrastructure resources.
Defining configurations and infrastructure as code allows for consistency, version control, and automation.

9. What tools or technologies do you use or recommend for monitoring and managing systems in an SRE context?

I have experience working with a range of monitoring and management tools, such as Prometheus, Grafana, New Relic, and ELK (Elasticsearch, Logstash, Kibana) stack. These tools provide comprehensive monitoring, alerting, and log analysis capabilities. Additionally, I recommend utilizing infrastructure-as-code (IaC) tools like Terraform or Ansible to enable reproducibility and scalability, and version control systems like Git for tracking changes in configuration and code.

10. How do you ensure the high availability and fault tolerance of a distributed system?

Implementing redundancy and replication across different data centers or availability zones.
Designing systems with fault tolerance in mind, using systems like load balancing, clustering, and failover mechanisms.
Performing regular monitoring and failover testing to ensure high availability.
Using distributed data storage systems with built-in replication and consistency mechanisms.
Implementing automated monitoring and alerting systems to detect and respond to failures quickly.

11. What are some common challenges or obstacles you have faced in implementing SRE principles and how did you overcome them?

There have been various obstacles during my SRE implementation. Some of them are:

Resistance to change: This is one of the biggest challenges in implementing SRE principles. Stakeholders may not understand the value of SRE, or they may be resistant to change. To overcome this challenge, it is important to educate stakeholders about the benefits of SRE, and to involve them in the planning process.
Lack of collaboration between teams: SRE emphasizes shared ownership between development and operations teams. However, it can sometimes be challenging to foster collaboration and break down silos. Encourage cross-functional collaboration by organizing joint meetings, assigning shared responsibilities, and promoting a culture of open communication and collaboration.
Lack of resources: SRE can be a resource-intensive discipline. It requires a team of engineers with a wide range of skills, as well as the right tools and infrastructure. To overcome this challenge, it is important to prioritize SRE initiatives and to make sure that the team has the resources they need.
Balancing stability and innovation: SRE aims to balance the stability and reliability of systems while enabling innovation and frequent deployments. This can be a delicate balance to strike, as too much emphasis on stability may hinder agility, while too much emphasis on innovation may compromise reliability. To overcome this challenge, implement proper risk management and change control processes to assess the impact of changes before implementation, and leverage techniques like feature flags and canary releases to gradually introduce changes and gather feedback.
Legacy systems and technical debt: Dealing with legacy systems and technical debt can pose a significant challenge to implementing SRE principles. Legacy systems often lack automation and monitoring capabilities, making it harder to ensure reliability and scalability. Start by identifying critical areas for improvement and prioritize efforts based on the impact. Gradual refactoring, automation, and adding monitoring tools can help address technical debt over time.
Scaling and managing complexity: As systems grow, scaling and managing complexity becomes more challenging. Implementing proper monitoring, alerting, and observability mechanisms can help identify and address issues quickly. Automation, including infrastructure as code, can facilitate the management of complex systems and reduce human errors. Additionally, investing in continuous learning and knowledge sharing within the team can help in managing complexity effectively.

12. Can you explain the concept of observability and its importance in SRE?

Observability is the ability to understand the state of a system from its external outputs. In the context of SRE, observability is essential for understanding the behavior of complex systems and identifying and resolving problems before they impact users.

Observability goes beyond traditional monitoring, which typically focuses on predefined metrics, by emphasizing the ability to explore and understand system behavior in real time and at scale.

Here are a few reasons why observability is crucial:

Issue detection and troubleshooting: Observability allows SRE teams to detect anomalies and issues in real time. By monitoring key metrics, logs, and traces, teams can identify patterns and pinpoint the root cause of problems. This reduces the time required for troubleshooting and minimizes the impact on users.
Proactive incident prevention: Through effective observability, SRE teams can detect potential issues before they escalate into major incidents. By monitoring system health and performance, teams can identify early warning signs and take proactive measures to prevent system failures or degradation.
Capacity planning and optimization: Observability helps SRE teams understand the resource utilization and performance characteristics of a system. By analyzing metrics and trends, teams can make informed decisions about capacity planning, resource allocation, and system optimization.
Data-driven decision-making: With observability, SRE teams have access to rich data about the system’s behavior and performance. This data can be used to make data-driven decisions, prioritize engineering efforts, and improve the overall reliability of the system.

To achieve observability in SRE, it is important to establish a monitoring and instrumentation strategy that captures relevant data and provides actionable insights. This involves selecting the right monitoring tools, defining relevant metrics, logging important events, and implementing distributed tracing for end-to-end visibility.

13. As an SRE, describe a time when you had to prioritize competing tasks or incidents. How did you decide what to prioritize and how did you handle the situation?

As an SRE, I have encountered many situations where I had to prioritize competing tasks or incidents, and it can be a challenging experience. However, prioritizing is a key skill that is necessary to ensure that the most critical incidents are resolved first, and the team can focus on high-impact tasks.

An example of a time when I had to prioritize competing tasks or incidents was when I was working as an SRE on a production deployment of a new application version. During the deployment, we noticed that our API endpoints were returning an increased error rate, and at the same time, our metrics monitoring alert system informed us of a network outage that was causing a decrease in latency. Simultaneously, our cloud provider announced a change in the infrastructure configuration, and it required downtime that could potentially impact user experience.

To decide what to prioritize, we first evaluated the potential impact of each incident and its level of urgency. We analyzed the error rate and the latency issues, and we concluded that latency was a more significant priority than the error rate, as it was a critical dependency for the application’s data exchange, and it could potentially lead to larger outages down the line.

Regarding the cloud provider’s configuration change, we discussed the need to apply the change despite the potential downtime, and we agreed to perform it one hour from the current time, giving us time to prepare and notify the users proactively.

Once we made these decisions, we directed the team to focus their efforts on addressing the latency issues urgently. We identified the root cause of the issue and resolved the issue by engaging the appropriate team to fix the networking problem quickly and efficiently.

By prioritizing the latency issue, we were able to minimize the impact it had on our users and prevent further damage to the system. This experience taught our team the importance of maintaining situational awareness while prioritizing incidents, and the team responded positively and effectively to the urgent issue.

14. How do you approach capacity planning and resource allocation in an SRE context?

Key considerations that I take into account when approaching capacity planning are the ability to perform rolling deployments with minimal impact, resilience mechanisms to handle risks, and the ability to identify hotspots in the systems and adjust resources where needed.

Here are the key steps that I follow when approaching capacity planning and resource allocation:

Understand the system: The first step in capacity planning is to gain a deep understanding of the system that we are working with — including its architecture, dependencies, and workload pattern. This includes understanding the performance characteristics of the system, such as resource usage, response time, and throughput.
Define capacity and performance goals: Once we understand the system, we need to define the capacity and performance goals that we want to achieve. These goals will vary depending on the use case, but they typically involve ensuring that the system can handle current and future traffic demands while maintaining a high level of service quality (for example, low latency, high availability, or fast response times).
Monitor and measure: To determine whether we are achieving our capacity and performance goals, we need to monitor and measure the key performance indicators (KPIs) of the system — such as CPU usage, memory usage, disk I/O, and network traffic. Monitoring tools such as Prometheus, Grafana, etc., can be used to set up dashboards with graphs that help you visualize the KPIs.
Analyze and optimize: Based on the KPIs, we can then analyze the system’s performance and identify areas where we can optimize resource allocation. This could involve optimizing queries, scaling up instances, or using caching layers. Throughput, results, and other system statistics should be evaluated to find areas for optimization.
Plan for future growth: Once we achieve our capacity and performance goals, we need to plan for future growth to ensure that the system can handle increased traffic loads. This could include scaling up instances, adding more resources, or optimizing further.

15. As an SRE, how can you improve the relationship between operations and IT teams?

Effective communication and working towards achieving shared goals is important. In my current position, as an SRE, I started listening to the teams to understand the potential challenges and created a culture of blameless post-mortem, where we focused on “what has caused the issue” rather than “who has caused the issue” to understand the root cause and implement corrective and preventive measures.

Promoting transparency and information sharing is vital as well. We created knowledge-sharing culture through regular training sessions, workshops, and cross-team collaboration on projects or initiatives.

In addition to the formal communication methods like daily stand-ups, retrospectives, and other regular meetings we also realized the importance of informal communication like team outings, social events, and off-site meetings to create a sense of collaboration.

I have realized that it takes time and effort to build strong relationships between operations and IT teams. By promoting open communication, collaboration, shared goals, and fostering empathy and trust, we can improve the overall relationship between the teams and enhance the efficiency and effectiveness of the organization.

Remember, these are just some of the common site reliability engineer interview questions you may encounter. It’s essential to not only memorize these answers but also understand the concepts behind them.

Conclusion:

Site Reliability Engineer Interview Questions are crucial for aspiring SRE professionals.

Being well-prepared for these questions is essential in the rapidly evolving tech industry where the demand for talented SREs is at an all-time high.

From understanding the differences between Site Reliability Engineer roles and traditional operations or software engineering roles to grasping key principles such as reliability, automation, and data-driven decision-making, a solid foundation is necessary.

Additionally, knowledge of concepts like error budgets, incident response, system scalability, and observability is vital.

Building strong relationships between operations and IT teams through effective communication and collaboration is also important.

By using these Site Reliability Engineer Interview Questions, you can confidently navigate the interview process and excel in your SRE career.

GSDC’s SRE Foundation Certification and SRE Practitioner Certification programs will help you to better understand and prepare for your SRE journey.

Good luck with your interview preparation and stay confident!