Site Reliability Engineer Interview Questions with Answers [2025]

SRE Fundamentals

1. What is the primary role of an SRE in an organization?

Site Reliability Engineering (SRE) focuses on ensuring system reliability, scalability, and performance through automation and monitoring. SREs apply software engineering principles to operations, defining SLOs, managing incidents, and optimizing infrastructure. In enterprises, SREs bridge development and operations, using tools like Prometheus for observability to maintain high availability across cloud and on-prem environments.

Explore SRE roles in SRE role in DevOps.

2. Why do companies hire SREs?

• Reliability: Ensures high system uptime.
• Automation: Reduces manual operations.
• Scalability: Handles growing workloads.
• Incident Response: Minimizes downtime impact.
• Observability: Provides deep system insights.
• Compliance: Meets regulatory standards.
• Cost Efficiency: Optimizes resource use.

SREs drive operational excellence in enterprises.

3. When does an SRE intervene in production?

SREs intervene in production during incidents exceeding SLO thresholds, such as error rates or latency spikes. They use runbooks for response, analyze root causes, and implement fixes to restore service.

Interventions ensure minimal disruption in enterprise systems.

4. Where does SRE fit in DevOps culture?

SRE fits in DevOps by promoting shared responsibility for reliability, using tools like GitLab for CI/CD. It emphasizes automation over toil, aligning with enterprise goals for efficient, collaborative operations.

5. Who collaborates with SREs in enterprises?

• DevOps Engineers: Automate deployments.
• Developers: Build reliable code.
• Ops Teams: Manage infrastructure.
• Security Teams: Ensure compliance.
• Product Managers: Define SLOs.
• QA Teams: Validate releases.

Collaboration enhances enterprise reliability.

6. Which SRE principles from Google are widely adopted?

Google's SRE principles, like error budgets and toil reduction, are adopted for balancing innovation with reliability. They guide enterprise practices, ensuring sustainable operations through automation and monitoring.

7. How do SREs define success metrics?

SREs define success with SLOs based on SLIs like availability and latency, tracked with Prometheus. They use error budgets to allow controlled failures, ensuring enterprise systems meet user expectations.

• SLOs: Target reliability levels.
• SLIs: Measurable indicators.
• Error Budgets: Balance innovation.
• Monitoring: Tools like Grafana.
• Alerts: Threshold-based notifications.
• Postmortems: Learn from incidents.
• Automation: Reduce toil.

8. What tools do SREs use for monitoring?

• Prometheus: Time-series metrics.
• Grafana: Visualization dashboards.
• ELK Stack: Log analysis.
• Jaeger: Distributed tracing.
• Alertmanager: Notification handling.
• Datadog: Cloud observability.
• New Relic: Application performance.

Tools provide enterprise observability.

9. Why is error budget important for SREs?

Error budget allows controlled failures, balancing reliability with velocity. Defined as 100% minus SLO, it permits innovation without compromising service levels, guiding enterprise decisions on deployments and features.

• Balance: Innovation vs. stability.
• Measurement: Based on SLOs.
• Decision-Making: Release gates.
• Team Alignment: Shared goals.
• Postmortems: Improve processes.
• Scalability: Enterprise adaptation.

Explore error budgets in SLO alignment.

10. When do SREs conduct postmortems?

SREs conduct postmortems after incidents impacting SLOs, documenting root causes, actions, and improvements. They ensure blameless culture, sharing lessons to prevent recurrence in enterprise systems.

11. Where do SREs document runbooks?

SREs document runbooks in GitLab wikis or Confluence, detailing incident response steps. This ensures quick access during emergencies, enhancing enterprise reliability.

12. Who participates in SRE on-call rotations?

SRE on-call rotations involve engineers from DevOps and operations, scheduled via PagerDuty. They ensure 24/7 coverage, critical for enterprise high-availability systems.

13. Which SRE metric measures system availability?

The availability SLI measures uptime percentage, calculated as (total time - downtime) / total time. It guides SLO setting, ensuring enterprise service reliability.

14. How do SREs reduce toil?

SREs reduce toil by automating repetitive tasks with scripts in GitLab CI/CD. They prioritize high-impact automation, freeing time for innovation in enterprise operations.

automate-task: stage: automate script: - ansible-playbook -i inventory playbook.yml

15. What is the difference between SRE and DevOps?

SRE applies software engineering to operations, focusing on reliability metrics like SLOs, while DevOps emphasizes culture and collaboration. Both overlap in automation, but SRE quantifies reliability for enterprise systems.

• Focus: Reliability vs. collaboration.
• Metrics: SLOs vs. cultural practices.
• Tools: Shared like GitLab.
• Goals: Uptime vs. velocity.
• Roles: Overlapping in enterprises.
• Outcomes: Complementary approaches.

16. Why do SREs use observability tools?

SREs use observability tools like Prometheus to gain insights into system health, detecting issues proactively. They ensure enterprise systems meet SLOs through metrics, logs, and traces.

17. When do SREs declare an incident?

SREs declare an incident when SLOs are breached, such as 99.9% availability dropping. This triggers response, ensuring enterprise service restoration.

Learn about incidents in incident response runbooks.

Monitoring and Observability

18. What is the purpose of SLIs in SRE?

SLIs measure system performance, like latency or error rate, providing data for SLOs. They guide enterprise monitoring, ensuring quantitative reliability assessments.

19. Why are SLOs essential for enterprise systems?

SLOs set reliability targets, like 99.99% uptime, balancing user expectations with innovation. They inform error budgets, driving enterprise decisions on deployments and maintenance.

• Expectations: User satisfaction.
• Budgets: Allow controlled failures.
• Decisions: Release gates.
• Alignment: Team goals.
• Measurement: Track progress.
• Improvement: Post-incident actions.

20. When do error budgets get consumed?

Error budgets get consumed during outages or high error rates, calculated as 100% - SLO. They limit deployments, ensuring enterprise reliability focus.

21. How do SREs set up monitoring dashboards?

SREs set up dashboards with Grafana, integrating Prometheus for metrics like CPU and latency. Configure alerts for SLO breaches, ensuring enterprise visibility into system health.

dashboard: datasource: Prometheus panels: - title: CPU Usage type: graph targets: - expr: rate(node_cpu_seconds_total[5m])

22. What is the role of alerting in SRE?

Alerting notifies teams of SLO violations, configured with Alertmanager for Prometheus. It ensures timely response, minimizing enterprise downtime.

23. Why use distributed tracing in SRE?

Distributed tracing with Jaeger identifies bottlenecks across services, essential for microservices. It provides end-to-end visibility, improving enterprise troubleshooting.

• Visibility: Request flows.
• Debugging: Pinpoint failures.
• Performance: Latency analysis.
• Scalability: Service interactions.
• Compliance: Audit traces.
• Automation: Integrate with pipelines.

24. When to implement chaos engineering?

Implement chaos engineering to test resilience, using tools like Chaos Toolkit in GitLab CI/CD. It's ideal for enterprise systems to simulate failures and validate recovery.

25. Where do SREs store monitoring data?

SREs store monitoring data in Prometheus for metrics, ELK for logs, and Jaeger for traces. Centralize in Grafana for enterprise dashboards and analysis.

Explore storage in observability vs. traditional.

26. Who defines monitoring thresholds?

SREs define monitoring thresholds based on SLOs, using Prometheus Alertmanager. Product teams provide business context, ensuring enterprise alignment with user needs.

27. Which tools support SRE observability?

• Prometheus: Metrics collection.
• Grafana: Dashboard visualization.
• ELK Stack: Log management.
• Jaeger: Tracing services.
• Alertmanager: Notification routing.
• Datadog: Unified observability.

Tools provide comprehensive enterprise insights.

28. How do you configure alerts for SLO breaches?

Configure alerts with Prometheus rules for SLO breaches, defining queries like error_rate > 0.01. Route via Alertmanager to Slack or PagerDuty, ensuring enterprise rapid response.

groups: - name: slo-alerts rules: - alert: HighErrorRate expr: rate(http_errors[5m]) > 0.01

29. What is the impact of poor observability?

Poor observability delays incident detection, increasing downtime. It affects enterprise MTTR, tested in certifications for SRE tools and practices.

30. Why use SLOs for capacity planning?

SLOs guide capacity planning by identifying reliability gaps, using metrics like latency. They ensure enterprise resources align with user expectations, preventing over-provisioning.

31. When to review monitoring configurations?

• Post-Incident: Update based on lessons.
• Quarterly: Align with SLO changes.
• Scaling: Adjust for new loads.
• Tool Updates: Verify compatibility.
• Compliance: Meet regulatory needs.
• Team Feedback: Improve usability.

Reviews maintain enterprise observability.

32. How do you implement distributed tracing?

Implement distributed tracing with Jaeger, instrumenting code with OpenTelemetry. Integrate with GitLab CI/CD for trace collection, ensuring enterprise end-to-end visibility.

33. What is the role of SLOs in postmortems?

SLOs in postmortems quantify incident impact, guiding improvements. They ensure blameless analysis, enhancing enterprise reliability through actionable insights.

Explore SLOs in SLO alignment.

Incident Management and Response

34. What steps follow an incident declaration?

After declaration, activate incident response with runbooks, notify on-call via PagerDuty. Triage, isolate, and fix issues, documenting for postmortems to improve enterprise processes.

35. Why conduct blameless postmortems?

Blameless postmortems encourage open discussion, focusing on processes rather than individuals. They identify root causes, prevent recurrence, and foster learning in enterprise teams.

• Learning: Systemic improvements.
• Culture: Encourages reporting.
• Compliance: Documented actions.
• Efficiency: Reduces future incidents.
• Teamwork: Shared responsibility.
• Scalability: Applies to large teams.

36. When to escalate an incident?

Escalate when initial responders can't resolve within MTTR, or impact grows. Use PagerDuty for tiered alerts, ensuring enterprise escalation paths are clear.

37. How do you create effective runbooks?

Create runbooks in GitLab wikis with step-by-step procedures, including commands and escalation contacts. Version with Git, test periodically, ensuring enterprise quick response during incidents.

# Incident Runbook ## Step 1: Isolate kubectl scale deployment app --replicas=0

38. What is the role of on-call rotations?

On-call rotations ensure 24/7 coverage, scheduled via PagerDuty. They distribute workload, preventing burnout, and are critical for enterprise high-availability systems.

39. Why use incident command systems?

Incident command systems coordinate responses, assigning roles like incident commander. They ensure structured communication, reducing confusion in enterprise incidents.

40. When to declare a major incident?

Declare a major incident when multiple services are affected or SLOs are severely breached. This activates full response teams, ensuring enterprise-wide coordination.

41. How do you measure incident response effectiveness?

Measure with MTTR, using metrics from PagerDuty. Analyze postmortems for improvements, ensuring enterprise response times meet SLOs.

Explore MTTR in incident response runbooks.

42. What is the impact of toil on SRE teams?

Toil, manual repetitive tasks, reduces productivity. SREs automate toil to focus on innovation, ensuring enterprise efficiency and scalability.

43. Why prioritize incident prioritization?

Prioritization focuses on high-impact incidents, using severity levels. It ensures enterprise resources address critical issues first, minimizing overall downtime.

44. How do you document incidents?

Document incidents in postmortems with root cause, actions, and lessons. Use GitLab issues for tracking, ensuring enterprise knowledge sharing.

45. What is the role of communication in incidents?

Communication keeps stakeholders informed, using Slack or email. It reduces confusion, ensuring enterprise coordination during crises.

Advanced SRE Practices

46. What is the purpose of chaos engineering?

Chaos engineering tests system resilience by injecting failures, using tools like Chaos Monkey. It ensures enterprise systems handle disruptions, improving reliability.

47. Why use error budgets in SRE?

• Balance: Allows innovation.
• Measurement: Quantifies reliability.
• Decisions: Gates releases.
• Alignment: Team goals.
• Improvement: Drives automation.
• Compliance: Audit metrics.

Error budgets guide enterprise reliability.

48. When to implement capacity planning?

Implement capacity planning during scaling, using Prometheus metrics. It predicts resource needs, ensuring enterprise systems handle growth without outages.

49. How do SREs automate toil?

Automate toil with scripts in GitLab CI/CD, like Ansible playbooks for deployments. Identify repetitive tasks, code solutions, ensuring enterprise operational efficiency.

automate-deploy: stage: deploy script: - ansible-playbook -i inventory deploy.yml

50. What is the role of SRE in cloud migrations?

SRE ensures reliability during cloud migrations, defining SLOs and monitoring with Prometheus. They automate deployments with Terraform, minimizing risks in enterprise transitions.

51. Why use SLOs for vendor management?

SLOs define service levels with vendors, ensuring accountability. They guide contracts, ensuring enterprise compliance and performance expectations.

52. When to review SRE runbooks?

Review runbooks post-incident or quarterly, updating for new tools. This ensures enterprise response readiness and accuracy.

53. How do you measure SRE team effectiveness?

Measure SRE effectiveness with MTTR, toil percentage, and SLO achievement. Use surveys for team satisfaction, ensuring enterprise operational health.

• MTTR: Incident resolution time.
• Toil: Manual task percentage.
• SLOs: Reliability targets.
• Deployment Frequency: Release speed.
• Team Surveys: Morale assessment.
• Automation Rate: Task efficiency.

54. What is the impact of SRE on business outcomes?

SRE improves uptime, reducing revenue loss from outages. It accelerates deployments, boosting innovation, and ensures compliance, driving enterprise business success.

55. Why prioritize SRE observability?

Observability provides insights into system behavior, using metrics, logs, and traces. It enables proactive fixes, ensuring enterprise system reliability.

56. When to use SRE runbooks?

Use runbooks during incidents for structured response, detailing steps and contacts. They reduce resolution time, ensuring enterprise continuity.

57. How do you balance reliability and innovation?

Balance with error budgets, allowing failures within SLOs. This permits innovation while maintaining reliability, key for enterprise agility.

Explore balance in multi-cloud DevOps.

58. What is the role of SRE in incident prevention?

SRE prevents incidents through proactive monitoring and automation, using Prometheus for alerts. They analyze trends, reducing MTTR in enterprise systems.

59. Why document SRE processes?

Document processes in runbooks and wikis for knowledge sharing. It ensures consistency, reduces toil, and supports enterprise onboarding and compliance.

60. How do SREs handle on-call fatigue?

Handle on-call fatigue with rotations, time off, and automation. Use PagerDuty for scheduling, ensuring enterprise coverage without burnout.

61. What tools support SRE incident response?

• PagerDuty: On-call scheduling.
• Slack: Team communication.
• PagerTree: Incident management.
• VictorOps: Alert routing.
• Opsgenie: Escalation workflows.
• Runbooks: Step-by-step guides.

Tools streamline enterprise responses.

62. Why use blameless postmortems?

Blameless postmortems focus on processes, encouraging open discussion. They identify systemic issues, improving enterprise reliability and team morale.

63. When to escalate incidents?

Escalate incidents when MTTR exceeds thresholds or impact grows. Use PagerDuty for tiered alerts, ensuring enterprise coordination.

64. How do you calculate error budgets?

Calculate error budgets as (1 - SLO) * time period, like 0.01% of 30 days. Monitor with Prometheus, ensuring enterprise balance between reliability and velocity.

error_budget = (1 - 0.999) * 2592000 # 30 days in seconds

65. What is the impact of toil on SRE?

Toil reduces innovation time, manual tasks consuming resources. SREs automate toil, ensuring enterprise focus on high-value work.

Learn about toil in over-automation pitfalls.

66. Where do SREs store incident data?

SREs store incident data in PagerDuty or GitLab issues, with logs in ELK. This ensures enterprise traceability and analysis for improvements.

67. Who participates in incident reviews?

Incident reviews involve SREs, developers, and managers, using postmortems. This ensures enterprise learning and process refinement.

Reviews foster blameless culture.

68. Which practices reduce incident frequency?

• Automation: Minimize manual errors.
• Monitoring: Proactive detection.
• Testing: Comprehensive validation.
• Postmortems: Root cause analysis.
• SLOs: Reliability targets.
• Runbooks: Standardized response.

Practices enhance enterprise reliability.

69. How do you implement incident command?

Implement incident command with roles like commander and communicator, using Slack for coordination. Document in runbooks, ensuring enterprise structured response.

# Incident Command Commander: Leads response Communicator: Updates stakeholders

70. What is the role of MTTR in SRE?

MTTR measures time to resolve incidents, optimized with runbooks and monitoring. It guides enterprise improvements, reducing downtime impact.

Advanced SRE Practices

71. What is chaos engineering in SRE?

Chaos engineering tests system resilience by injecting failures, using tools like Chaos Toolkit. It ensures enterprise systems handle disruptions, improving reliability.

72. Why use capacity planning in SRE?

Capacity planning predicts resource needs using metrics like CPU usage. It prevents outages, ensuring enterprise scalability and cost efficiency.

73. When to automate SRE tasks?

Automate SRE tasks when toil exceeds 50%, using scripts in GitLab CI/CD. This frees time for innovation in enterprise operations.

• Toil Threshold: Manual task limits.
• Impact: High-repetition tasks.
• ROI: Time savings.
• Compliance: Automated audits.
• Scalability: Handle growth.
• Testing: Validate automation.

Explore automation in immutable infrastructure.

74. How do SREs collaborate with developers?

SREs collaborate with developers through shared SLOs, code reviews, and joint postmortems. They provide feedback on reliability, ensuring enterprise code meets performance standards.

75. What is the role of SRE in cloud migrations?

SRE ensures reliability during migrations, defining SLOs and monitoring with Prometheus. They automate with Terraform, minimizing risks in enterprise transitions.

76. Why define SLAs for external partners?

SLAs define expectations with partners, ensuring accountability. They guide contracts, maintaining enterprise service levels and compliance.

77. When to review SRE runbooks?

Review runbooks post-incident or quarterly, updating for new tools. This ensures enterprise response readiness and accuracy.

• Post-Incident: Incorporate lessons.
• Quarterly: Align with changes.
• Tool Updates: Verify compatibility.
• Team Feedback: Improve usability.
• Compliance: Meet regulations.
• Testing: Simulate scenarios.
• Versioning: Track revisions.

78. How do you measure SRE team impact?

Measure impact with MTTR, toil reduction, and SLO achievement. Use surveys for satisfaction, ensuring enterprise operational health and productivity.

79. What is the impact of SRE on business?

SRE improves uptime, reducing revenue loss. It accelerates deployments, boosting innovation, and ensures compliance, driving enterprise success.

80. Why prioritize SRE observability?

Observability provides insights into system behavior, using metrics, logs, and traces. It enables proactive fixes, ensuring enterprise system reliability and performance.

81. When to use SRE runbooks?

Use runbooks during incidents for structured response, detailing steps and contacts. They reduce resolution time, ensuring enterprise continuity and efficiency.

Runbooks are tested in simulations.

82. How do you balance reliability and velocity?

Balance with error budgets, allowing failures within SLOs. This permits innovation while maintaining reliability, key for enterprise agility and certifications.

Explore balance in multi-cloud DevOps.

83. What is SRE's role in incident prevention?

SRE prevents incidents through proactive monitoring with Prometheus and automation. They analyze trends, reducing MTTR in enterprise systems for sustained reliability.

84. Why document SRE processes?

Document processes in runbooks and wikis for knowledge sharing. It ensures consistency, reduces toil, and supports enterprise onboarding and compliance requirements.

85. How do SREs handle on-call fatigue?

Handle on-call fatigue with rotations, time off, and automation. Use PagerDuty for scheduling, ensuring enterprise coverage without burnout, maintaining team morale.

Fatigue management supports long-term reliability.

86. What tools support SRE incident response?

• PagerDuty: On-call scheduling.
• Slack: Team communication.
• PagerTree: Incident management.
• VictorOps: Alert routing.
• Opsgenie: Escalation workflows.
• Runbooks: Step-by-step guides.
• Incident Commander: Role assignment.

Tools streamline enterprise responses.

87. Why use blameless postmortems?

Blameless postmortems focus on processes, encouraging open discussion. They identify systemic issues, improving enterprise reliability and team morale through learning.

88. When to escalate incidents?

Escalate incidents when MTTR exceeds thresholds or impact grows. Use PagerDuty for tiered alerts, ensuring enterprise coordination and rapid resolution.

89. How do you calculate MTTR?

Calculate MTTR as total downtime divided by incidents, tracked with PagerDuty. Analyze trends to improve response, ensuring enterprise efficiency.

mttr = total_downtime / number_of_incidents

90. What is the role of incident command?

Incident command coordinates responses with roles like commander and communicator. It ensures structured communication, reducing confusion in enterprise incidents.

Learn about command in incident runbooks.

Cloud and Integration Scenarios

91. What is SRE's role in cloud migrations?

SRE ensures reliability during migrations, defining SLOs and monitoring with Prometheus. They automate with Terraform, minimizing risks in enterprise transitions to cloud environments.

92. Why use Kubernetes in SRE?

• Orchestration: Manages containers.
• Scalability: Auto-scales workloads.
• Resilience: Self-healing features.
• Observability: Integrates Prometheus.
• Compliance: Security policies.
• Automation: GitLab CI/CD.

Kubernetes enhances enterprise SRE practices.

93. When to implement multi-cloud SRE?

Implement multi-cloud SRE for vendor diversity, using tools like Terraform for IaC. It ensures enterprise resilience against outages.

Multi-cloud reduces single-vendor risks.

94. How do you monitor cloud costs as SRE?

Monitor cloud costs with Prometheus metrics for resource usage, setting budgets in AWS Billing. Automate alerts, ensuring enterprise cost optimization.

95. What is the role of SRE in hybrid cloud?

SRE in hybrid cloud ensures consistency across on-prem and cloud, using unified monitoring. They automate with GitLab, ensuring enterprise reliability.

96. Why use Terraform for SRE?

Terraform automates infrastructure, ensuring reproducible environments. SREs use it in pipelines for compliance and scalability in enterprise cloud setups.

97. When to use SRE for serverless?

Use SRE for serverless to monitor functions with Prometheus, defining SLOs for latency. It ensures enterprise scalability without infrastructure management.

Explore serverless in event-driven architectures.

98. How do you integrate SRE with DevSecOps?

Integrate SRE with DevSecOps by adding security scans in pipelines, using GitLab SAST. Ensure SLOs include security metrics, ensuring enterprise compliance.

99. What is the impact of SRE on cloud costs?

SRE reduces cloud costs through capacity planning and automation, optimizing resources. They use metrics to right-size instances, ensuring enterprise efficiency.

100. Why prioritize SRE in cloud-native?

Prioritize SRE in cloud-native for reliability in distributed systems, using Kubernetes for orchestration. It ensures enterprise resilience and performance.

101. How do SREs handle cloud outages?

SREs handle cloud outages with multi-region deployments and failover strategies. Monitor with Prometheus, automate recovery with Terraform, ensuring enterprise uptime.

multi-region: stage: deploy script: - terraform apply -var="region=us-west-2"

102. What is the role of SRE in observability?

SREs use observability to detect issues early, integrating Prometheus and Grafana. It ensures enterprise system health and proactive management.

103. Why use SRE for edge computing?

SRE for edge computing ensures low-latency reliability, using distributed monitoring. It supports IoT scalability in enterprise environments.