Finastra India Site Reliability Engineer Interview: Rounds, Questions and Preparation

What the job involves

Site Reliability Engineers (SREs) ensure that large-scale, customer-facing systems remain reliable, scalable, and efficient. In global tech and fintech companies, they split their time between building automation, monitoring production health, responding to incidents, and improving system resilience. Freshers in this role typically start with observability, scripting, and on-call shadowing before owning services.

Role and Technical Knowledge

1. 1

   What does an SRE do differently from a traditional DevOps engineer?

   Highlight that SREs apply software engineering to operations, focus on SLIs/SLOs, error budgets, and reducing toil through automation. Mention that DevOps is a broader culture while SRE is a specific implementation.

2. 2

   Explain SLI, SLO, and SLA with an example from a payments or banking service.

   Define SLI as a measured metric (e.g., request latency), SLO as the target (e.g., 99.9% of requests under 200ms), and SLA as the contract with consequences. Use a fintech example like UPI transaction success rate.

3. 3

   What is an error budget and how would you use it to decide when to stop feature releases?

   Explain that error budget is 1 minus SLO. If the budget is exhausted, freeze releases and focus on reliability. Show you understand the trade-off between innovation and stability.

4. 4

   How does DNS resolution work and what could go wrong in a microservices environment?

   Walk through recursive and iterative queries, caching, TTL. Mention issues like stale DNS caches, misconfigured records, or DNS as a single point of failure in service discovery.

Practical Scenarios and Troubleshooting

1. 5

   A production API is returning 500 errors for 10% of users. How do you troubleshoot?

   Start with dashboards and logs to identify the failing service, check recent deployments, correlate with metrics like CPU/memory, and use tracing to isolate the error. Mention communication with stakeholders and rollback if needed.

2. 6

   You need to reduce alert noise from a service that pages the on-call engineer every night. What steps do you take?

   Analyze alert history, identify non-actionable alerts, adjust thresholds, add suppression rules, and implement better health checks. Emphasize that alerts should be actionable and tied to SLOs.

3. 7

   How would you design a monitoring and alerting setup for a new microservice?

   Cover the four golden signals (latency, traffic, errors, saturation), use Prometheus for metrics, Grafana for dashboards, and set alerts on SLO breaches. Mention logging with ELK or similar and distributed tracing.

4. 8

   A deployment caused a memory leak in one pod. How do you detect and mitigate it?

   Detect via container memory metrics and OOM kills, use kubectl top or similar, then rollback the deployment. Mitigate by setting memory limits and requests, and add a postmortem action to improve testing.

Automation, Cloud, and Reliability Engineering

1. 9

   How would you automate the rollback of a failed deployment in a CI/CD pipeline?

   Describe using health checks and canary deployments, with automated rollback triggered by error rate or latency thresholds. Mention tools like Jenkins, Argo CD, or GitLab CI and keeping rollback idempotent.

2. 10

   What is infrastructure as code and why is it important for SRE?

   Explain that IaC treats infrastructure like software, enabling version control, repeatability, and peer review. Give examples like Terraform or CloudFormation and how it reduces configuration drift.

3. 11

   Explain how you would use Kubernetes liveness and readiness probes to improve reliability.

   Liveness probes restart unhealthy containers; readiness probes prevent traffic to pods not ready. Show you understand the difference and how misconfiguration can cause cascading failures.

4. 12

   How do you ensure high availability for a database in the cloud?

   Mention multi-AZ deployments, read replicas, automated failover, backups, and monitoring replication lag. Tie it to recovery time objective (RTO) and recovery point objective (RPO).

Behavioural and HR Questions

1. 13

   Tell me about a time you had to debug a problem under time pressure. How did you handle it?

   Use STAR method: describe the situation, your systematic approach, the tools you used, and the outcome. Emphasize calmness, communication, and learning from the incident.

2. 14

   How do you prioritize tasks when multiple production issues occur at once?

   Show you assess impact and urgency, communicate with stakeholders, and delegate if possible. Mention using severity levels and focusing on customer-facing issues first.

3. 15

   Why are you interested in a Site Reliability Engineer role at a global fintech company?

   Connect your interest in large-scale systems, automation, and financial technology. Mention the challenge of maintaining reliability in high-stakes environments and your desire to learn.

4. 16

   Describe a time you worked in a team to achieve a technical goal. What was your contribution?

   Highlight collaboration, clear communication, and your specific role. Show that you can work with developers, QA, and operations, and that you value shared ownership.