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

What the job involves

Site Reliability Engineers (SREs) at global tech companies ensure that large-scale, distributed systems are reliable, scalable, and efficient. Day to day, they blend software engineering with systems engineering to build automation, monitor services, respond to incidents, and improve system resilience. They work closely with development and operations teams to maintain service level objectives (SLOs) and drive continuous improvement.

Role and Technical Knowledge

1. 1

   What is the difference between a Site Reliability Engineer and a DevOps Engineer?

   Highlight that SRE focuses on reliability, SLOs, and error budgets, while DevOps emphasizes collaboration and automation across the lifecycle. Mention that SRE is a specific implementation of DevOps principles.

2. 2

   Explain the concept of an error budget and how it influences decision-making.

   Define error budget as the acceptable amount of downtime derived from SLOs. Explain how it balances innovation and reliability, and how it guides release decisions.

3. 3

   What are SLIs, SLOs, and SLAs? Provide examples.

   SLI is a metric (e.g., latency), SLO is a target for that metric (e.g., 99.9% availability), and SLA is a contract with consequences. Give concrete examples relevant to a service.

4. 4

   How would you monitor a microservices-based application?

   Discuss metrics, logs, and traces; mention tools like Prometheus, Grafana, ELK, and Jaeger. Emphasize the need for distributed tracing and alerting on SLOs.

Practical Scenarios

1. 5

   A service is experiencing high latency. How would you troubleshoot it?

   Outline a systematic approach: check metrics (CPU, memory, network), logs, and traces; identify bottlenecks; and consider recent changes. Mention using tools like top, netstat, and APM solutions.

2. 6

   Describe how you would automate the deployment of a web application.

   Cover CI/CD pipeline steps, infrastructure as code (e.g., Terraform), configuration management (e.g., Ansible), and container orchestration (e.g., Kubernetes). Highlight rollback strategies.

3. 7

   You need to reduce cloud costs without impacting reliability. What steps would you take?

   Suggest rightsizing instances, using spot instances, auto-scaling, and storage lifecycle policies. Emphasize monitoring and analysis of usage patterns.

4. 8

   How would you handle a sudden spike in traffic to your service?

   Discuss auto-scaling, load balancing, caching, and rate limiting. Mention the importance of capacity planning and load testing.

Behavioral and HR

1. 9

   Tell me about a time you worked in a team to solve a technical problem.

   Use the STAR method to describe the situation, your role, actions taken, and the outcome. Highlight collaboration and communication.

2. 10

   Why do you want to work as a Site Reliability Engineer?

   Express interest in combining software engineering with systems operations, and a passion for building reliable systems. Relate to personal projects or coursework.

3. 11

   How do you handle pressure during critical incidents?

   Emphasize staying calm, following incident response procedures, communicating clearly, and learning from post-mortems. Give an example if possible.

4. 12

   Where do you see yourself in five years?

   Show a desire to grow technically, perhaps into a senior SRE or architect role, and to contribute to the company's reliability goals.

Problem Solving and Coding

1. 13

   Write a Python script to parse a log file and count the number of errors.

   Demonstrate file I/O, string manipulation, and use of regular expressions. Discuss efficiency and error handling.

2. 14

   How would you design a system to monitor the health of thousands of servers?

   Outline a scalable architecture using agents, a message queue, and a time-series database. Mention alerting and visualization components.

3. 15

   Given a scenario where a service is down, how would you debug it using Linux commands?

   Mention checking processes (ps, top), logs (tail, journalctl), network (netstat, ss), and disk usage (df, du). Explain how to isolate the issue.

4. 16

   Implement a function to check if a string is a palindrome, considering only alphanumeric characters.

   Show clean code with two pointers or filtering. Discuss time and space complexity.