What is serverless in the context of AWS Lambda?

In the context of AWS Lambda, "serverless" refers to a cloud computing execution model where you don’t need to provision, scale, or maintain servers. AWS automatically handles all the infrastructure. You're charged only when your code is running (e.g., per request or per execution time), not for idle server time.

Difficulty: 5/10

Topics: auto-scaling, pay-per-use, cold start

Scenario Questions

0-2 years experience

1
How would you set up a simple Lambda function that processes S3 object‑created events and writes a log entry?
2
What happens if the Lambda execution exceeds the timeout you configured, and how does AWS handle it?
3
If you need to keep a small piece of state between invocations, what serverless‑compatible approach would you use?

2-5 years experience

1
Our API‑Gateway‑backed Lambda is seeing intermittent latency spikes. Walk me through how you’d debug the issue and which serverless characteristics might be responsible.
2
Explain the trade‑offs between using provisioned concurrency versus on‑demand for a Lambda that must meet a 100 ms SLA.
3
During a traffic burst the function is throttling. How would you adjust the architecture to handle the burst without over‑provisioning resources?

5-8 years experience

1
Design a serverless data pipeline that ingests clickstream events, transforms them, and loads them into Redshift. Discuss ordering, retries, and scaling considerations.
2
What security implications arise when a Lambda needs access to resources inside a VPC, and how would you mitigate the associated cold‑start penalty?
3
If you must guarantee exactly‑once processing across multiple Lambdas reading from the same SQS queue, what patterns would you employ and why?

8+ years experience

1
Your organization wants to migrate a legacy monolith to a serverless stack using Lambda, Step Functions, and EventBridge. Outline a high‑level migration strategy focusing on coupling, observability, and team ownership.
2
How would you evaluate the long‑term cost and operational impact of moving a high‑throughput, low‑latency service to Lambda versus keeping it on EC2/EKS?
3
When several teams share a common Lambda layer, what governance and versioning practices would you establish to avoid breaking changes?

Follow-up Questions

❓Can you describe a real incident where a cold start impacted user experience?
❓What CloudWatch metrics would you monitor to detect Lambda performance problems?
❓How would you decide between provisioned concurrency and on‑demand for a latency‑sensitive function?