AWS Lambda -Interview questions and answers.

Basics and Fundamentals:

1. What is AWS Lambda?

   • AWS Lambda is a serverless compute service that allows you to run code without provisioning or managing servers.

2. What programming languages are supported by AWS Lambda?

   • AWS Lambda supports multiple programming languages, including Node.js, Python, Java, C#, and Go.

3. Explain the concept of serverless computing.

   • Serverless computing abstracts server management, allowing developers to focus solely on writing and deploying code, paying only for the actual compute time used.

Lambda Functions and Triggers:

1. How do you create a Lambda function?

   • Lambda functions can be created using the AWS Management Console, CLI, or SDKs by specifying the runtime, code, and configurations.

2. What are event sources or triggers in Lambda?

   • Event sources or triggers are services that invoke Lambda functions. Examples include S3, API Gateway, DynamoDB, SNS, and CloudWatch Events.

3. Explain the relationship between API Gateway and AWS Lambda.

   • API Gateway acts as a trigger for Lambda functions, allowing you to create and expose RESTful APIs that execute Lambda functions in response to HTTP requests.

Execution Environment and Scaling:

1. How does AWS Lambda manage the execution environment?

   • Lambda manages the execution environment, automatically scaling resources and handling infrastructure provisioning based on incoming requests.

2. What is a cold start in AWS Lambda? How can it be mitigated?

   • Cold start refers to the initial latency when a Lambda function is invoked for the first time. It can be mitigated by implementing strategies like warming up functions or using provisioned concurrency.

3. How does AWS Lambda handle scalability and concurrency?

   • Lambda scales automatically by provisioning new containers to handle increased concurrency, ensuring functions are executed in parallel.

Integration and Deployment:

1. Explain the deployment process for Lambda functions.

   • Lambda functions can be deployed manually through the AWS Management Console or using automation tools like AWS SAM (Serverless Application Model) or CloudFormation.

2. How do you integrate Lambda functions with other AWS services?

   • Lambda integrates with various AWS services either as event sources or by utilizing AWS SDKs to interact with services like S3, DynamoDB, SQS, etc.

3. Can you update the code of a deployed Lambda function?

   • Yes, Lambda functions can be updated by uploading a new version of the code or by using continuous deployment tools integrated with Lambda.

Security and Permissions:

1. How is security managed in AWS Lambda?

   • Security in Lambda is managed through IAM roles and policies, allowing fine-grained control over function permissions and access to AWS resources.

2. Can Lambda function access resources within a VPC (Virtual Private Cloud)?

   • Yes, Lambda functions can be configured to access resources within a VPC using VPC configurations and security groups.

Error Handling and Monitoring:

1. How does AWS Lambda handle errors and retries?

   • Lambda provides options to handle errors by configuring dead-letter queues (DLQs) for asynchronous invocations or implementing custom error handling within the function.

2. What monitoring tools are available for AWS Lambda?

   • AWS CloudWatch is the primary monitoring tool for Lambda, providing metrics, logs, and alarms for function invocations, errors, and performance.

Performance Optimization and Best Practices:

1. What are some best practices for optimizing Lambda functions?

   • Best practices include minimizing package size, using provisioned concurrency, optimizing function duration, and leveraging caching.

2. How can you reduce the cost associated with AWS Lambda?

   • Cost reduction strategies include optimizing function execution time, leveraging provisioned concurrency, and controlling function memory allocation.

Scenario-based Questions:

1. Scenario: You have a Lambda function that is timing out frequently. How would you troubleshoot and resolve this issue?

   • (Potential answer: Check the function's code for inefficiencies, optimize long-running operations, increase the allocated memory, and monitor execution time for improvements.)

2. Scenario: A Lambda function is throwing errors due to permissions issues when accessing an S3 bucket. How do you diagnose and fix this problem?

   • (Potential answer: Review the function's IAM role permissions and ensure it has the necessary permissions to access the S3 bucket. Adjust IAM policies accordingly.)

These questions cover a wide range of topics related to AWS Lambda, offering insights into various aspects of its functionality, integration, performance optimization, and troubleshootinI hope this helps, you!!

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