Interview Questions and Answers on AWS Lambda

Summary

In this video, Rahul covers essential AWS Lambda concepts and answers common interview questions. He explains what AWS Lambda is, its serverless nature, and how it works without requiring server management. The video also highlights Lambda's supported programming languages, triggers, and how it interacts with AWS resources. Rahul discusses automation, event-based triggers, and how to manage input parameters dynamically. Additionally, he addresses how to log Lambda activity via CloudWatch. This video is an invaluable resource for those preparing for AWS Lambda-related interviews or looking to understand its core functionalities.

Takeaways

• 😀 AWS Lambda is a serverless computing service that allows you to deploy applications without managing servers.
• 😀 With AWS Lambda, you don't need to purchase EC2 instances or install web/application servers, as these are automatically managed by AWS.
• 😀 Serverless computing means the infrastructure is handled by the service provider, and users only pay for actual usage, not for idle servers.
• 😀 AWS Lambda works by uploading pre-written code, which it automatically deploys to a server or container without requiring additional configuration.
• 😀 Supported programming languages in AWS Lambda include Java, PowerShell, Node.js, Go, C#, Python, and Ruby.
• 😀 A trigger in AWS Lambda is an event or action that invokes the Lambda function, such as API Gateway, SES, or a third-party service.
• 😀 To access AWS resources from Lambda, ensure the Lambda function is launched with the correct VPC settings to enable resource access within the same network.
• 😀 You can automate dynamic parameters in AWS Lambda using EventBridge or SES to pass necessary values when triggering the function.
• 😀 EventBridge can be used to trigger AWS Lambda based on specific conditions, such as ensuring an EC2 instance has a required tag before running.
• 😀 AWS Lambda automatically writes logs to CloudWatch Logs, but you need to provide necessary permissions for Lambda to access and write logs.
• 😀 Custom logs can also be pushed to CloudWatch Logs from AWS Lambda using logger utilities, such as Python's logging module.

Q & A

What is AWS Lambda?

AWS Lambda is a serverless compute service that enables users to run code without provisioning or managing servers. The infrastructure is automatically handled by AWS.

What does 'serverless computing' mean in the context of AWS Lambda?

Serverless computing means that AWS Lambda takes care of all the server management. Users only need to upload their code, and AWS manages the necessary infrastructure. You only pay for what you use.

How does AWS Lambda work?

AWS Lambda works by allowing users to upload pre-written code. AWS automatically handles the creation of containers or servers, installs necessary runtimes, and runs the code on these managed servers.

Which programming languages are supported by AWS Lambda?

AWS Lambda supports several programming languages including Java, PowerShell, Node.js, Go, C#, Python, and Ruby. Users can upload code in these languages directly or as a ZIP file.

What is a trigger in AWS Lambda?

A trigger in AWS Lambda refers to the event or service that invokes a Lambda function. Common triggers include API Gateway, EventBridge, load balancers, or third-party tools.

How can you access AWS resources from an AWS Lambda function?

To access AWS resources from a Lambda function, you need to configure the Lambda function with the correct Virtual Private Cloud (VPC) settings. This ensures that Lambda can access the necessary resources within the specified VPC.

Why can't I list all AWS VPC components in my Lambda function?

If you're unable to list AWS VPC components like NIC cards, ensure that you select the correct VPC during the Lambda deployment process. This allows Lambda to access and list the VPC components.

How can you automate input parameters in AWS Lambda?

To automate input parameters, you can use EventBridge and SES to trigger Lambda. EventBridge allows you to pass dynamic event parameters (e.g., EC2 instance IDs) that Lambda can process.

How can you trigger AWS Lambda based on an event?

You can set up EventBridge rules to trigger Lambda based on specific events. For example, you can configure Lambda to check for a tag on an EC2 instance when it starts and take action (e.g., shut down the instance) based on the tag’s presence.

How are AWS Lambda logs stored?

By default, AWS Lambda writes logs to CloudWatch Logs. You need to provide the appropriate IAM role with permissions to allow Lambda to write to CloudWatch. Custom logs can also be sent to CloudWatch using logging utilities in your Lambda function.