What is AWS Lambda?
AWS Lambda is a serverless computing service provided by Amazon Web Services (AWS). It allows you to run code in response to events and automatically manages the underlying compute resources.
What is Auto Scaling in Lambda?
AWS Auto Scaling is a feature that allows automatic configuration and scaling of instances in AWS Lambda. It doesn't require manual intervention and can be based on predefined metrics and thresholds. When a threshold is crossed, it can horizontally scale the instances.
What are the languages supported by AWS Lambda?
AWS Lambda supports several programming languages, including Java, Python, JavaScript (Node.js), C#, Ruby, Go, and PowerShell.
What is the execution time limit for DDOS in Lambda?
The execution time limit for a Lambda function during a DDOS (Distributed Denial of Service) attack is five minutes.
What makes Lambda a time-saving approach?
Lambda offers several features that contribute to its time-saving capabilities. It stores data in local server memory, allows direct database interaction without impacting performance, and provides simple testing techniques, such as integration testing with multiple vendors.
What are the best practices for security in Lambda?
Best practices for security in Lambda include using AWS IAM (Identity Access and Management) to control access, granting specific user access to specific roles, restricting access to untrusted hosts, and regularly updating security protocols.
What are the limitations of AWS Lambda?
Some limitations of AWS Lambda include a default deployment package size of 50 MB, limited ephemeral disk space (512 MB), longer execution time for functions with lower memory allocation, a memory range of 128 MB to 10,240 MB, and a maximum execution timeout of 15 minutes.
What is elastic block storage in Lambda?
Elastic Block Storage (EBS) is Amazon's virtual storage network that can be used with Lambda. It can tolerate faults, ensuring data integrity, and can be provisioned and allocated. EBS can also be connected to an API.
How does Lambda handle failure during event processing?
Lambda functions can run in synchronous or asynchronous mode. In synchronous mode, a function returns an exception to the calling application when it fails. In asynchronous mode, a failed function is retried at least three times.
Is vertical scaling possible in Lambda?
Yes, vertical scaling is possible in Lambda. It involves switching to a larger instance, pausing and detaching the existing instance, and noting the ID of the new device to continue the process.
How is a Lambda function executed?
Lambda functions can be executed through various methods, including the Lambda console, Lambda API, AWS SDK, AWS CLI, and AWS toolkits.
Name a simple method to improve performance in AWS Lambda.
Improving performance in AWS Lambda can be achieved by using RAID (Redundant Array of Independent Disks), a Linux software that can also enhance security.
In how many ways can AWS Lambda be used?
AWS Lambda can be used in multiple ways, such as event-driven computing (triggered by events like changes in an Amazon S3 bucket or AWS DynamoDB), running code in response to HTTP requests through Amazon API Gateway, and handling API calls made using AWS SDKs.
How does AWS Lambda secure my code?
AWS Lambda secures code by encrypting it and storing it in Amazon S3 buckets. It performs integrity checks on the code while it is running.
Advanced AWS Lambda Interview Questions
What are the restrictions applied to the AWS Lambda function code?
While AWS Lambda has few restrictions on operating system activities and standard programming languages, it does impose limitations on activities such as disabling instances and trace calls, inbound network connections, debugging systems, and TCP ports. It also enforces restrictions on outbound data connections.
How to get started with a serverless application?
To start with a serverless application, one should use the AWS Lambda console, download a blueprint, and work with AWS SAM (Serverless Application Model) files and ZIP files. AWS CloudFormation commands can be used for packaging and deploying the application code.
What are the disadvantages of using the serverless approach?
The serverless approach in AWS Lambda has its limitations, including less control over vendor operations, potential downtime, system functionality loss, and a lack of dedicated hardware. Customer errors can also lead to problems.
What is the difference between an anonymous class and the Lambda function?
The key difference between an anonymous class and a Lambda function is the use of keywords. Lambda functions are used to resolve functional classes, while anonymous classes resolve anonymous functional classes.
Is Lambda Expression a nameless suspension of code?
Yes, a Lambda Expression is a nameless suspension of code.
What kind of code can run on AWS Lambda?
AWS Lambda can run various types of code, including real-time file processing, data sorting and validation, filtering, third-party API requests, and more.
What are final variables and effectively final variables in Lambda?
Final variables cannot be modified once assigned, while effectively final variables can change in their initial stages before being assigned a value. Effectively final variables are useful in testing and can be equipped with additional features.
How does AWS Lambda work?
AWS Lambda operates in a straightforward four-step process: uploading code, setting up code triggers from various sources, running code when triggered, and dynamically allocating computing resources based on the workload.
What can one build with AWS Lambda?
AWS Lambda can be used to build a wide range of applications, including real-time file processing, data transformation, data processing, data validation, filtering, and handling API calls.
Do Lambda-based functions stay available after code or configuration changes?
Yes, Lambda-based functions remain available even after code or configuration changes. During an update, there is a brief period, typically less than a minute, during which requests can be served by either the old or new version of the function.
What is the difference between AWS Lambda and Amazon EC2?
AWS Lambda and Amazon EC2 are different compute services. AWS Lambda is a serverless compute service that runs code in response to events and automatically manages the underlying infrastructure. Amazon EC2 provides virtual machines (EC2 instances) where you have full control over the operating system and can run various applications.
What are Lambda layers, and how are they used?
Lambda layers are a distribution mechanism for libraries, custom runtimes, and other function dependencies in AWS Lambda. You can use layers to manage common code and resources across multiple Lambda functions, reducing duplication and making it easier to update shared dependencies.
How does AWS Lambda pricing work?
AWS Lambda pricing is based on the number of requests and the execution duration of your functions. You are charged for the total number of requests and the compute time in milliseconds. You can choose the amount of memory allocated to your function, affecting the cost and execution time.
What is the significance of the VPC (Virtual Private Cloud) in AWS Lambda?
A Lambda function can be configured to run within a VPC, allowing it to access resources in that VPC. This is particularly useful when your Lambda function needs to interact with resources like RDS databases or private subnets. It provides network isolation and security for your functions.
Explain the difference between synchronous and asynchronous invocation in Lambda.
In synchronous invocation, a Lambda function is triggered and runs immediately in response to an event, and the calling application waits for a response. In asynchronous invocation, the function is triggered, but the calling application does not wait for the function to complete. Asynchronous invocations are typically used for background tasks or event-driven processing.
How can you monitor the performance and execution of AWS Lambda functions?
AWS CloudWatch is commonly used for monitoring Lambda functions. You can create custom CloudWatch metrics, set up alarms, and access logs for detailed information on function performance. AWS also provides a service called AWS X-Ray for tracing and analyzing the execution of serverless applications.
What is the difference between AWS Lambda and AWS Fargate?
AWS Lambda is a serverless compute service for running code in response to events, while AWS Fargate is a compute engine for running containers. Lambda is designed for event-driven, short-duration functions, whereas Fargate is suitable for running longer-lasting containerized applications.
What are the main components of an AWS Lambda function?
An AWS Lambda function consists of the function code, runtime, handler, and optional configuration settings. The function code is the code you want to execute, the runtime is the environment in which the code runs, and the handler is the entry point for the execution.
What is the AWS Lambda Execution Environment?
The AWS Lambda Execution Environment is the runtime environment in which your function code executes. It includes the operating system, runtime libraries, and other dependencies necessary for running your function. AWS manages this environment for you.
What is the purpose of the AWS Serverless Application Model (AWS SAM)?
AWS SAM is an open-source framework for building serverless applications. It simplifies the deployment and management of serverless applications by providing a template language for defining resources, functions, and event sources. It's often used in conjunction with AWS CloudFormation for infrastructure as code.
What is the difference between AWS Lambda and Amazon ECS (Elastic Container Service)?
AWS Lambda is a serverless compute service that runs individual functions in response to events. Amazon ECS is a container orchestration service that manages Docker containers running in clusters. Lambda is typically used for event-driven, short-duration tasks, while ECS is used for long-running containerized applications.
These questions and answers cover various aspects of AWS Lambda, from basic concepts to more advanced topics. They can be valuable for preparing for interviews related to AWS Lambda and serverless computing.