AWS Lambda
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What is AWS Lambda?
AWS Lambda is a serverless computing service that runs code in response to events and automatically manages the underlying infrastructure. It allows developers to focus on writing code without managing servers, scaling seamlessly as needed.
How does AWS Lambda pricing work?
AWS Lambda pricing is based on the number of requests and the compute time used. You get 1 million free requests and 400,000 GB-seconds of compute time monthly, and then pay per additional request and per GB-second beyond the free tier.
What languages does AWS Lambda support?
AWS Lambda natively supports several programming languages, including Node.js, Python, Ruby, Java, Go, .NET, and custom runtimes with the Runtime API.
Can AWS Lambda be used with AWS Step Functions?
Yes, AWS Lambda can be integrated with AWS Step Functions to build scalable, event-driven applications using state machines for orchestration, allowing complex workflows and services to be automated.
Is there a limit to AWS Lambda function execution time?
Yes, AWS Lambda functions have a maximum execution timeout of 15 minutes per invocation. This limit requires developers to optimize and design functions to complete within this time frame.
What are triggers in AWS Lambda?
Triggers are sources or events that invoke AWS Lambda functions. Common triggers include changes in S3 buckets, DynamoDB updates, API Gateway requests, and events from other AWS services that Lambda can respond to automatically.
How does AWS Lambda handle concurrency?
AWS Lambda manages concurrency by creating multiple instances of your function to handle simultaneous requests. The default concurrency limit can be adjusted, but AWS automatically scales up and down based on demand.
What is a Lambda layer?
A Lambda layer is an archive that contains additional code or data that a function requires. Layers enable sharing common dependencies, such as libraries and custom runtimes, across multiple Lambda functions.
Can AWS Lambda connect to a VPC?
Yes, AWS Lambda functions can be configured to access resources in a Virtual Private Cloud (VPC). This allows functions to interact with VPC-based databases and services when certain permissions and configurations are set.
How is security managed in AWS Lambda?
Security in AWS Lambda is managed via AWS Identity and Access Management (IAM), where roles and policies specify permissions for Lambda functions to access resources. Lambda functions also have environment variables and can use AWS Key Management Service (KMS) for encryption.
What is AWS Lambda@Edge?
AWS Lambda@Edge allows users to run Lambda functions at AWS CloudFront locations globally, making it possible to customize content delivery and perform serverless operations closer to the user's location, reducing latency.
How do you update a Lambda function?
A Lambda function can be updated by uploading a new deployment package or modifying code inline in the AWS Management Console, using the AWS CLI, or via AWS SDKs, which can automatically update or create function versions.
What is a deployment package in AWS Lambda?
A deployment package is a ZIP archive that contains Lambda function code and any dependencies required. The function executes based on the contents of this package when it is invoked.
How do events trigger AWS Lambda?
Events trigger AWS Lambda via integration with services like API Gateway, S3, DynamoDB, and others. When an event occurs, AWS Lambda executes the associated function, using the event data as input.
Can AWS Lambda be used with containers?
Yes, AWS Lambda supports deployment of functions using container images up to 10 GB in size. This allows the use of custom runtimes, dependencies, and application frameworks within Lambda's serverless environment.
What is an AWS Lambda function alias?
An alias in AWS Lambda is a pointer to a specific function version that remains unchanged when newer versions are deployed, providing a fixed, versioned endpoint for clients to use.
How does AWS Lambda ensure fault tolerance?
AWS Lambda automatically spreads functions across multiple Availability Zones, ensuring high availability and fault tolerance by replicating invocations and retries in case of failures.
What debugging options are available for AWS Lambda?
AWS Lambda supports debugging with AWS X-Ray for tracing requests and CloudWatch for logging. X-Ray helps visualize request flows, while CloudWatch logs can capture function execution and errors.
What is the maximum package size for AWS Lambda?
The maximum package size for an AWS Lambda function is 50 MB when uploading directly as a ZIP file and 10 GB when using a container image to deploy the function.
How do environment variables work in AWS Lambda?
Environment variables in AWS Lambda allow you to pass key-value pairs to your function. These can be used to configure functions dynamically without altering the code, and sensitive variables can be encrypted with AWS KMS.
Can AWS Lambda execute functions asynchronously?
Yes, AWS Lambda supports asynchronous execution, allowing functions to be triggered and processed without waiting for a response, suitable for tasks like logging, data processing, and operations that do not depend on immediate results.
What is included in an AWS Lambda execution environment?
The AWS Lambda execution environment contains a runtime for supported languages, storage for temporary data, integration with AWS services, and security configurations, running functions inside secure microVMs for isolation.
What are AWS Lambda cold starts?
A cold start in AWS Lambda occurs when a function is invoked without a warmed execution environment. This involves initializing a container, leading to increased latency for the initial function execution.
How is logging managed in AWS Lambda?
AWS Lambda automatically captures logs generated by the function and sends them to CloudWatch Logs, where developers can view and analyze logs for debugging and monitoring.
Can AWS Lambda functions have reserved concurrency?
Yes, reserved concurrency in AWS Lambda is a configuration that guarantees a set number of concurrent executions for a function without exceeding specified limits, providing predictable performance.
What purpose do AWS Lambda layers serve?
AWS Lambda layers enable code sharing across multiple Lambda functions, allowing developers to package libraries, custom runtimes, or other dependencies once and use them in multiple functions for consistency and efficiency.
How does AWS Lambda manage permissions?
AWS Lambda uses IAM roles and policies to manage permissions, ensuring only authorized functions can access necessary AWS services and resources under the principle of least privilege.
Can AWS Lambda communicate with external services?
Yes, AWS Lambda can communicate with external services via the internet if configured with appropriate network access or VPC configuration, enabling integration with APIs, third-party services, and more.
What is the role of API Gateway with AWS Lambda?
API Gateway serves as a front-door for AWS Lambda, providing RESTful endpoints for invoking Lambda functions, enabling HTTP-based interactions, and offering authentication, throttling, and monitoring capabilities.
Can AWS Lambda access RDS databases?
Yes, AWS Lambda can access RDS databases if configured within the same VPC and appropriate security group settings, enabling serverless applications to query databases directly.
How is versioning managed in AWS Lambda?
AWS Lambda versioning allows every update to a function to be snapshotted and accessed by a version number, ensuring access to stable code despite ongoing changes. Aliases help in managing different versions.
What is AWS Lambda provisioned concurrency?
Provisioned concurrency for AWS Lambda keeps function instances initialized and ready to respond quickly, minimizing cold start latency by maintaining pre-warmed instances to handle predictable, consistent workloads.
How can AWS Lambda be monitored?
AWS Lambda can be monitored using AWS CloudWatch for metrics (such as invocations, errors, and durations), AWS CloudTrail for logging API activity, and AWS X-Ray for tracing and performance analysis.
What does the 'Timeout' setting in AWS Lambda do?
The 'Timeout' setting in AWS Lambda specifies the maximum duration that a function can run before being automatically terminated. This can be set up to 15 minutes to prevent errant executions.
How does data retention work in AWS Lambda?
AWS Lambda stores function logs in CloudWatch Logs, with options to retain logs based on configured retention policies. Temporary storage up to 512 MB is available during execution in the function's sandbox.
How do you use AWS Lambda in a CI/CD pipeline?
AWS Lambda can be integrated into a CI/CD pipeline via AWS CodePipeline, CodeBuild, or third-party tools, enabling automated deployment and testing of Lambda functions as part of a continuous deployment process.
What are some common use cases for AWS Lambda?
Common use cases for AWS Lambda include running serverless backends, processing data streams, transforming data on the fly, image and video processing, real-time notifications, and running cron jobs without servers.
How do you deploy a Lambda function using the AWS CLI?
Deploying a Lambda function using the AWS CLI involves creating a function with the 'create-function' command, specifying the code package, runtime environment, handler, and necessary execution role.
What is the role of memory settings in AWS Lambda?
Memory settings in AWS Lambda determine the amount of memory allocated during function execution, influencing performance and cost. Increasing memory also increases CPU, impacting speed and cost efficiency.
Can AWS Lambda interact with AWS SNS?
Yes, AWS Lambda can interact with AWS SNS by subscribing to SNS topics. When messages are published to the topic, Lambda functions can be triggered to process the notifications.
How do scalability and performance work in AWS Lambda?
AWS Lambda automatically scales functions horizontally to handle the number of incoming requests, ensuring consistent performance without manual intervention, and applies optimizations like reserved concurrency and provisioned concurrency for predictable behavior.
How are timeouts configured for AWS Lambda?
Timeouts for AWS Lambda functions are configured per invocation to a maximum of 15 minutes, managing resource usage and ensuring long-running executions don't exceed planned execution limits, thus controlling costs and performance.
How is AWS Lambda integrated with event source mapping?
AWS Lambda's event source mapping allows functions to be automatically triggered by events from services like DynamoDB and Kinesis, polling for new records and sending them to Lambda for processing without manual triggering.
What is the maximum number of file descriptors available in AWS Lambda?
AWS Lambda offers up to 1,024 file descriptors per function execution, limiting the number of files or network connections a single invocation can manage concurrently.
How do reserved concurrency and unreserved concurrency differ in AWS Lambda?
Reserved concurrency allocates a specific number of concurrent executions to a function, ensuring availability, while unreserved concurrency refers to any potential spillover execution counted within the total account concurrency limit.
How does AWS Lambda work with S3 events?
AWS Lambda can be triggered by S3 events such as object creation, deletion, or updates. This allows automatic processing of data as it arrives, making it ideal for workflows involving data ingestion and processing.
What is the default memory allocation for AWS Lambda functions?
The default memory allocation for AWS Lambda functions is 128 MB, but it can be increased in 64 MB increments up to 10,240 MB, impacting function execution time and pricing.
Can AWS Lambda be scheduled to run automatically?
Yes, AWS Lambda can be scheduled using Amazon CloudWatch Events (now known as Amazon EventBridge), which allows functions to be triggered at specified intervals or cron-scheduled execution rules.
How do execution roles work in AWS Lambda?
Execution roles in AWS Lambda are IAM roles that grant the function permissions to execute and access necessary AWS resources, governed by specified policies, ensuring secure and controlled operation.