3 AWS Lambda and Event-Driven Compute Free Online FlashCards

What does AWS Lambda provide?

AWS Lambda runs code in response to events without requiring you to manage the underlying servers.

What are the main parts of a Lambda function?

A Lambda function includes code, a runtime, a handler (entry point), and configuration.

Can Lambda execution-environment memory serve as durable storage?

Execution environments may be reused, but their memory and temporary files are not durable. Store persistent data in services such as Amazon S3 or DynamoDB.

What happens in a direct Lambda invocation?

With direct invocation, a service such as API Gateway, EventBridge, or S3 invokes the function.

How does a Lambda event source mapping work?

An event source mapping polls a queue or stream, such as Amazon SQS or DynamoDB Streams, then invokes the function with a batch of records.

Why should event processing be idempotent?

Idempotent processing ensures that reprocessing the same event does not create another unintended result, such as a duplicate charge or order.

What does a Lambda execution role control?

The execution role grants a function permission to access AWS resources. Apply least privilege by granting only the permissions needed for its task.

Where is permission for a service to directly invoke a function generally granted?

A direct invoker generally needs permission in the function’s resource-based policy. This is separate from the execution role’s resource-access permissions.

What factors guide the choice between Lambda and other compute services?

Choose compute based on workload duration, runtime and operating-system needs, control requirements, and traffic pattern; Lambda is not a general replacement for EC2 or containers.

How can Lambda aliases support safer deployments and rollbacks?

Publish an immutable version and point an alias, such as prod, to it. Moving the alias to another version supports deployment or rollback.

What does reserved concurrency do?

Reserved concurrency sets a function’s concurrency ceiling and reserves that capacity for it. The ceiling can protect other workloads but may cause throttling.

When is provisioned concurrency useful?

Provisioned concurrency prepares execution environments in advance to reduce initialization delay for latency-sensitive workloads; it adds charges.