Free DVA-C02 flashcards

How do you fan out a copy of every event to several independent consumers, including SQS queues and an HTTP endpoint, on AWS?

Publish to an Amazon SNS topic and subscribe each consumer to it. SNS pushes a separate copy of every message to each subscriber, so subscribed SQS queues buffer events for their own pollers and an HTTP subscriber receives push delivery with retries. Each consumer then processes at its own pace.

A single shared Amazon SQS standard queue lets three consumers each receive every message published to it.

A standard SQS queue delivers each message to only one consumer, which then deletes it. Multiple pollers compete for messages rather than each getting a copy. To give every consumer every event you need SNS fan-out, where each subscriber receives its own copy.

Which Amazon Cognito component handles end-user sign-up, sign-in, and password reset without a custom user database?

An Amazon Cognito user pool is a fully managed identity directory that runs sign-up, sign-in, and password recovery flows. On successful authentication it issues JWT ID and access tokens. This removes the need to build and operate your own user store for credential management.

An Amazon Cognito identity pool provides hosted sign-up and sign-in screens and stores each user's profile and password.

An identity pool only exchanges an existing authenticated identity for temporary AWS credentials. It stores no user profiles or passwords and offers no sign-up directory. Managed sign-up, sign-in, and password storage come from a Cognito user pool instead.

Which AWS Lambda deployment package format supports a function whose unzipped code and dependencies reach roughly 900 MB?

A container image. Zip deployment packages, whether uploaded directly or pulled from Amazon S3, share a 250 MB unzipped limit across the function and its layers. A Lambda container image supports artifacts up to 10 GB, comfortably holding a 900 MB dependency set, and Lambda runs it directly from Amazon ECR as a single artifact.

Uploading a .zip directly through the Lambda console accepts artifacts of any unzipped size without extra steps.

A direct console .zip upload is capped at 50 MB zipped, and zip packages have a 250 MB unzipped limit shared by the function and layers. A 900 MB dependency set far exceeds this, so it cannot be deployed as a console zip upload and needs a container image instead.

To list every recent ERROR log event with its requestId, newest first, directly from a CloudWatch Logs log group, what should you use?

Run a CloudWatch Logs Insights query against the log group: it executes in place over the stored events. Filter on the parsed level field equal to ERROR, project the requestId with a fields clause, and sort by timestamp descending. This returns the exact failing events in time order without exporting data or building a pipeline.

A CloudWatch Logs metric filter on an ERROR pattern can return the requestId values of the failing requests.

A metric filter only emits a numeric count to a CloudWatch metric. It tells you how many errors occurred, not which requests failed, because it cannot return field values such as requestId. Use CloudWatch Logs Insights to retrieve and project individual field values.