Application Integration Flashcards

1
Q

What is Amazon SQS?

A

A fully managed message queuing service that enables you to decouple and scale microservices, distributed systems, and serverless applications.

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2
Q

What are the two types of SQS queues?

A

Standard Queues: Offer high throughput, best-effort ordering, and at-least-once delivery.

FIFO Queues: Strict message ordering and exactly-once processing.

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3
Q

What is the maximum message size for SQS?

A

256 KB (can be larger with SQS Extended Client)

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4
Q

What is a Dead Letter Queue (DLQ)?

A

An SQS queue that stores messages that failed to process after a number of attempts. Useful for debugging and troubleshooting.

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5
Q

What are message attributes in SQS?

A

Metadata that can be attached to SQS messages for filtering and routing.

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6
Q

Explain ‘at-least-once delivery’ in SQS.

A

SQS guarantees that messages will be delivered at least once, but duplicates are possible in rare cases.

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7
Q

What is the purpose of the ‘Delay Seconds’ attribute in SQS?

A

Allows you to delay the delivery of a message to a queue for a specified number of seconds.

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8
Q

How can you achieve ‘exactly-once delivery’ with SQS?

A

Use FIFO queues, which provide inherent message deduplication and ordering.

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9
Q

How can you scale SQS consumers?

A

By adding more consumers to poll the queue, SQS automatically handles the distribution of messages.

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10
Q

What are some ways to monitor SQS queues?

A

Use Amazon CloudWatch metrics (e.g., NumberOfMessagesSent, NumberOfMessagesReceived, ApproximateNumberOfMessagesVisible)

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11
Q

What is Amazon SNS?

A

A fully managed pub/sub messaging service that enables you to fan out messages to a large number of subscribers, including SQS queues, Lambda functions, and email addresses.

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12
Q

What are some benefits of using SNS?

A

High scalability

Message durability

Integration with various AWS services.

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13
Q

What types of endpoints can subscribe to an SNS topic?

A

SQS queues, Lambda functions, HTTP/S endpoints, email addresses, SMS numbers, mobile push notifications.

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14
Q

What is the purpose of message filtering in SNS?

A

Allows subscribers to receive only messages that match specific criteria defined in a filter policy.

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15
Q

How does SNS handle message delivery retries?

A

SNS retries failed deliveries to HTTP/S endpoints with exponential backoff.

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16
Q

What are the different message delivery protocols supported by SNS?

A

HTTP/S, email, SMS, SQS, Lambda, and mobile push notifications.

17
Q

What is the ‘fan-out’ pattern with SNS and SQS?

A

A design where one SNS topic sends the same message to multiple SQS queues for parallel processing.

18
Q

What is AWS Step Functions?

A

A serverless orchestration service that makes it easy to coordinate multiple AWS services into serverless workflows. Provides a visual console to build and manage workflows.

19
Q

What are some common use cases for Step Functions?

A

Microservice orchestration

Data processing pipelines

Machine learning workflows.

20
Q

What are the different types of states in Step Functions?

A

Task, Choice, Wait, Parallel, Map, Pass, Succeed, Fail.

21
Q

How can you handle errors in Step Functions workflows?

A

Use ‘Retry’ and ‘Catch’ fields within state definitions to handle specific error types and implement retry logic.

22
Q

What is the purpose of the ‘InputPath’ and ‘OutputPath’ fields in Step Functions state definitions?

A

Control which parts of the state input are passed to the task and which parts of the task output are passed to the next state.

23
Q

What is Amazon EventBridge?

A

A serverless event bus that makes it easy to connect applications with data from a variety of sources. Allows for real-time responses to events.

24
Q

What is the EventBridge Schema Registry?

A

Stores event schemas, allowing you to validate and govern the structure of events flowing through your event buses.

25
Q

What are the different ways to trigger an EventBridge rule?

A

Schedule (cron expressions), Event Pattern (matching events from AWS services or other sources).

26
Q

What are event buses in EventBridge?

A

Targets that receive events. You can have default event buses, custom event buses, and partner event buses.

27
Q

How can you archive and replay events in EventBridge?

A

Use the event archive feature to store events for a specified duration or indefinitely, and then replay them for auditing or debugging.

28
Q

What are some examples of events that can be sent to EventBridge?

A

S3 object created events, EC2 instance state changes, CloudWatch alarms, custom application events.

29
Q

What is the difference between SNS and EventBridge?

A

SNS is focused on pub/sub messaging, while EventBridge is a broader event bus that can route events between AWS services, SaaS apps, and your own applications.

30
Q

What is Amazon Managed Workflows for Apache Airflow (MWAA)?

A

A managed service that makes it easy to run Apache Airflow on AWS. Airflow is a platform for programmatically authoring, scheduling, and monitoring workflows.

31
Q

What is a DAG in Apache Airflow?

A

A Directed Acyclic Graph that represents a workflow, where nodes represent tasks and edges represent dependencies between tasks.

32
Q

How are workflows defined in Apache Airflow?

A

Using Python code to create Directed Acyclic Graphs (DAGs).

33
Q

What are some key features of MWAA?

A

Managed service - no need to install/maintain Airflow

Scalable

Integrates with many AWS services.

34
Q

How does MWAA handle scaling of Airflow workers?

A

MWAA automatically scales the number of worker containers based on the workload and configured limits.

35
Q

How can you access the Airflow web server in MWAA?

A

Through a private or public endpoint, managed by AWS IAM.

36
Q

What is the purpose of ‘Visibility Timeout’ in SQS?

A

Prevents other consumers from processing a message while it’s being handled by another consumer. The message is returned to the queue if not deleted within the timeout.