21 AWS Step Functions Interview Questions and Answers

AWS Step Functions is a cloud service that helps you coordinate multiple AWS services into serverless workflows. This can make it easier to build and update apps that use a variety of AWS services. If you’re interviewing for a position that involves AWS Step Functions, you’ll want to be prepared to answer questions about the service. In this article, we’ll review some of the most common AWS Step Functions interview questions.

AWS Step Functions Interview Questions and Answers

Here are 21 commonly asked AWS Step Functions interview questions and answers to prepare you for your interview:

1. What are AWS Step Functions?

AWS Step Functions is a cloud service that helps you coordinate multiple AWS services into serverless workflows so you can build and update apps quickly and easily. With Step Functions, you can design and run workflows that stitch together services such as AWS Lambda and Amazon ECS into feature-rich applications.

2. What is the usage of AWS Step Functions?

AWS Step Functions is a cloud service that helps you coordinate multiple AWS services into serverless workflows so you can build and update apps quickly and easily. Using Step Functions, you can design and run workflows that stitch together services such as AWS Lambda and Amazon ECS into feature-rich applications.

3. Can you explain what a state machine is in the context of AWS Step Functions?

A state machine is a set of defined states that an entity can be in, and the transitions between those states. In AWS Step Functions, a state machine defines the states and transitions of a workflow.

4. Can you give me an example of a simple, real-world application that would use AWS Step Functions?

A simple, real-world application that would use AWS Step Functions would be a process that needs to run a series of tasks in a specific order, and then take an action based on the results of those tasks. For example, you could use Step Functions to process a series of images and then, based on the results of the image processing, either send an email notification or trigger a Lambda function to perform additional processing.

5. How can I create and manage a state machine using AWS Step Functions?

You can create a state machine using AWS Step Functions by creating a JSON file that defines the states and transitions of your state machine. You can then use the AWS Step Functions console or the AWS Command Line Interface (CLI) to create and manage your state machine.

6. How do I name my state machines and states when using AWS Step Functions?

You can name your state machines and states when using AWS Step Functions by using the Name property when creating your state machine or state.

7. How do I get started with AWS Step Functions?

You can get started with AWS Step Functions by creating a state machine using the AWS Management Console, AWS Command Line Interface, or AWS SDK.

8. Is it possible to invoke a step function from another step function? If yes, then how?

Yes, it is possible to invoke a step function from another step function. You can do this by using the AWS SDK to call the InvokeStepFunction API action.

9. Do you know any other ways to execute a step function besides using API calls or CLI commands?

Yes, there are other ways to execute a step function besides using API calls or CLI commands. For example, you can use the AWS Management Console or the AWS SDKs.

10. How does the execution timeout work for AWS Step Functions?

The execution timeout for AWS Step Functions is the amount of time that the service has to complete a task before it is considered timed out. This timeout can be set by the user and is measured in seconds. If a task does not complete within the specified timeout, then the Step Function will move on to the next task.

11. How much does it cost to run a step function?

The cost of running a step function depends on the number of state transitions that are executed. Each state transition costs $0.025 per 100,000 executions.

12. How long will the results of a step function be available for access by clients?

The results of a step function will be available for access by clients for as long as the step function is running. If the step function is terminated, then the results will no longer be available.

13. How do AWS Step Functions handle errors during execution?

AWS Step Functions will automatically retry an activity that fails due to an error, up to a maximum number of times that you specify. If the activity still fails after all retries are attempted, then AWS Step Functions will move the activity to a terminal state.

14. Can you explain the difference between Activity Timeouts and Heartbeats?

Activity timeouts are used to set a limit on how long an activity can run before it times out. This is useful for ensuring that activities do not run for too long and end up costing more money than necessary. Heartbeats, on the other hand, are used to check on the status of an activity and make sure that it is still running. If an activity does not respond to a heartbeat, then it is assumed to have timed out and will be terminated.

15. How can you avoid repetition when developing complex applications involving several step functions?

One way to avoid repetition when developing complex applications involving several step functions is to use AWS Lambda functions. Lambda functions can be used to encapsulate code that needs to be executed in multiple step functions. This allows you to avoid having to duplicate code across multiple step functions.

16. How do you monitor your step functions once deployed?

You can monitor your step functions using Amazon CloudWatch. You can create alarms to trigger when certain events occur, and you can also view logs to see what is happening inside your step function at any given time.

17. How should you design your app’s architecture if you have multiple steps that need to synchronize their responses before proceeding further?

In this case, you would want to use AWS Step Functions to coordinate the different steps. This would allow you to design your app so that each step can proceed independently, but still coordinate their responses as needed.

18. Which of the following services work best with AWS Step Functions:

AWS Lambda, Amazon S3, Amazon DynamoDB, Amazon Kinesis, and Amazon Simple Notification Service (SNS) all work well with AWS Step Functions.

19. What’s the maximum size allowed for an input in AWS Step Functions?

The maximum size allowed for an input in AWS Step Functions is 1 MB.

20. What is the main difference between task success and task failure in AWS Step Functions?

The main difference between task success and task failure in AWS Step Functions is that task success results in the execution of the next task in the state machine, while task failure causes the state machine to move to the fail state.

21. What happens if some tasks fail while running on parallel mode within a step function?

If some tasks fail while running on parallel mode within a step function, then the entire step function will fail. This is because the step function is designed to run all tasks in parallel, and if even one task fails, it means that the entire function has failed.