AWS Lambda Interview Questions and Answers

Top AWS Lambda Interview Questions and Answers

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AWS Lambda is a widely-used service provided by Amazon, that enables users to execute code without the requirement of using specific programming languages. 

Acquiring proficiency in AWS Lambda can significantly enhance your performance in AWS Cloud Practitioner interviews at leading tech companies, irrespective of your experience level. 

 This blog post includes AWS Lambda interview questions and answers and aims to enhance your familiarity with the criteria established by AWS tools, elevating your prospects for success in upcoming data engineering interviews.

Let’s dive in!

Top 25 AWS Lambda Interview Questions and Answers

Here are the 25 AWS Lambda interview questions designed to support your pursuit of a successful career as a data engineer.

1. Define AWS Lambda.

AWS Lambda represents a serverless computing technology within Amazon Web Services (AWS), characterized by its event-driven architecture. 

With Amazon Lambda, AWS takes charge of all infrastructure aspects, from selecting the appropriate AWS services to deployment and maintenance.

Rather than dealing with infrastructure management intricacies, developers can write programs in various programming languages and runtimes, submitting them to AWS Lambda for swift and flexible execution.

In AWS Lambda, code responds to events triggered by AWS services, such as file additions/deletions in an S3 bucket or making HTTP calls to the Amazon API Gateway. It is important to note that Amazon Lambda is best suited for executing background tasks.

The key advantage lies in allowing developers to focus on core product development and business functionalities, eliminating the need to handle tasks like operating system access management, updates, right-sizing, provisioning, and scalability. 

An illustrative example of AWS Lambda’s capabilities is the ability to derive multiple data outputs from a single source, showcasing its versatility in handling complex tasks seamlessly.

2. List out the features of AWS Lambda.

AWS Lambda assists in the creation of scalable, secure, and extendable Lambda applications. The following are some of the features of AWS Lambda:

  • It furnishes features such as concurrency limits to achieve full control over the production applications to achieve scalability.
  • It has the features such as image tooling to create, test, and deploy the lambda functions
  • It has a code-signing feature to allow the non-modified code from authorized developers to add the right security and trust restrictions
  • It uses an extension tool such as Lambda extension to connect with the respective tools easily.
  • It also has a feature that furnishes sample codes to assist the users in integrating AWS lambda without others’ help.
  • Database Proxy is a unique tool that helps in controlling database pool connections and redirects the requests from one function to another.
  • Amazon Elastic File System can be employed to read, write, and manage massive data of any size.

3. Enumerate the languages supported by AWS Lambda.

AWS Lambda supports the following languages:

  • Java
  • Python
  • js
  • C#
  • Ruby
  • Go
  • PowerShell

4. Explain the concept of automated deployment.

The automated deployment is similar to the programming in other languages and it cuts down many issues associated with the deployment. It also cuts down the interferences made by humans and this helps the organization ensure quality-based outcomes. 

Employing AWS Lambda can help automate repetitive tasks by triggering them with events or by running them at a fixed time. 

5. Describe auto-scaling within the context of Lambda.

It is one of the major features of AWS and it helps to automate the configuration and spinning up new instances. The AWS auto-scaling does not need any interference at any point in time. However, users can control everything via metrics and thresholds. To enable this feature, you need to cross the threshold without any interference and it results in the scaling of instances horizontally. 

6. Identify the types of storage services offered by Amazon.

Amazon offers varied effective storage opinions in terms of performance and durability. Here are some of them:

7. What execution limit does Lambda have during a DDOS scenario?

While performing the DDOS, AWS lambda takes an execution time of about five minutes. 

8. Elaborate on your comprehension of AMI.

An Amazon Machine Image (AMI) is a unique form of virtual appliance employed to create a virtual machine within EC2, acting as the fundamental building block for deploying services via EC2. When initiating an instance, specifying the AMI is essential.

Additionally, the option to use different AMIs is available when launching instances. If the objective is to initiate several instances with identical configurations, it necessitates multiple instances derived from the same AMI.

9. Is there a correlation between Instances and AMI?

An Amazon Machine Image (AMI) is a repository containing the information required for you to launch a virtual machine on AWS including the operating system, OS instantiation instructions, etc. An instance is a running instance of a virtual machine, that is created from the AMI.

 10. What are the best practices of AWS Lambda Function?

Here are the recommended AWS Lambda function practices:

  • Optimize your deployment bundle by minimizing its size, reducing the download and unpack time before invocation.
  • Avoid implementing recursive code in your Lambda function, preventing self-invocation until a specific condition is met.
  • Conduct load tests on your Lambda function to determine the optimal timeout value for enhanced performance.
  • Regularly review and eliminate unused AWS Lambda functions to avoid unnecessary impacts on deployment package size limits.
  • Utilize AWS Lambda function metrics and CloudWatch Alarms instead of modifying metrics within your Lambda function code.
  • Experiment with different batch and record sizes to fine-tune event source polling frequencies, ensuring optimal responsiveness for your function’s tasks.

11. What are the AWS lambda use cases?

AWS Lambda is a versatile tool, and it can be used in multiple use cases and situations, such as:

  • The AWS Lambda can be used to log events in a cloud watch to transfer the logs to tools such as Kibana and Elasticsearch
  • The websites can invoke the AWS Lambda over the HTTP using the Amazon API Gateway via HTTP endpoint
  • In mobile applications, you can create lambda functions to process the events the customized application.

12. What are the components of AWS Lambda?

AWS lambda has three major components such as:

  • A function: This is the actual code that is used to perform the live task 
  • A configuration: It mentions how your function can be executed.
  • An event source (optional): The event serves as the trigger for the function and can be activated by various AWS services or a third-party service. 

 13. What are the advantages of AWS Lambda?

The key benefits of AWS Lambda such as:

  • It executes the code without the need to supply or manage the infrastructure
  • It grows the application automatically by the code execution directly to the event
  • You need to pay for every millisecond of running the code as well as the times it is triggered with the AWS Lambda
  • You can also speed up the execution of your code with AWS Lambda by selecting the apt memory size of the function.
  • It effectively interacts with the AWS services including DynamoDB, S3, and API Gateway, which allows you to create the functional applications using the AWS Lambda functions.

14. What are the factors that influence AWS Lambda Pricing?

Here’s a breakdown of the key factors influencing AWS Lambda pricing:

Feature Description
Request charges $0.20 per million requests. The initial 1 million requests per month incur no charges.
Compute charges $0.00001667 per GB-second. The first 400,000 GB seconds each month are covered in the free tier.
Data Transfer No charges for data transfer in or out of Lambda.
Ephemeral storage $0.0000000309 per GB-second. The first 512 MB of storage is included in the free tier.
Logs $0.053 per GB stored. The first 5 GB of storage monthly is free.

15. Why AWS Lambda is significant for Serverless Architecture?

AWS Lambda Architecture stands out as a significant choice for executing application code in the development of Serverless applications due to its support for a wide array of common languages and runtimes. 

Employing AWS Lambda layers as the central logic for a serverless application in a traditional, server-based context can enhance development speed, foster greater experimentation, and spur creativity. 

Building a Serverless stack in AWS becomes effortless by incorporating Lambda services for computing, a database management system, and an HTTP gateway service. Amazon Lambda seamlessly integrates with various other AWS services, including API Gateway, DynamoDB, and RDS.

16. What are the limitations of AWS Lambda?

The key limitations of AWS Lambda such as:

  1. The AWS Lambda service is not suitable for small projects.
  2. The maximum size of an event request is found to be 128 KB.
  3. The memory capacity of AWS Lambda deviates from 128 to 1536 MB
  4. AWS Lambda restricts the code execution timeout to about 5 minutes.
  5. The number of concurrent executions is found to be 100.
  6. Lambda functions permit you to write the logs to CloudWatch to keep track of or debug the functions.
  7. AWS Lambda is completely dependent on AWS for infrastructure and thus you cannot be able to install any extra software if the code needs it.
  8. AWS Lambda is reliable on AWS for infrastructure and if your code needs it, you need not be able to install any others.

17. How to share large files between lambda functions?

To share the files between the different lambda functions, we can use Elastic File System (EFS).

Establish an access point in your created Amazon Elastic File System (EFS) with the necessary permissions, and incorporate this access point into your Lambda function’s mount path. Any files written to this mount path will be available to other Lambda functions, granted they possess the necessary permissions for that specific mount path.

18. What are the disadvantages of using the serverless approach?

While AWS Lambda provides advantages and drawbacks depending on the task, the serverless approach has its downsides. Strict vendor control imposes an upper limit, potentially leading to increased downtime.

There is a risk of losing system functionality and encountering system limits without dedicated hardware in the AWS serverless approach. Additionally, problems can arise from customer errors in most cases.

19. Difference Between Anonymous Class and Lambda Function.

An important distinction between an anonymous class and a Lambda function lies in the use of keywords. In Lambda functions, keywords are employed to resolve functional classes, whereas in anonymous classes, they are used to resolve anonymous functional classes.

20. How does Code Execution take place on AWS Lambda?

AWS Lambda supports various activities. It can be utilized for building mobile backends from Amazon DynamoDB for data retrieval and transformation. Handlers play a role in transforming and compressing objects during their upload to Amazon S3.

AWS Lambda enables serverless processing of streaming data through Amazon Kinesis. Additionally, it facilitates the reporting and auditing of API calls to any Amazon web service, among various other functionalities.

21. What happens to the lambda functions if a lambda layer is removed?

If a lambda layer is deleted, the lambda functions already utilizing that layer will continue to operate. Lambda layers and functions are integrated during deployment, so the existing functions remain unaffected. However, it’s important to note that the deleted lambda layer cannot be employed for creating new lambda functions.

22. What is Elastic Block Storage in Lambda:

Amazon’s Elastic Block Storage (EBS) can be described as a virtual storage area network suitable for launching tasks. It boasts fault tolerance, ensuring data loss prevention even if the disk is damaged within the RAID. EBS allows provisioning and allocation of storage, and it can also be connected to an API if needed.

23. How to handle failure during Event Processing in Lambda?

Lambda operates functions in either synchronous or asynchronous modes. In synchronous mode, if a function fails, it raises an exception to the calling application. In asynchronous mode, a failed function is retried at least three times.

24. Does AWS Lambda supports Vertical Scaling?

Yes, Lambda supports vertical scaling, a highly sought-after feature. This capability is particularly useful when there is a need to spin a larger instance. If an instance is already in use, it can be paused and detached from the server, with the importance of noting the ID of the new device for continuity in the process.

25. What is SQS?

SQS, or Simple Queue Service, serves as a means of facilitating communication and information exchange between diverse hosts and connectors within Lambda. It enables seamless connectivity among Lambda’s various functional components, allowing disparate elements to interact and share data. This approach not only fosters efficient communication but also helps in minimizing failures, as it ensures effective understanding and connection between different components.

Conclusion

Hope this blog offers important AWS Lambda Interview Questions and Answers to ace your interviews easily and helps to elevate your career to new heights in the cloud industry.

In addition to reviewing these interview questions, it’s essential to delve into real-world AWS Lambda projects. This exploration will provide a comprehensive understanding of how Lambda integrates into the broader AWS Ecosystem. Demonstrating practical knowledge and expertise in these projects during the interview can greatly benefit your candidacy. 

If you aspire to become an AWS Certified Cloud Practitioner, it is recommended to invest your time in practical settings such as AWS hands-on labs and sandboxes to enhance your skill set.

About Karthikeyani Velusamy

Karthikeyani is an accomplished Technical Content Writer with 3 years of experience in the field where she holds Bachelor's degree in Electronics and Communication Engineering. She is well-versed in core skills such as creative writing, web publications, portfolio creation for articles. Committed to delivering quality work that meets deadlines, she is dedicated to achieving exemplary standards in all her writing projects. With her creative skills and technical understanding, she is able to create engaging and informative content that resonates with her audience.

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