Interview questions

AWS Developer

Here is a set of AWS Developer interview questions that can aid in identifying the most qualified candidates possessing iOS development skills, suitable for developing mobile applications.

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Amazon Web Services (AWS) is a comprehensive cloud computing platform provided by Amazon. It offers a wide range of cloud services, including computing power, storage, and databases, as well as analytics, networking, and developer tools. AWS provides scalable and flexible solutions that enable businesses to build and deploy applications and services with ease. With a global infrastructure and a pay-as-you-go pricing model, AWS empowers organizations to leverage the cloud to enhance their agility, scalability, and cost-efficiency.


What is an Elastic Load Balancer in AWS and how does it work?

Elastic Load Balancer (ELB) is a service in AWS that distributes incoming application traffic across multiple EC2 instances to improve availability and fault tolerance. There are three types of ELB: Classic Load Balancer, Application Load Balancer, and Network Load Balancer. ELBs automatically scale in response to incoming traffic and distribute the load to healthy instances. They also perform health checks to ensure that only healthy instances receive traffic.

How can you secure data at rest in Amazon S3?

Data at rest in Amazon S3 can be secured using server-side encryption. There are three options for server-side encryption: SSE-S3 (using Amazon S3 managed keys), SSE-KMS (using AWS Key Management Service), and SSE-C (using customer-provided keys). These encryption methods help protect data stored in S3 from unauthorized access.

What is the difference between Amazon RDS and Amazon DynamoDB?

Amazon RDS (Relational Database Service) is a managed database service that provides a relational database, such as MySQL, PostgreSQL, or Oracle, in the cloud. It handles routine database management tasks, such as backups, patching, and replication.

What are the benefits of using Amazon CloudFront?

Amazon CloudFront is a content delivery network (CDN) service that accelerates the delivery of web content to users worldwide. The benefits of using CloudFront include reduced latency and improved performance, enhanced security through integration with AWS Web Application Firewall (WAF), easy integration with other AWS services, and cost optimization by reducing the load on origin servers.

How does AWS Lambda work?

AWS Lambda is a serverless compute service that allows you to run code without provisioning or managing servers. It follows an event-driven architecture, where you define a Lambda function and associate it with an event source, such as an API Gateway request, an S3 bucket upload, or a CloudWatch event. When the event occurs, Lambda automatically executes the function and charges you only for the compute time consumed.

How would you troubleshoot high CPU utilization on an EC2 instance?

To troubleshoot high CPU utilization on an EC2 instance, I would start by checking the CloudWatch metrics for the instance to identify the specific time periods and patterns of high CPU usage. Then, I would analyze the system and application logs to identify any processes or services consuming excessive CPU resources. Additionally, I would consider resizing or scaling the instance to handle the increased load and optimize the application code or configuration to reduce CPU usage.

Imagine a scenario where an EC2 instance fails to start after a reboot. How would you approach this issue?

If an EC2 instance fails to start after a reboot, I would first check the system and instance status checks in the EC2 console to identify any reported issues. If there are any failed status checks, I would investigate the underlying causes, such as insufficient disk space, security group misconfiguration, or issues with the instance's operating system. I would also review the instance's logs and console output to gather more information about the failure. Based on the findings, I would take appropriate actions, such as modifying the instance's configuration, performing instance recovery, or launching a new instance.

How would you ensure data durability and availability in Amazon S3?

To ensure data durability and availability in Amazon S3, I would enable versioning on the S3 bucket to protect against accidental deletion or overwrites. I would also enable cross-region replication (CRR) to replicate the data to a different AWS region for disaster recovery purposes. Additionally, I would set up lifecycle policies to automatically transition objects to lower-cost storage classes as they age, ensuring cost optimization while maintaining accessibility.

What steps would you take to secure an AWS account?

To secure an AWS account, I would implement multi-factor authentication (MFA) for all IAM users and enforce strong password policies. I would regularly review and audit IAM roles, policies, and permissions to ensure least privilege access. Enabling AWS CloudTrail for logging and monitoring changes to the account is crucial. I would also apply security best practices such as encrypting sensitive data, regularly patching and updating AWS resources, and using AWS Identity and Access Management (IAM) roles instead of using access keys.

Describe the process of deploying a scalable and fault-tolerant application on AWS.

Deploying a scalable and fault-tolerant application on AWS involves several steps. First, I would design the architecture using services like EC2, Auto Scaling, and Elastic Load Balancing to distribute traffic across multiple instances and scale based on demand. I would use Amazon RDS or DynamoDB for reliable and scalable data storage. Next, I would leverage AWS CloudFormation or AWS Elastic Beanstalk to automate the deployment process. I would also incorporate monitoring and alerting using CloudWatch to ensure system health and performance. Finally, I would regularly test the application's resilience by simulating failures and performing load testing to ensure it can handle increased traffic and maintain availability.

Can you describe a time when you had to work on a challenging project or task with tight deadlines? How did you handle it?

In a challenging project with tight deadlines, I prioritized tasks based on their criticality and created a detailed plan with milestones and deliverables. I communicated with the team to set clear expectations and ensure everyone was aware of the timeline. I delegated tasks to team members based on their strengths and provided support and guidance throughout the project. By staying focused, managing time effectively, and fostering open communication, we successfully met the deadlines and delivered the project on time.

Tell me about a situation where you encountered a difficult technical problem. How did you approach it, and what was the outcome?

When facing a difficult technical problem, I first conducted thorough research and analysis to gain a deep understanding of the issue. I consulted relevant documentation, forums, and colleagues to gather insights and potential solutions. I approached the problem systematically, breaking it down into smaller components and tackling each one individually. I experimented with different approaches and conducted tests to validate potential solutions. Through persistence and collaboration, I eventually identified and resolved the problem, achieving the desired outcome.

Tell me about a time when you had to troubleshoot a complex issue in an AWS environment. How did you approach it, and what was the outcome?

IThe candidate should describe a specific incident where they encountered a complex issue in an AWS environment. They should explain their troubleshooting approach, such as analyzing logs, utilizing AWS monitoring tools, or collaborating with team members. The candidate's answer should demonstrate their problem-solving skills, technical expertise, and ability to resolve issues effectively.

Describe a situation where you had to prioritize tasks and meet tight deadlines while working on an AWS project. How did you manage your time, and what was the result?

The candidate should share an experience where they had multiple tasks to complete within a limited timeframe in an AWS project. They should explain their approach to prioritize tasks, such as setting clear goals, breaking down the work into smaller manageable tasks, and effectively managing their time. The candidate's answer should demonstrate their ability to work under pressure, prioritize effectively, and deliver results within deadlines.