AWS Interview Questions and Answers
For AWS interviews, tailor your preparation to your experience level. Freshers should review basic AWS interview questions and answers, with PDFs available for free download. Experienced candidates should focus on scenario-based questions, including those specific to AWS EC2. Java developers should prepare for AWS interview questions related to integrating AWS services with Java applications. Comprehensive prep across these areas will help you excel in your AWS interview.
What is Amazon EC2?
Amazon EC2 (Elastic Compute Cloud) is a scalable virtual server service in AWS. It allows you to rent virtual machines, known as instances, to run applications.
Example: A company running a web application for e-commerce uses EC2 instances to scale their server capacity during high traffic events, such as Black Friday sales, to handle increased user demand.
2. What is Amazon S3?
Amazon S3 (Simple Storage Service) is an object storage service that provides scalable, high-speed, and secure storage for data.
Example: A media company stores large video files in S3, allowing them to distribute content to global users with high availability and low latency through integrations with their content delivery network.
3. What is AWS Lambda?
AWS Lambda is a serverless compute service that executes code in response to events without provisioning or managing servers.
Example: An online retailer uses Lambda to automatically update inventory levels in their database when new stock is received or when orders are placed, triggered by events from their inventory management system.
4. What is Amazon RDS?
Amazon RDS (Relational Database Service) is a managed database service that supports various database engines, including MySQL, PostgreSQL, and SQL Server.
Example: A SaaS provider uses Amazon RDS to host a PostgreSQL database for their application, benefiting from automated backups, scaling, and high availability features.
5. What is Amazon VPC?
Amazon VPC (Virtual Private Cloud) allows you to create a private network within AWS, providing control over IP addresses, subnets, and network configurations.
Example: A financial institution sets up a VPC to host their application servers and databases, ensuring sensitive data remains isolated and secure from public access.
6. What are IAM Roles?
IAM Roles are AWS identities with specific permissions that can be assumed by users, applications, or services.
Example: An application running on an EC2 instance assumes an IAM Role to securely access an S3 bucket for retrieving and storing configuration files without embedding credentials in the code.
7. What is Amazon CloudWatch?
Amazon CloudWatch is a monitoring service that provides data and insights into AWS resources and applications, including metrics and logs.
Example: A company uses CloudWatch to monitor the performance of their EC2 instances, setting up alarms to notify administrators if CPU utilization exceeds a critical threshold, ensuring they can respond promptly to potential issues.
8. What is Amazon DynamoDB?
Amazon DynamoDB is a fully managed NoSQL database service that provides fast and predictable performance with seamless scalability.
Example: An online gaming company uses DynamoDB to handle high-velocity user data, such as player scores and session states, allowing for quick lookups and updates during live gameplay.
9. What is AWS Elastic Beanstalk?
AWS Elastic Beanstalk is a PaaS that simplifies deploying, managing, and scaling applications by handling the infrastructure for you.
Example: A startup uses Elastic Beanstalk to deploy their Node.js web application, allowing them to focus on code development while AWS handles scaling, load balancing, and application monitoring.
10. What is AWS CloudFormation?
AWS CloudFormation is a service that allows you to define and provision AWS infrastructure using code in JSON or YAML format.
Example: A large enterprise uses CloudFormation templates to automate the deployment of their entire infrastructure stack, including VPCs, EC2 instances, and RDS databases, ensuring consistent and repeatable setups across multiple environments.
11. How does AWS Auto Scaling work?
AWS Auto Scaling adjusts the number of EC2 instances in your application based on demand, ensuring optimal performance and cost-efficiency.
Example: An e-commerce website uses Auto Scaling to automatically add more EC2 instances during peak shopping seasons and scale down after the busy period, optimizing cost while maintaining performance.
12. What is an Amazon S3 bucket policy?
An S3 bucket policy is a JSON-based policy that specifies permissions for accessing S3 buckets and objects.
Example: An organization uses an S3 bucket policy to grant read-only access to their data warehouse team, allowing them to access specific datasets for analysis while preventing unauthorized modifications.
13. What is the difference between EBS and EFS?
Amazon EBS (Elastic Block Store) provides block storage for EC2 instances, while Amazon EFS (Elastic File System) offers scalable file storage that can be shared among multiple instances.
Example: A content management system uses EBS for storing application data on individual EC2 instances, while EFS is used to share media files across multiple instances in a web application cluster.
14. What is AWS Elastic Load Balancing (ELB)?
AWS ELB distributes incoming traffic across multiple EC2 instances to ensure high availability and reliability.
Example: A global online retailer uses ELB to distribute incoming web traffic to their EC2 instances in multiple regions, ensuring that their website remains responsive even during high traffic periods.
15. How do you secure data in Amazon S3?
You can secure S3 data using bucket policies, IAM policies, encryption (SSE), and access control lists (ACLs).
Example: A healthcare provider uses server-side encryption with AWS KMS to encrypt sensitive patient data stored in S3 buckets, ensuring compliance with data protection regulations.
16. What is Amazon CloudFront?
Amazon CloudFront is a content delivery network (CDN) service that caches and delivers content from edge locations to improve performance and reduce latency.
Example: A media streaming service uses CloudFront to cache and deliver video content to users worldwide, reducing latency and improving the viewing experience.
17. What is a Security Group in AWS?
A Security Group acts as a virtual firewall for EC2 instances, controlling inbound and outbound traffic based on defined rules.
Example: A company sets up a Security Group to allow HTTP and HTTPS traffic to their web server instances while blocking all other inbound traffic, enhancing the security of their application.
18. What is the purpose of AWS IAM policies?
IAM policies define permissions for users, roles, and groups to control access to AWS resources.
Example: An organization creates an IAM policy to grant a development team read-write access to their S3 buckets while restricting other teams to read-only access.
19. What is AWS CodeDeploy?
AWS CodeDeploy is a deployment service that automates application deployments to various compute services such as EC2, Lambda, and on-premises servers.
Example: A software company uses CodeDeploy to automate the deployment of new application versions to their EC2 instances, reducing downtime and ensuring consistent updates.
20. What is AWS Trusted Advisor?
AWS Trusted Advisor provides recommendations to help you follow best practices for AWS resource configurations and optimize your AWS environment.
Example: A business uses Trusted Advisor to identify underutilized EC2 instances and receive recommendations for cost savings by downsizing or terminating excess instances.
21. What is AWS CloudTrail and what is it used for?
AWS CloudTrail is a service that enables governance, compliance, and auditing of AWS account activity by logging API calls made on your account.
Example: A financial institution uses CloudTrail to track and audit changes to their IAM policies and EC2 instance configurations, ensuring compliance with security policies.
22. How does AWS Direct Connect work?
AWS Direct Connect provides a dedicated network connection from your premises to AWS, offering a more consistent network experience compared to the internet.
Example: A multinational corporation uses Direct Connect to establish a private, high-bandwidth connection between their data centers and AWS, facilitating faster and more reliable data transfers.
23. What is Amazon Aurora?
Amazon Aurora is a fully managed relational database engine compatible with MySQL and PostgreSQL, designed for high performance and availability.
Example: An online gaming company uses Amazon Aurora to manage its high-traffic gaming database, benefiting from Aurora’s high availability and automatic failover features.
24. What is AWS Lambda Edge?
AWS Lambda Edge allows you to run Lambda functions at AWS CloudFront edge locations, enabling you to customize content delivery and perform actions closer to your users.
Example: An e-commerce website uses Lambda@Edge to personalize content based on the user’s geographic location, providing region-specific offers and improving the user experience.
25. How do you manage secrets in AWS?
AWS Secrets Manager and AWS Systems Manager Parameter Store are services used to securely store and manage secrets such as API keys and database credentials.
Example: A development team stores their database credentials in AWS Secrets Manager, allowing their application to securely retrieve and use the credentials without hardcoding them.
26. What is Amazon EKS?
Amazon EKS (Elastic Kubernetes Service) is a managed service that simplifies running Kubernetes clusters on AWS.
Example: A DevOps team uses Amazon EKS to deploy and manage a containerized application, benefiting from managed control plane and integration with other AWS services.
27. How does AWS handle high availability?
AWS provides high availability through multiple Availability Zones within regions, offering redundancy and fault tolerance for applications.
Example: A financial application is deployed across multiple Availability Zones to ensure that it remains operational even if one zone experiences an outage, thus maintaining service continuity.
28. What is AWS Global Accelerator?
AWS Global Accelerator improves the availability and performance of your applications by directing traffic through AWS’s global network infrastructure.
Example: A global SaaS application uses Global Accelerator to improve latency and availability by routing user traffic to the nearest AWS edge location.
29. What is AWS Service Catalog?
AWS Service Catalog allows organizations to create and manage approved catalogs of AWS resources and services, providing a self-service portal for users.
Example: An enterprise creates a Service Catalog for its development teams, providing pre-approved templates for deploying compliant infrastructure resources, such as VPCs and RDS instances.
30. How do you perform data migration to AWS?
Data migration to AWS can be performed using services such as AWS Database Migration Service (DMS), AWS Snowball, or AWS DataSync.
Example: A company uses AWS Snowball to transfer large volumes of data from their on-premises data center to Amazon S3, accelerating the migration process and reducing network transfer times.
31. What is Amazon Route 53?
Amazon Route 53 is a scalable DNS and domain name registration service that provides reliable routing of end-user requests to AWS resources.
Example: A website uses Route 53 to manage DNS records for its domain and route traffic to different AWS resources, such as an S3 bucket for static content and an EC2 instance for dynamic content.
32. What is AWS Config?
AWS Config is a service that provides AWS resource configuration tracking and compliance auditing to help manage and monitor AWS resources.
Example: An organization uses AWS Config to monitor and ensure that their EC2 instances comply with security best practices, such as correct tagging and appropriate security group settings.
33. How do you implement a CI/CD pipeline on AWS?
Implement a CI/CD pipeline using AWS services like AWS CodePipeline, CodeBuild, and CodeDeploy to automate the build, test, and deployment processes.
Example: A development team sets up a CI/CD pipeline using CodePipeline to automatically build and deploy application code changes to EC2 instances, reducing manual intervention and accelerating release cycles.
34. What is AWS Fargate?
AWS Fargate is a serverless compute engine for containers that works with Amazon ECS and EKS, allowing you to run containers without managing servers.
Example: A company deploys its microservices architecture using Fargate, allowing them to run containerized applications without managing the underlying EC2 instances.
35. What is Amazon Redshift?
Amazon Redshift is a fully managed data warehouse service that provides fast query performance using SQL-based tools and standard JDBC/ODBC drivers.
Example: A retail company uses Amazon Redshift to analyze large volumes of sales data, enabling them to generate complex reports and insights for business intelligence.
36. What are AWS Spot Instances?
AWS Spot Instances allow you to purchase unused EC2 capacity at a lower price compared to On-Demand instances, with the risk of interruption.
Example: A company uses Spot Instances for batch processing tasks, taking advantage of lower costs while being prepared for potential interruptions.
37. What is AWS Glue?
AWS Glue is a fully managed ETL (extract, transform, load) service that makes it easy to prepare and load data for analytics.
Example: A data analyst uses AWS Glue to transform raw log data into a structured format before loading it into Amazon Redshift for querying and analysis.
38. What is Amazon QuickSight?
Amazon QuickSight is a business analytics service that provides interactive visualizations and insights from your data.
Example: A marketing team uses QuickSight to create dashboards and visualizations from sales data, allowing them to track campaign performance and make data-driven decisions.
39. What is AWS CodeStar?
AWS CodeStar is a cloud-based development platform that enables you to develop, build, and deploy applications on AWS.
Example: A development team uses AWS CodeStar to streamline their software development workflow, integrating with CodePipeline, CodeBuild, and CodeDeploy for a complete CI/CD solution.
40. What is AWS Systems Manager?
AWS Systems Manager is a management service that provides visibility and control of your AWS infrastructure and applications.
Example: An operations team uses Systems Manager to automate patch management and configuration tasks across their fleet of EC2 instances, improving operational efficiency.
41. What is Amazon ECR?
Amazon ECR (Elastic Container Registry) is a fully managed Docker container registry that makes it easy to store, manage, and deploy Docker container images.
Example: A DevOps team uses ECR to store Docker images for their microservices, integrating it with ECS or EKS for streamlined container deployment.
42. What is AWS Organizations?
AWS Organizations is a service that allows you to manage multiple AWS accounts centrally, applying policies and controls across your organization.
Example: A large enterprise uses AWS Organizations to manage billing and apply service control policies across multiple accounts for different departments and projects.
43. What is AWS Backup?
AWS Backup is a fully managed backup service that automates and centrally manages backups across AWS services.
Example: A business uses AWS Backup to automate the backup and retention of critical data from RDS, EFS, and DynamoDB, ensuring compliance with data protection regulations.
44. What is AWS Transit Gateway?
AWS Transit Gateway is a service that enables you to connect multiple VPCs and on-premises networks through a single gateway.
Example: An enterprise uses AWS Transit Gateway to simplify the network architecture by connecting multiple VPCs and their on-premises data center, facilitating inter-network communication.
45. What is AWS WAF?
AWS WAF (Web Application Firewall) helps protect your web applications from common web exploits and vulnerabilities.
Example: A company uses AWS WAF to block SQL injection attacks and cross-site scripting (XSS) attempts on their application hosted on Amazon CloudFront.
46. What is Amazon Kinesis?
Amazon Kinesis is a platform for real-time data streaming and analytics, allowing you to process and analyze streaming data at scale.
Example: A social media company uses Amazon Kinesis to analyze and process real-time user interaction data, enabling them to provide live analytics and personalized content.
47. What is Amazon Elasticsearch Service?
Amazon Elasticsearch Service provides a managed service for deploying and scaling Elasticsearch clusters for search, logging, and analytics use cases.
Example: A tech company uses Elasticsearch Service to provide full-text search capabilities on their website and analyze log data for operational insights.
48. What is AWS Shield?
AWS Shield is a managed DDoS protection service that safeguards applications against Distributed Denial of Service (DDoS) attacks.
Example: A financial services provider uses AWS Shield Advanced to protect their online banking application from potential DDoS attacks, ensuring service availability and resilience.
49. What is AWS FMS?
AWS Firewall Manager (FMS) is a security management service that helps you centrally configure and manage firewall rules across your AWS accounts.
Example: A large organization uses AWS FMS to enforce consistent security group rules and network firewall policies across multiple AWS accounts and VPCs.
50. What is AWS Snowball?
AWS Snowball is a data transfer service that uses secure appliances to transfer large amounts of data to and from AWS.
Example: A company uses AWS Snowball to migrate large volumes of data from their on-premises storage to Amazon S3, speeding up the data transfer process and reducing network bandwidth usage.