Basic Questions

1. What is AWS?
   • Answer: AWS (Amazon Web Services) is a comprehensive and widely adopted cloud platform offering over 200 fully featured services from data centers globally.
2. What are the main components of AWS?
   • Answer: The main components include Compute (EC2, Lambda), Storage (S3, EBS), Databases (RDS, DynamoDB), Networking (VPC, Route 53), and Management tools (CloudWatch, CloudFormation).
3. What is EC2?
   • Answer: Amazon EC2 (Elastic Compute Cloud) is a web service that provides resizable compute capacity in the cloud, allowing users to run virtual servers.
4. What is S3?
   • Answer: Amazon S3 (Simple Storage Service) is a scalable object storage service used for storing and retrieving any amount of data at any time.
5. What is an AMI?
   • Answer: An Amazon Machine Image (AMI) is a template that contains the software configuration (OS, application server, and applications) required to launch an EC2 instance.

Intermediate Questions

6. What is a VPC?
   • Answer: Amazon VPC (Virtual Private Cloud) lets you provision a logically isolated section of the AWS cloud where you can launch AWS resources in a virtual network.
7. What is IAM?
   • Answer: AWS Identity and Access Management (IAM) is a service that helps you control access to AWS resources securely.
8. What are Security Groups?
   • Answer: Security Groups act as virtual firewalls for your EC2 instances to control incoming and outgoing traffic.
9. What is Auto Scaling?
   • Answer: Auto Scaling ensures you have the right number of EC2 instances available to handle the load for your application by scaling up or down automatically based on predefined conditions.
10. What is Elastic Load Balancing (ELB)?
    • Answer: ELB automatically distributes incoming application traffic across multiple targets, such as EC2 instances, containers, and IP addresses.

Advanced Questions

11. What is CloudFormation?
    • Answer: AWS CloudFormation is a service that helps you model and set up your AWS resources so you can spend less time managing those resources and more time focusing on your applications.
12. What is AWS Lambda?
    • Answer: AWS Lambda is a serverless compute service that lets you run code without provisioning or managing servers, scaling automatically based on the workload.
13. What is Route 53?
    • Answer: Amazon Route 53 is a scalable and highly available Domain Name System (DNS) web service.
14. What is DynamoDB?
    • Answer: Amazon DynamoDB is a fast and flexible NoSQL database service for all applications that need consistent, single-digit millisecond latency at any scale.
15. What is AWS RDS?
    • Answer: Amazon Relational Database Service (RDS) makes it easy to set up, operate, and scale a relational database in the cloud.

Scenario-Based Questions

16. How do you secure data at rest and in transit in AWS?
    • Answer: Secure data at rest using encryption services like AWS KMS, and secure data in transit using SSL/TLS protocols.
17. How would you set up a VPC with public and private subnets?
    • Answer: Create a VPC, then create subnets within the VPC. Assign a public subnet with an Internet Gateway for public-facing resources and a private subnet with a NAT Gateway for internal resources.
18. How do you manage disaster recovery (DR) in AWS?
    • Answer: Implement DR strategies like backup and restore, pilot light, warm standby, and multi-site active/active, using services like S3 for backups, RDS for database snapshots, and Route 53 for DNS failover.
19. How do you migrate an on-premises application to AWS?
    • Answer: Assess the application and infrastructure, plan the migration strategy (lift and shift, re-platform, etc.), use AWS migration tools like AWS Database Migration Service (DMS) and AWS Server Migration Service (SMS), and validate the migration.
20. How do you monitor AWS resources and applications?
    • Answer: Use AWS CloudWatch to collect and track metrics, collect and monitor log files, and set alarms. Use CloudTrail for logging and monitoring API calls.
21. Explain how you would set up a highly available and scalable web application in AWS.
    • Answer: Use EC2 instances behind an ELB, spread across multiple Availability Zones for high availability. Use Auto Scaling to handle scaling, RDS in Multi-AZ for the database, and S3 for static content.
22. How do you implement CI/CD in AWS?
    • Answer: Use AWS CodePipeline for continuous integration and delivery, AWS CodeBuild for build services, AWS CodeDeploy for deployment automation, and integrate with other services like GitHub or AWS CodeCommit for source control.
23. How do you optimize the cost of running an application in AWS?
    • Answer: Right-size instances, use Reserved Instances and Savings Plans, leverage Auto Scaling, use spot instances for non-critical workloads, and monitor usage with AWS Cost Explorer and Trusted Advisor.
24. How do you handle cross-account access in AWS?
    • Answer: Use IAM roles with cross-account trust policies and assume role permissions to grant access between different AWS accounts.
25. Explain the difference between S3, EBS, and EFS.
    • Answer: S3 is object storage for scalable data storage, EBS provides block storage for use with EC2, and EFS offers scalable file storage for use with multiple EC2 instances.

Deep Dive Questions

26. What are the different types of storage gateways in AWS?
    • Answer: The types are File Gateway (NFS/SMB), Volume Gateway (cached and stored volumes), and Tape Gateway (VTL).
27. How do you implement network segmentation in AWS?
    • Answer: Use VPCs, subnets, security groups, and network ACLs to create isolated network segments. Implement private subnets for internal resources and public subnets for external-facing resources.
28. What are the best practices for securing your AWS account?
    • Answer: Enable multi-factor authentication (MFA), use IAM roles instead of root account access, enforce strong password policies, use AWS Organizations for multi-account management, and regularly review IAM policies.
29. Explain the Shared Responsibility Model in AWS.
    • Answer: AWS manages the security of the cloud (infrastructure, hardware, software), while customers are responsible for security in the cloud (data, applications, access management).
30. What is the use of AWS CloudTrail?
    • Answer: AWS CloudTrail enables governance, compliance, and operational and risk auditing of your AWS account by logging and monitoring API calls.

Advanced Questions

1. How do you implement multi-region deployments in AWS?
   • Answer: Use AWS services like Route 53 for DNS routing, S3 for cross-region replication, RDS for read replicas across regions, and Lambda@Edge for running code at AWS edge locations. Use CloudFormation StackSets to manage stacks across multiple regions.
2. Explain how you would implement a hybrid cloud architecture using AWS.
   • Answer: Use AWS Direct Connect or VPN to establish a secure connection between on-premises infrastructure and AWS. Use services like Storage Gateway for integrating on-premises storage with S3 and VPC peering or Transit Gateway for network connectivity between AWS VPCs and on-premises networks.
3. How do you handle application state in a serverless architecture on AWS?
   • Answer: Store state information in services like DynamoDB, S3, or RDS. Use Step Functions to manage workflow state and Lambda functions to handle stateless processing. For session management, use services like ElastiCache or DynamoDB.
4. Describe how you would design a secure API on AWS.
   • Answer: Use API Gateway to create and manage APIs, enable authorization using AWS IAM, Lambda authorizers, or Amazon Cognito, and secure data transmission with SSL/TLS. Implement logging and monitoring with CloudWatch, and enforce throttling and rate limiting.
5. What is AWS Service Control Policies (SCP), and how would you use them?
   • Answer: SCPs are policies that define the AWS service actions that can be used by entities in the AWS Organizations. Use SCPs to enforce compliance, security, and governance across multiple AWS accounts by allowing or denying specific actions.

Scenario-Based Questions

6. How would you set up a disaster recovery (DR) strategy for a critical application on AWS?
   • Answer: Choose a DR strategy based on RTO and RPO requirements (e.g., backup and restore, pilot light, warm standby, multi-site active/active). Use services like S3 for backups, RDS with Multi-AZ, Route 53 for DNS failover, and CloudFormation for infrastructure as code.
7. Describe a time when you had to troubleshoot a performance issue in an AWS environment. What steps did you take?
   • Answer: Provide an example such as troubleshooting latency issues in an EC2 instance. Use CloudWatch to monitor metrics, identify bottlenecks, check for resource utilization, analyze logs, and use tools like AWS X-Ray for tracing application performance.
8. How do you handle regulatory compliance requirements using AWS services?
   • Answer: Use AWS Artifact to access compliance reports, enable CloudTrail for logging API activity, use IAM to enforce least privilege access, encrypt data at rest and in transit with KMS, and implement security best practices as recommended by AWS Well-Architected Framework.
9. How would you migrate a database from an on-premises environment to AWS with minimal downtime?
   • Answer: Use AWS Database Migration Service (DMS) for continuous data replication. Create a replication instance, configure source and target endpoints, and start the migration task. Use RDS or DynamoDB as the target database, and cut over to the new database during a low-traffic period.
10. How do you optimize the cost of a data-intensive application running on AWS?
    • Answer: Use cost-effective storage solutions like S3 Glacier for archival data, enable S3 lifecycle policies to transition data to lower-cost storage tiers, use EC2 Spot Instances for non-critical workloads, implement Auto Scaling to match resource usage with demand, and use Cost Explorer for monitoring and analyzing spending.
11. Explain how you would design a scalable microservices architecture on AWS.
    • Answer: Use ECS or EKS for container orchestration, API Gateway for managing API endpoints, Lambda for serverless functions, and SQS or SNS for decoupling services. Implement service discovery with Route 53 or AWS App Mesh and use IAM for securing service-to-service communication.
12. How do you manage and deploy infrastructure as code (IaC) using AWS services?
    • Answer: Use AWS CloudFormation or Terraform for IaC. Write templates to define resources, manage versions in a source control system, use CI/CD pipelines for automated deployments, and validate configurations with tools like AWS Config and CloudFormation Drift Detection.
13. Describe a situation where you had to ensure high availability and fault tolerance for an application on AWS.
    • Answer: Provide an example such as designing a multi-tier application. Use ELB for load balancing, Auto Scaling for scaling EC2 instances, RDS with Multi-AZ for database availability, S3 for durable object storage, and Route 53 for DNS failover.
14. How do you implement security best practices for an AWS environment?
    • Answer: Use IAM to enforce the principle of least privilege, enable MFA for all users, use AWS Shield and WAF for protecting against DDoS attacks, enable CloudTrail for auditing, encrypt sensitive data using KMS, and regularly review security groups and network ACLs.
15. Explain how you would use AWS Glue and Athena for a data analytics pipeline.
    • Answer: Use AWS Glue to crawl data sources and create a data catalog, define ETL jobs to transform data, store transformed data in S3, and use Athena to run SQL queries on the data in S3. Leverage Glue triggers to automate ETL workflows and visualize results with QuickSight.
16. How do you handle logging and monitoring in AWS for a large-scale application?
    • Answer: Use CloudWatch for collecting and monitoring logs and metrics, set up CloudWatch Alarms for alerts, use CloudTrail for auditing API calls, enable VPC Flow Logs for network traffic analysis, and integrate with third-party tools like Splunk or ELK Stack for advanced log analysis.
17. What strategies would you use to secure a multi-account AWS environment?
    • Answer: Use AWS Organizations to manage multiple accounts, implement SCPs to enforce policies, use IAM roles for cross-account access, enable AWS CloudTrail and AWS Config for centralized logging and monitoring, and deploy GuardDuty for threat detection.
18. Describe how you would implement a CI/CD pipeline using AWS services.
    • Answer: Use AWS CodePipeline to orchestrate the CI/CD process, CodeCommit for source control, CodeBuild for building and testing code, CodeDeploy for deploying applications, and integrate with tools like CloudFormation or Terraform for infrastructure deployments.
19. How would you implement data encryption in AWS for compliance purposes?
    • Answer: Use KMS to manage encryption keys, enable encryption for S3 buckets, EBS volumes, and RDS instances, use SSL/TLS for data in transit, and ensure that all sensitive data is encrypted both at rest and in transit.
20. Explain how you would handle large-scale data ingestion and processing in AWS.
    • Answer: Use Kinesis Data Streams or Firehose for real-time data ingestion, AWS Glue or EMR for data processing, store processed data in S3 or Redshift, and use Athena or QuickSight for data analysis and visualization.
21. How do you design a cost-effective and scalable data storage solution on AWS?
    • Answer: Use S3 for object storage with lifecycle policies, Glacier for archival storage, EFS for scalable file storage, and RDS for relational database needs. Leverage S3 Intelligent-Tiering to optimize storage costs and use Reserved Instances or Savings Plans for predictable workloads.
22. Describe a time when you had to troubleshoot a network connectivity issue in AWS. What steps did you take?
    • Answer: Provide an example such as troubleshooting VPC connectivity. Use VPC Flow Logs to analyze traffic, check security group and network ACL configurations, verify route tables and NAT gateway setups, and use AWS CloudTrail to track API calls that might affect network configuration.
23. How do you ensure compliance with AWS best practices and frameworks?
    • Answer: Use AWS Well-Architected Tool to review workloads, implement AWS Config to monitor resource configurations, use Trusted Advisor for best practice recommendations, and regularly audit accounts with AWS Security Hub for compliance with standards like CIS and NIST.
24. How would you design a data pipeline for real-time analytics on AWS?
    • Answer: Use Kinesis Data Streams for real-time data ingestion, Lambda for processing and transformation, store processed data in S3 or DynamoDB, and use Athena or QuickSight for real-time data querying and visualization.
25. What is the significance of using tags in AWS, and how do you manage them effectively?
    • Answer: Tags are used for resource identification, organization, and cost allocation. Manage tags by enforcing tagging policies, using AWS Tag Editor for bulk tagging, and leveraging AWS Cost Explorer to track costs based on tags.