1. What is AWS and why is it widely used? #

Answer:
AWS (Amazon Web Services) is a comprehensive cloud platform provided by Amazon. It offers on-demand computing resources, storage, databases, and other services. It is widely used because of its scalability, pay-as-you-go pricing, global reach, and extensive ecosystem of services.

2. What are the main components of AWS? #

Answer:

  • Compute: EC2, Lambda, Elastic Beanstalk
  • Storage: S3, EBS, Glacier
  • Databases: RDS, DynamoDB, Redshift
  • Networking: VPC, Route 53, ELB
  • Security: IAM, Shield, WAF

3. What is the difference between S3 and EBS? #

Answer:

  • S3: Object storage for unstructured data; scalable and used for backup, archive, and media storage.
  • EBS: Block storage attached to EC2 instances for persistent data storage, similar to hard drives.

4. Explain what an EC2 instance is. #

Answer:
EC2 (Elastic Compute Cloud) is a virtual server in AWS that can be scaled to handle different workloads. You can select instance types, operating systems, and configurations based on requirements.

5. What is IAM and why is it important? #

Answer:
IAM (Identity and Access Management) allows you to manage users and permissions in AWS. It is crucial for controlling access to resources, implementing least-privilege principles, and ensuring security.

6. What are Amazon RDS and DynamoDB, and how do they differ? #

Answer:

  • RDS: Relational Database Service for structured data, supporting SQL-based databases like MySQL, PostgreSQL, and Oracle.
  • DynamoDB: NoSQL database for unstructured data, highly scalable, and designed for low-latency applications.

7. What is Auto Scaling? #

Answer:
Auto Scaling adjusts the number of EC2 instances in response to traffic or demand automatically, ensuring availability and cost-efficiency.

8. What is CloudFormation? #

Answer:
AWS CloudFormation allows you to define and provision infrastructure as code (IaC) using JSON or YAML templates. It automates resource creation and configuration.

9. What is the purpose of AWS VPC? #

Answer:
VPC (Virtual Private Cloud) lets you create isolated networks within AWS to securely host resources like EC2 instances. It includes subnets, route tables, and security groups.

10. How does Elastic Load Balancer (ELB) work? #

Answer:
ELB automatically distributes incoming traffic across multiple targets (EC2, containers) to improve application availability and fault tolerance.

11. What is the difference between CloudWatch and CloudTrail? #

Answer:

  • CloudWatch: Monitoring and observability service for metrics like CPU usage, disk I/O, and application logs.
  • CloudTrail: Tracks API calls and actions across AWS services for auditing and compliance.

12. What is S3 bucket versioning? #

Answer:
Versioning in S3 keeps multiple versions of objects in a bucket. It protects data against accidental deletions or overwrites.

13. What is Route 53? #

Answer:
Route 53 is AWS's scalable DNS web service. It routes end users to internet applications and supports domain registration, DNS management, and health checks.

14. How does AWS Lambda work? #

Answer:
AWS Lambda is a serverless compute service that automatically runs your code in response to events. You pay only for the compute time consumed.

15. What is the Shared Responsibility Model? #

Answer:
AWS handles security of the cloud (hardware, infrastructure). Customers handle security in the cloud (data encryption, IAM policies).

16. What is an Availability Zone (AZ)? #

Answer:
An AZ is a physically isolated data center within an AWS region, offering redundancy and fault isolation.

17. How do you secure data in transit and at rest in AWS? #

Answer:

  • In Transit: Use HTTPS, SSL/TLS, or AWS Certificate Manager.
  • At Rest: Use encryption (e.g., S3 server-side encryption, EBS encryption, KMS).

18. What is AWS EKS? #

Answer:
Amazon Elastic Kubernetes Service (EKS) is a managed Kubernetes service for deploying, managing, and scaling containerized applications.

19. What is AWS Snowball? #

Answer:
AWS Snowball is a data transfer service to move large amounts of data (petabytes) between your data center and AWS using physical storage devices.

20. What is the difference between Spot Instances and Reserved Instances? #

Answer:

  • Spot Instances: Discounted EC2 capacity suitable for flexible, non-critical workloads.
  • Reserved Instances: Pre-purchased EC2 capacity at a lower price, used for predictable workloads.