AWS interview questions for Infosys

AWS interview questions for Infosys with expla

AWS interview questions and answers at Infosys requires a comprehensive understanding of various AWS services, their functionalities, and best practices. Below is a curated list of 30 commonly asked AWS interview questions along with concise answers to help you prepare effectively:

1. What is AWS ? Explain its key services.

AWS (Amazon Web Services) is a cloud computing platform offering IaaS, PaaS, and SaaS solutions. Key services include:

Compute: EC2, Lambda
Storage: S3, EBS
Databases: RDS, DynamoDB
Networking: VPC, CloudFront
Security: IAM, KMS

2. What is EC2 ? Explain its pricing models.

EC2 (Elastic Compute Cloud) provides scalable virtual servers in the cloud.

Pricing Models:

On-Demand: Pay-per-use, no commitments.
Reserved: 1- or 3-year commitment for discounts.
Spot Instances: Bidding-based, cheaper but can be terminated.
Dedicated Hosts: Physical server for compliance needs.

3. What is S3 ? Explain storage classes.

S3 (Simple Storage Service) is object storage for unstructured data.

Storage Classes:

Standard: High availability (99.99%).
IA (Infrequent Access): Cheaper, used for less frequent access.
Glacier: Archive storage, retrieval takes time.
Intelligent-Tiering: Auto-moves data between Standard & IA.

4. What is IAM ? Explain roles, policies, and groups.

IAM (Identity and Access Management) controls user permissions in AWS.

Roles: Temporary permissions for AWS services.
Policies: JSON-based rules granting/restricting access.
Groups: Collection of users with shared policies.

5. What is a VPC ? How does it enhance security ?

VPC (Virtual Private Cloud) allows users to launch AWS resources in an isolated network.

Security Features:

Subnets: Private and Public segregation.
Security Groups & NACLs: Firewall for inbound/outbound traffic.
VPN & Direct Connect: Secure hybrid cloud connectivity.

6. What is AWS Lambda ? How does it differ from EC2 ?

AWS Lambda is a serverless compute service that runs code without provisioning servers.

Difference from EC2:

No infrastructure management in Lambda, EC2 needs instance setup.
Auto-scales automatically, EC2 needs manual scaling.
Billing: Lambda is per-execution; EC2 is hourly.

7. What is Auto Scaling ? Explain Scaling Policies.

Auto Scaling ensures applications run efficiently by automatically adjusting EC2 instances.

Scaling Policies:

Dynamic Scaling: Adds/removes instances based on demand.
Scheduled Scaling: Predetermined increase/decrease at specific times.
Predictive Scaling: Uses machine learning to anticipate traffic patterns.

8. What is Route 53 ? Explain Routing Policies.

Route 53 is AWS’s DNS service for domain name resolution.

Routing Policies:

Simple: Single record resolution.
Weighted: Traffic distribution based on assigned weights.
Latency-Based: Routes to lowest-latency region.
Failover: Redirects traffic if the primary fails.

9. What is an Elastic Load Balancer (ELB) ? Explain types.

ELB distributes incoming traffic across multiple targets.

Types of ELB:

Classic Load Balancer (CLB): Basic L4/L7 routing.
Application Load Balancer (ALB): HTTP-based, routes by request path.
Network Load Balancer (NLB): High-performance L4 routing.

10. What is AWS CloudFront ? Explain its benefits.

CloudFront is AWS’s Content Delivery Network (CDN).

Benefits:

Caches content globally for fast access.
Reduces latency & improves speed.
Enhances security via AWS Shield.

11. What is CloudWatch ? How does it differ from CloudTrail ?

CloudWatch is AWS’s monitoring service for logs, metrics, and alarms.

Difference from CloudTrail:

CloudWatch: Monitors performance metrics.
CloudTrail: Logs API calls & user activity for auditing.

SNS (Simple Notification Service): Push messaging system (email, SMS, Lambda).
SQS (Simple Queue Service): Queue-based message system ensuring asynchronous processing.
Difference: SNS is pub/sub, while SQS is message queue-based.

13. What is AWS EBS ? How is it different from S3 ?

EBS (Elastic Block Store) is persistent storage for EC2.

Difference from S3:

EBS: Block storage, requires an EC2 instance.
S3: Object storage, used for large-scale data.

14. What is AWS RDS ? Explain its benefits.

RDS (Relational Database Service) is managed database for SQL-based engines (MySQL, PostgreSQL).

Benefits:

Automated Backups
Multi-AZ Deployment for High Availability
Read Replicas for Performance

15. What is AWS DynamoDB ? How is it different from RDS ?

DynamoDB is a fully managed NoSQL database.

Difference from RDS:

DynamoDB: NoSQL (key-value), scales automatically.
RDS: SQL-based, requires scaling configurations.

16. Explain the relationship between an instance and AMI.

An AMI serves as the blueprint for an instance; multiple instances can be launched from a single AMI.

17. What is AWS IAM ?

AWS Identity and Access Management (IAM) enables you to manage access to AWS services and resources securely.

18. What is Amazon VPC ?

Amazon Virtual Private Cloud (VPC) allows users to provision a logically isolated section of the AWS cloud to launch resources in a virtual network.

19. What is an AMI ?

An Amazon Machine Image (AMI) is a template that contains the software configuration (operating system, application server, and applications) required to launch an instance.

20. Explain the relationship between an instance and AMI.

An Amazon Machine Image (AMI) is a template that contains the software configuration (operating system, application server, and applications) required to launch an instance.

21. What is Amazon SNS ?

Amazon Simple Notification Service (SNS) is a fully managed messaging service for both application-to-application (A2A) and application-to-person (A2P) communication.

22. What is AWS CloudFormation ?

AWS CloudFormation provides a common language for describing and provisioning all the infrastructure resources in your cloud environment.

23. What is Amazon Redshift ?

Amazon Redshift is a fully managed data warehouse service that allows for fast querying and analysis of large datasets.

24. What is Amazon Elastic Beanstalk ?

AWS Elastic Beanstalk is an easy-to-use service for deploying and scaling web applications and services.

25.What is AWS OpsWorks ?

AWS OpsWorks is a configuration management service that provides managed instances of Chef and Puppet. It allows you to automate how servers are configured, deployed, and managed across your Amazon EC2 instances or on-premises compute environments.

26. What is Amazon Kinesis ?

AWS Elastic Beanstalk is an easy-to-use service for deploying and scaling web applications and services.

27. What is AWS Glue ?

AWS Glue is a fully managed extract, transform, and load (ETL) service that makes it easy to prepare and load data for analytics. It simplifies and automates the difficult and time-consuming tasks of data discovery, conversion, mapping, and job scheduling.

28. What is Amazon Athena ?

Amazon Athena is an interactive query service that makes it easy to analyze data in Amazon S3 using standard SQL. It is serverless, so there is no infrastructure to manage, and you pay only for the queries that you run.

29. Explain the concept of AWS Lambda Layers.

AWS Lambda Layers allow you to package and distribute libraries, custom runtimes, and other dependencies separately from your function code. This promotes code reuse, reduces deployment package sizes, and simplifies the management of shared components across multiple functions

30. What is AWS Auto Scaling ?

AWS Auto Scaling monitors your applications and automatically adjusts capacity to maintain steady, predictable performance at the lowest possible cost.

AWS interview questions for Infosys