AWS Interview Questions Experienced

1. How would you design an architecture to handle applications which are experiencing unpredictable traffic spikes using AWS?

To dynamically adjust the number of EC2 instances, use Auto Scaling Groups (ASGs) based on traffic patterns. Configure a load balancer to distribute incoming traffic across instances. Set up CloudWatch Alarms to trigger scaling events based on request count.

To ensure traffic is only routed to healthy instances, enable Elastic Load Balancing (ELB) health checks. Use Amazon RDS with Read Replicas or DynamoDB to handle database traffic scaling.

2. What are VPC Peering and its limitations?

VPC Peering is a networking connection between two VPCs that allows traffic routing between them using private IPs.

Limitations of VPC Peering

No transitive peering (VPC A can’t connect to VPC C through VPC B).
No overlapping IP address ranges are allowed.
No centralized gateway for peered connections.

3. Explain the difference between S3 Standard, S3 IA (Infrequent Access), and Glacier.

S3 Standard: High availability and durability for frequently accessed data.
S3 Infrequent Access (IA): Lower-cost storage for data accessed less frequently but still requiring rapid access.
Glacier: Low-cost storage for long-term archival data that doesn’t require immediate access.

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

In Transit: Use SSL/TLS to encrypt data while it’s being transferred. At Rest: Enable server-side encryption (SSE) for services like S3, or use AWS Key Management Service (KMS) for managing encryption keys.

5. How does AWS ensure data durability in S3?

AWS S3 provides 99.999999999% durability by automatically replicating data across multiple geographically separated facilities within a region.

6. What are the key components of Amazon Kinesis?

Key components of Amazon Kinesis:

Kinesis Data Streams: Real-time data streaming.
Kinesis Data Firehose: Load streaming data into data lakes and analytics services.
Kinesis Data Analytics: Analyze streaming data using SQL.
Kinesis Video Streams: Stream video data for analytics and machine learning.

7. How does AWS handle high availability?

AWS ensures high availability using:

Availability Zones (AZs) spread across Regions.
Services like Elastic Load Balancing (ELB) and Auto Scaling.
Multi-AZ deployments for databases like RDS.

8. What are Security Groups in AWS?

In AWS, Security Groups act as virtual firewalls for the EC2 instances that control inbound and outbound traffic.

Granular Access Control:
They allow you to permit access to the resources by specifying IP ranges, protocols, and port numbers.
Enhance Security:
Security Groups block all inbound traffic and permit all outbound traffic.
Stateless Filtering:
They track traffic flows and automatically allow responses to inbound requests.

9. How is CloudWatch different from CloudTrail?

CloudWatch monitors resource performance and operational data like CPU usage, memory, disk usage. It tracks operational health of applications and services and sets alarms for performance thresholds. CloudTrail logs API calls and user activity for auditing. It tracks resource changes for compliance and governance. Cloud trail helps in security analysis and forensic investigations.

10. What is AWS IAM and its key components?

AWS Identity and Access Management (IAM) enables secure access control with:

Users: Individual identities with permissions to access AWS resources.
Groups: Collections of users to manage permissions collectively.
Roles: Assignable permissions for services or users, including cross-account access.
Policies: JSON documents that define permissions and access rules.

User and Access Management:

Create and manage users, groups, and roles for controlled access to AWS resources.

Granular Permissions:

Define policies to grant or restrict specific permissions for users or roles.

Secure Cross-Account Access:

Enable trusted access between different AWS accounts using roles.

Multi-Factor Authentication (MFA):

Add an extra layer of security for user logins.

Temporary Security Credentials:

Use roles to provide temporary access to AWS resources for applications and services.

11. How does Route 53 provide DNS services?

Route 53 routes end users to applications by translating human-readable domain names into IP addresses using features like:

Geolocation routing
Latency-based routing
Weighted routing

Route 53 is used to perform domain registration, DNS management, and routing.

Domain Registration:

DNS Management:

Host and manage the Domain Name System (DNS) for routing internet traffic to AWS services or external resources.

Traffic Routing:

Supports various routing policies such as:

Simple Routing: Standard DNS resolution.
Latency-Based Routing: Routes users to the lowest-latency region.
Geolocation Routing: Directs traffic based on the user’s geographic location.
Weighted Routing: Distributes traffic based on assigned weights to different resources.
Failover Routing: Automatically redirects traffic during resource failures.

12. What are the types of EC2 instance types available?

Types of EC2 instance types:

General Purpose (e.g., t2, m5)
Compute Optimized (e.g., c5)
Memory Optimized (e.g., r5)
Storage Optimized (e.g., i3)
GPU Instances (e.g., p3)

Amazon EC2 is used to perform web and application hosting, big data processing, development, testing, high-performance computing and batch Processing.

13. Explain EBS Volume types in AWS.

EBS volumes provide persistent block storage for EC2 instances, ensuring data availability even when instances stop or restart. They support scalability, backup, and encryption for diverse application needs.

Types of EBS Volumes:

General Purpose SSD (gp3, gp2): Balanced performance for a wide range of workloads, including boot volumes and small databases.
Provisioned IOPS SSD (io1, io2): High-performance volumes for mission-critical, low-latency applications like large databases.
Throughput Optimized HDD (st1): Low-cost storage for high-throughput, sequential workloads like data warehouses.
Cold HDD (sc1): Cheapest option for infrequently accessed data such as archives.
Magnetic (standard, legacy): Low-cost option primarily for backward compatibility and legacy workloads.
General Purpose SSD (gp3, gp2): Balanced performance for a wide range of workloads, including boot volumes and small databases.
Provisioned IOPS SSD (io1, io2): High-performance volumes for mission-critical, low-latency applications like large databases.
Throughput Optimized HDD (st1): Low-cost storage for high-throughput, sequential workloads like data warehouses.
Cold HDD (sc1): Cheapest option for infrequently accessed data such as archives.
Magnetic (standard, legacy): Low-cost option primarily for backward compatibility and legacy workloads.

14. How do you secure sensitive information in environment variables for Lambda functions?

AWS Secrets Manager and AWS Systems Manager Parameter can be used to securely manage sensitive information. AWS Secrets Manager enhances security by securely storing, managing, and retrieving sensitive information such as database credentials, API keys, and other secrets.

The Key parameters in AWS Secrets Manager are
Secret Name: Unique identifier
Secret Value: Sensitive data
Description: Optional metadata
Tags: Labels for organization and resource tracking.
KMS Key: Encryption key
Rotation Configuration: Settings for automated secret rotation.
Access Policies: IAM permissions for managing access.
Version Stages: Track secret versions

15. How does AWS Auto Scaling work?

AWS Auto Scaling automatically adjusts the number of compute resources like EC2 instances, based on demand. It adjusts capacity to maintain optimal performance and cost by scaling EC2 instances based on predefined rules.

16. What is the use of Elastic Beanstalk?

AWS Elastic Beanstalk is a fully managed service that simplifies deploying, managing, and scaling web applications and services. It allows developers to focus on code and supports

Multiple programming languages and platforms,
Handling infrastructure provisioning,
Load balancing, scaling, and monitoring.

17. Explain about Amazon RDS?

Amazon Relational Database Service (RDS) simplifies database management and supports engines like MySQL, PostgreSQL, and Aurora.

Database Management: Automates setup, patching, backups, and scaling.
Multi-AZ Deployment: Ensures high availability and disaster recovery.
Read Replicas: Improves read performance.
Security: Supports encryption and access control.
Cost Efficiency: Pay-as-you-go pricing model.
Scalability: Easily scale

18. How do you manage cross-account access in AWS?

To manage and grant cross-account access, use IAM roles with trust relationships and assume-role permissions.

IAM Roles grant temporary permissions to entities like AWS services, applications and users for secure access to resources. They support:

Cross-account access,
Least privilege access,
Service-to-service interactions.

19. How kubernetes clusters are managed?

Amazon Elastic Kubernetes Service (EKS) manages Kubernetes clusters for deploying containerized applications.

Amazon EKS (Elastic Kubernetes Service) is used for:

Managed Kubernetes: Automates Kubernetes deployment and management.
Scalability: Easily scale containerized applications.
High Availability: Ensures uptime with multi-AZ support.
Security: Integrates with AWS services like IAM and VPC.
Hybrid Deployments: Supports on-premise and cloud environments.
Efficient Operations: Reduces operational overhead by managing Kubernetes control planes.

20. Explain VPC Flow Logs.

VPC Flow Logs capture information about IP traffic flowing to and from network interfaces in your VPC. VPC Flow Logs are used for:

Traffic Monitoring: Capture network traffic in VPC.
Security Analysis: Detect unauthorized access or threats.
Troubleshooting: Diagnose network connectivity and latency issues.
Compliance Auditing: Maintain logs for regulatory requirements.
Performance Insights:

21. How does AWS Glue work?

AWS Glue is a fully managed ETL service that prepares data for analytics by automatically generating ETL scripts. It simplifies extracting, transforming, and loading (ETL) data for analytics. AWS Glue helps to discover, prepare, and combine data from multiple sources for storage in data lakes and data warehouses. It automates schema discovery, code generation, and job scheduling for efficient data processing.

22. Explain about the uses of Amazon SNS

Amazon Simple Notification Service (SNS) enables message delivery to subscribing endpoints like email, SMS, and Lambda.

Amazon SNS is used for:

Message Delivery: Sending notifications to users via SMS, email, or mobile push.
Application Alerts: Real-time system alerts and monitoring.
Decoupling Microservices: Facilitating communication between decoupled applications or components.
Scalable Messaging: Sending messages to millions of subscribers.
Event-Driven Architecture: Triggering actions based on specific events.

23. What are AWS WAF and Shield?

AWS WAF:

Web Application Firewall to protect web applications from threats. Protecting web applications from common web exploits like SQL injection and cross-site scripting (XSS). It helps filter and monitor HTTP requests to safeguard against malicious traffic.

AWS Shield:

DDoS protection service with Standard and Advanced tiers. Protecting against Distributed Denial of Service (DDoS) attacks. AWS Shield Standard automatically protects all AWS customers, while AWS Shield Advanced offers enhanced protection and detailed attack diagnostics for more critical applications.

24. How does AWS Direct Connect work?

AWS Direct Connect is a dedicated network connection between an on-premises data center and AWS. It provides a more secure, reliable, and consistent network experience compared to using the internet. AWS Direct Connect reduces network costs, increases bandwidth throughput, and improves latency by bypassing the public internet for data transfer.

25. What is S3 Lifecycle Management?

Automatically manages object storage by transitioning data between different storage classes and expiring objects after a set time.

26.What are the types of AWS Elastic Load Balancers?

AWS Elastic Load Balancer (ELB) is a service that automatically distributes incoming traffic across multiple targets. It ensures high availability, fault tolerance, and optimal performance for applications. ELB supports different types like Application, Network, Gateway, and Classic to handle various use cases and traffic patterns.

Types of AWS ELB

Application Load Balancer (ALB)
Network Load Balancer (NLB)
Gateway Load Balancer (GLB)
Classic Load Balancer (CLB)

27. What is the function of AWS CodePipeline?

AWS CodePipeline is a fully managed CI/CD (Continuous Integration and Continuous Delivery) service that automates the build, test, and deployment process for application updates. It enables fast and reliable delivery of features and updates by orchestrating workflows across various tools and services CodePipeline automates continuous integration and delivery of applications.

28. How does AWS Storage Gateway work?
AWS Storage Gateway is a hybrid cloud storage service that connects on-premises environments to AWS. It allows seamless integration of on-premises applications with cloud storage, enabling data backup, archiving, disaster recovery, and cloud data processing. It offers three types of gateways:

File Gateway: For file-based storage using NFS/SMB, storing files as S3 objects.

Volume Gateway: For block storage, presenting cloud-backed iSCSI volumes.

Tape Gateway: For virtual tape libraries (VTL) for backup workflows.

AWS Storage Gateway provides hybrid cloud storage by integrating on-premises environments with AWS cloud storage. It helps reduce storage costs while maintaining local performance.

29. What are AWS Outposts?

AWS Outposts extends AWS infrastructure to your on-premises data centers for consistent hybrid operations. It extends AWS infrastructure, services, and tools to on-premises environments which enable hybrid cloud solutions. Key uses include:

Hybrid Applications: Running latency-sensitive and local data-processing applications near the source while integrating with AWS services.
Data Residency: Meeting regulatory or compliance requirements by keeping data on-premises.
Edge Computing: Supporting workloads that require local processing, such as IoT, machine learning, and video analytics

30. What are Reserved Instances?

Reserved Instances provide discounts for long-term usage (1 or 3 years) of EC2 instances.

Reserved Instances (RIs) in AWS are a cost-saving option for predictable workloads. They provide discounts in exchange for committing to use a specific instance type for a 1- or 3-year term. Key uses include:

Cost Optimization: Achieve significant savings (up to 75%) compared to On-Demand pricing for long-term workloads.
Predictable Workloads: Ideal for steady-state applications like databases, web servers, and enterprise applications.
Budget Planning: Fixed-term pricing helps in forecasting and controlling cloud spending.

31. What is the difference between AWS Aurora and RDS?

Feature	Aurora	RDS
Compatibility	MySQL/PostgreSQL-compatible	Supports multiple database engines (MySQL, PostgreSQL, SQL Server, Oracle, MariaDB)
Performance	High performance designed for cloud scalability	Managed service with standard performance
Use Case	For mission-critical, high throughput applications	For general managed relational database needs

32. How does AWS Lambda handle concurrency?

The concurrency is handled by AWS Lambda using creation of separate instances of a function to handle multiple requests simultaneously. The number of concurrent executions is limited by the account’s concurrency limit, which can be configured using Reserved Concurrency settings.

33. What is Amazon MQ and Elastic File System (EFS)?

Amazon MQ manages message brokers using open-source APIs like Apache ActiveMQ. EFS provides scalable, elastic, and shared file storage for use with AWS services.

34. How would you migrate a large on-premises database to AWS with minimal downtime?

Use AWS Database Migration Service (DMS) for live data replication to AWS.
Create a replica of the source database on AWS using DMS while keeping the on-premises database active.
Use AWS Schema Conversion Tool (SCT) to handle schema changes if migrating to a different database engine.
Perform a cutover to the AWS database during a maintenance window.
Ensure proper testing and rollback plans before migration.

35. What are Spot Fleets and tags in AWS?

Spot Fleets enable you to launch a group of Spot Instances to meet specified capacity and resource requirements. Tags are metadata labels (key-value pairs) attached to AWS resources for cost tracking and organization.

36. How would you secure the bucket to store sensitive data in S3?

To enforce fine-grained access control and to grant least-privileged access, enable Bucket Policies and use IAM roles and policies. Enable S3 encryption and MFA Delete using AWS-managed keys or customer-managed keys and to prevent accidental or unauthorized deletions. Use S3 Object Lock for WORM (Write Once Read Many) compliance and enable CloudTrail to log bucket access and activity.

37. What are Amazon Athena, AWS Data Pipeline and AWS Transit Gateway?

Athena is a serverless query service for analyzing data in S3 using SQL.

AWS Data Pipeline is a service to process and move data between AWS services and on-premises storage AWS Transit Gateway is a service that connects VPCs and on-premises networks using a central hub for easier network management.

38. How would you design a disaster recovery solution for a business-critical application hosted on AWS?

Use a Multi-AZ deployment for databases like Amazon RDS for high availability.
Implement a backup and restore strategy with automated snapshots using AWS Backup.
Use Cross-Region Replication for S3 buckets to ensure data redundancy.
Set up a pilot light architecture for minimal resources in the DR region, scaling them up during failover.

39. What steps would you take to optimize costs if the AWS bills are rising?

To analyze spending patterns, Use AWS Cost Explorer and AWS Budgets and Identify and terminate unused or underutilized resources.

Leverage Savings Plans or Reserved Instances for predictable workloads. Use Spot Instances for fault-tolerant workloads.

Enable S3 Intelligent-Tiering for optimized storage costs. Optimize databases using Aurora Serverless or RDS instance sizing.

40. How do you optimize S3 performance?

Use multipart uploads for large files.
Enable S3 Transfer Acceleration for faster data transfers.
Partition data based on access patterns.

41. What are the types of databases supported by AWS?

Relational Databases (RDS)
NoSQL Databases (DynamoDB)
Data Warehousing (Redshift)
In-memory Databases (ElastiCache)

42. How would you design a serverless application using AWS services?

Use AWS Lambda to run the application’s business logic without provisioning servers.
Deploy an API Gateway to expose RESTful APIs or WebSocket endpoints for client communication.
Use DynamoDB or Amazon Aurora Serverless for a highly scalable, managed database.
Store static content like HTML, CSS, or JS in S3 and use CloudFront for low-latency content delivery.

43. What is CloudFront and Shared Responsibility Model?

CloudFront is a content delivery network (CDN) that caches content globally to reduce latency for end users. AWS is responsible for the security of the cloud, while customers are responsible for security in the cloud.

44. How would you design an application for high availability on AWS?

Distribute the application across multiple Availability Zones for fault tolerance. Use an Application Load Balancer to route traffic across healthy EC2 instances or containers. Deploy the database in Multi-AZ mode, such as Amazon RDS or DynamoDB global tables. Enable auto-scaling for EC2 instances to handle traffic surges. Store application backups in S3 with lifecycle policies for redundancy. Use Route 53 for DNS failover to ensure availability during regional outages.

45. What is an AMI in AWS?

Amazon Machine Image (AMI) is a pre-configured template used to launch EC2 instances.

Key uses of AMI

Instance Launch: AMIs provide the operating system, software, and configurations required to launch EC2 instances.
Custom Images: Create custom AMIs with pre-installed applications and settings for faster deployments.
Scalability: Use AMIs to launch multiple instances with identical configurations in Auto Scaling Groups.
Backup: Use AMIs to create snapshots of running instances for disaster recovery or replication.

46. How would you implement a CI/CD pipeline in AWS?

To store source code repositories, use CodeCommit and Configure CodeBuild for building and testing the application.

Use CodeDeploy to automate application deployment to EC2, Lambda, or ECS. Use CodePipeline to orchestrate the CI/CD process, including build, test, and deploy stages. Integrate with third-party tools like Jenkins or GitHub Actions if required. Implement rollback strategies and test automation for reliable deployments..

47. What is AWS Key Management Service (KMS)?

KMS manages encryption keys for secure data storage and access.

Key uses of KMS

Data Encryption: KMS is used to encrypt data stored in services like S3, EBS, RDS, and Redshift using customer-managed keys (CMKs).
Access Control: It provides fine-grained access control over who can use or manage encryption keys, using IAM policies.
Key Rotation: Automatically rotate encryption keys to meet security and compliance requirements. Compliance: Helps meet regulatory requirements by enabling encryption at rest and managing cryptographic operations with audit logs via CloudTrail.

48. How would you design a solution for processing large datasets in AWS?

To catalog, prepare, and transform data, use AWS Glue and Store raw data in S3 and use S3 Lifecycle Policies for cost optimization.

Use Amazon EMR for processing large datasets with frameworks like Spark or Hadoop. For real-time processing, use Kinesis Data Streams with Lambda or Kinesis Analytics. Store processed data in Redshift for analytics or DynamoDB for transactional queries. Visualize data using Amazon QuickSight or export it to a data lake.

49. How to improve frontend performance in AWS applications?

Implement pagination or use AWS AppSync to fetch data in manageable pages.
Utilize virtualization libraries to efficiently render only visible list items.
Optimize React components with memoization and lazy loading to reduce unnecessary re-renders.

50. What are AWS best practices for authentication and authorization?

Best Practice	Description
Authentication	Use AWS Cognito for secure user authentication and JWT token management.
Access Control	Apply fine-grained IAM policies tailored to user roles.
API Security	Protect APIs with API Gateway authorizers or Lambda authorizers for request validation.

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AWS Interview Questions Experienced