AWS
Core cloud services, networking, IAM, storage, compute, and scaling.
What is the difference between an EC2 instance and a Lambda function?
EC2 is a virtual server you manage, while Lambda is serverless execution managed by AWS.
What is the difference between S3 and EBS?
S3 is object storage, while EBS is block storage attached to EC2.
What is the difference between an IAM role and an IAM policy?
A role is an identity that can be assumed, while a policy defines permissions.
What is the difference between a public subnet and a private subnet?
A public subnet has a route to the internet gateway, while a private subnet does not.
What is the difference between an Application Load Balancer and a Network Load Balancer?
ALB works at Layer 7 for HTTP/HTTPS, while NLB works at Layer 4 for TCP/UDP.
What is Auto Scaling in AWS?
Auto Scaling automatically adjusts the number of resources based on demand or policies.
What is the difference between a Security Group and a Network ACL?
Security Groups are stateful instance-level firewalls, while Network ACLs are stateless subnet-level filters.
What is Route 53 used for?
Route 53 is AWS DNS service used for domain management, routing, and health checks.
What is the difference between running a database on RDS and on EC2?
RDS is managed database service, while EC2 gives full control but also full operational responsibility.
What components make up a VPC?
A VPC includes subnets, route tables, internet gateways, NAT gateways, and security controls.
What is a NAT Gateway used for?
A NAT Gateway allows instances in private subnets to access the internet without being publicly exposed.
What is the difference between EBS and instance store?
EBS is persistent storage, while instance store is temporary and tied to the instance lifecycle.
What types of scaling exist in AWS?
Scaling can be vertical or horizontal, and in AWS typically horizontal via Auto Scaling.
What is AWS CloudFront?
CloudFront is a CDN that caches content closer to users to reduce latency.
What is AWS?
AWS is a cloud platform providing on-demand infrastructure and services.
What is the difference between a Region and an Availability Zone?
A Region is a geographic area, and Availability Zones are isolated data centers within a Region.
What is a VPC?
A VPC is a virtual network where you run AWS resources.
What is a subnet?
A subnet is a segment of a VPC where resources are placed.
What is an Internet Gateway?
It allows communication between a VPC and the internet.
What is an Elastic IP?
An Elastic IP is a static public IP address in AWS.
What is a Security Group?
A Security Group is a stateful firewall for EC2 instances.
What is a Network ACL?
A Network ACL is a stateless firewall at the subnet level.
What is IAM?
IAM manages users, roles, and permissions in AWS.
What is an IAM policy?
An IAM policy defines permissions in JSON format.
What is CloudWatch?
CloudWatch is a monitoring and logging service.
What is CloudTrail?
CloudTrail logs API calls and account activity.
What is AWS Lambda?
Lambda runs code without managing servers.
What is API Gateway?
API Gateway is used to create and manage APIs.
What is SQS?
SQS is a message queue service.
What is SNS?
SNS is a pub/sub messaging service.
What is the difference between SQS and SNS?
SQS is queue-based, SNS is pub/sub.
What is RDS?
RDS is a managed relational database service.
What is DynamoDB?
DynamoDB is a NoSQL database service.
What is ELB?
ELB distributes incoming traffic across multiple targets.
What is ALB?
ALB is a Layer 7 load balancer for HTTP/HTTPS.
What is NLB?
NLB is a Layer 4 load balancer for TCP/UDP.
What is an Auto Scaling Group?
It automatically adjusts EC2 instances based on demand.
What is a Launch Template?
It defines how EC2 instances should be launched.
What is CloudFormation?
CloudFormation is Infrastructure as Code for AWS.
What is EBS?
EBS is block storage for EC2 instances.
Why use CloudFront?
CloudFront reduces latency by caching content globally.
What routing policies does Route 53 support?
It supports simple, weighted, latency, failover, and geolocation routing.
What are IAM best practices?
Use least privilege, roles instead of keys, and enable MFA.
How do you optimize AWS costs?
Use reserved instances, auto scaling, and monitoring.