--- title: "AWS Beginner Flashcards" description: "Core AWS concepts across Compute, Storage, Networking, Databases, IAM, Serverless, Monitoring, and High Availability for beginners using spaced repetition." author: "Mohammad Abu Mattar" canonical: https://mkabumattar.com/flashcards/post/aws-beginner-flashcards --- # AWS Beginner Flashcards ## Flashcards ### 1. What is Amazon EC2? Amazon EC2 (Elastic Compute Cloud) is a web service that provides resizable virtual servers (instances) in the cloud. You can launch, stop, and terminate instances on demand, paying only for what you use. ### 2. What is an EC2 instance type? An instance type defines the CPU, memory, storage, and networking capacity of an EC2 instance. Types are grouped into families such as General Purpose (t3, m6), Compute Optimized (c6), and Memory Optimized (r6). ### 3. What is an AMI? An AMI (Amazon Machine Image) is a pre-configured template used to launch EC2 instances. It includes the OS, application server, and any additional software. You can use AWS-provided AMIs or create your own. ### 4. What is AWS Lambda? AWS Lambda is a serverless compute service that runs your code in response to events without provisioning or managing servers. You are billed only for the compute time your code actually consumes, in milliseconds. ### 5. What is Amazon ECS? Amazon ECS (Elastic Container Service) is a fully managed container orchestration service that lets you run, stop, and manage Docker containers on a cluster of EC2 instances or using AWS Fargate (serverless). ### 6. What is the difference between EC2 and Lambda? EC2 provides persistent virtual machines you manage (OS, runtime, scaling). Lambda is event-driven and serverless you only provide the function code, and AWS handles everything else. Lambda suits short-lived tasks; EC2 suits long-running workloads. ### 7. What is Amazon S3? Amazon S3 (Simple Storage Service) is an object storage service offering industry-leading scalability, availability, and durability. Objects are stored in buckets and can be accessed via HTTP(S). It is commonly used for backups, static websites, and data lakes. ### 8. What is an S3 bucket? An S3 bucket is a container for storing objects (files and their metadata) in Amazon S3. Bucket names must be globally unique. Access is controlled via bucket policies and IAM. ### 9. What is Amazon EBS? Amazon EBS (Elastic Block Store) provides persistent block storage volumes for use with EC2 instances. Unlike instance storage, EBS volumes persist independently of the instance lifecycle and can be attached and detached. ### 10. What is the difference between S3 and EBS? S3 is object storage accessed over the internet, ideal for unstructured data, backups, and static files. EBS is block storage attached directly to an EC2 instance like a hard drive, suited for databases and OS volumes. ### 11. What is Amazon EFS? Amazon EFS (Elastic File System) is a scalable, fully managed NFS file system that can be mounted simultaneously by multiple EC2 instances. It grows and shrinks automatically as you add and remove files. ### 12. What is a VPC? A VPC (Virtual Private Cloud) is a logically isolated section of the AWS cloud where you can launch resources in a virtual network that you define. You control IP ranges, subnets, route tables, and gateways. ### 13. What is the difference between a public and private subnet? A public subnet has a route to an Internet Gateway, allowing resources in it to communicate with the internet. A private subnet has no direct internet route resources there access the internet only through a NAT Gateway or NAT instance. ### 14. What is an Internet Gateway? An Internet Gateway (IGW) is a horizontally scaled, redundant VPC component that allows communication between your VPC and the internet. It enables resources in public subnets to send and receive internet traffic. ### 15. What is Amazon Route 53? Amazon Route 53 is a scalable DNS (Domain Name System) web service. It translates human-readable domain names into IP addresses and supports routing policies like simple, weighted, latency-based, and failover. ### 16. What is Amazon CloudFront? Amazon CloudFront is a fast content delivery network (CDN) service. It caches content at global edge locations close to users, reducing latency for websites, APIs, and media streams. ### 17. What is a Security Group? A Security Group acts as a virtual firewall for EC2 instances, controlling inbound and outbound traffic at the instance level using allow rules. Security Groups are stateful return traffic is automatically allowed. ### 18. What is a NAT Gateway? A NAT Gateway allows instances in a private subnet to initiate outbound internet traffic (e.g., for software updates) while preventing the internet from initiating connections to those instances. ### 19. What is Amazon RDS? Amazon RDS (Relational Database Service) is a managed service that makes it easy to set up, operate, and scale relational databases in the cloud. It supports MySQL, PostgreSQL, MariaDB, Oracle, and SQL Server. ### 20. What is Amazon DynamoDB? Amazon DynamoDB is a fully managed, serverless NoSQL key-value and document database. It delivers single-digit millisecond performance at any scale and automatically handles replication and scaling. ### 21. What is the difference between RDS and DynamoDB? RDS is a managed relational (SQL) database suited for structured data with complex queries and joins. DynamoDB is a NoSQL database suited for high-speed, large-scale workloads with simple key-based access patterns. ### 22. What is Amazon ElastiCache? Amazon ElastiCache is a fully managed in-memory caching service compatible with Redis and Memcached. It speeds up applications by storing frequently accessed data in memory, reducing load on databases. ### 23. What is AWS IAM? AWS IAM (Identity and Access Management) lets you manage access to AWS services and resources securely. You create users, groups, and roles, then attach policies that define what actions are allowed or denied. ### 24. What is an IAM Policy? An IAM Policy is a JSON document that defines permissions. It specifies which AWS actions are allowed or denied on which resources, and can be attached to users, groups, or roles. ### 25. What is the principle of least privilege? The principle of least privilege means granting only the minimum permissions needed to perform a task. It reduces the attack surface by ensuring users and services cannot access resources beyond what their job requires. ### 26. What is an IAM Role? An IAM Role is an identity with permission policies that can be assumed by AWS services, applications, or users from other accounts. Unlike users, roles do not have long-term credentials they issue temporary security tokens. ### 27. What is the AWS root account? The root account is the account created when you first sign up for AWS. It has unrestricted access to all resources. AWS strongly recommends not using the root account for daily tasks and instead creating IAM users with limited permissions. ### 28. What is MFA in AWS? MFA (Multi-Factor Authentication) adds an extra layer of security by requiring a second form of verification (such as a code from an authenticator app) in addition to a password. AWS recommends enabling MFA on the root account and all privileged IAM users. ### 29. What is Amazon API Gateway? Amazon API Gateway is a fully managed service for creating, publishing, and securing REST, HTTP, and WebSocket APIs at any scale. It is commonly used as the front door for Lambda-based serverless applications. ### 30. What is Amazon SQS? Amazon SQS (Simple Queue Service) is a fully managed message queuing service that decouples components of distributed systems. Producers send messages to a queue; consumers poll and process them independently. ### 31. What is Amazon SNS? Amazon SNS (Simple Notification Service) is a fully managed pub/sub messaging service. A publisher sends a message to a topic, and SNS fans it out to all subscribed endpoints such as Lambda, SQS, email, or HTTP. ### 32. What is the difference between SQS and SNS? SQS is a pull-based queue where one consumer processes each message. SNS is a push-based pub/sub system that broadcasts messages to multiple subscribers simultaneously. They are often combined SNS fans out to multiple SQS queues. ### 33. What is Amazon CloudWatch? Amazon CloudWatch is a monitoring and observability service for AWS resources. It collects metrics, logs, and events, and allows you to set alarms, create dashboards, and trigger automated actions based on thresholds. ### 34. What is a CloudWatch Alarm? A CloudWatch Alarm watches a single metric over a time period and performs one or more actions when the metric crosses a defined threshold. Actions can include sending an SNS notification or triggering an Auto Scaling policy. ### 35. What is AWS CloudTrail? AWS CloudTrail records API calls and user activity across your AWS account. It provides an audit trail of who did what, when, and from where essential for security analysis, compliance, and troubleshooting. ### 36. What is AWS CodePipeline? AWS CodePipeline is a fully managed CI/CD service that automates the build, test, and deploy phases of your release process. It integrates with CodeBuild, CodeDeploy, GitHub, and other tools. ### 37. What is AWS CodeBuild? AWS CodeBuild is a fully managed continuous integration service that compiles source code, runs tests, and produces deployment-ready artifacts. You pay only for the build minutes consumed. ### 38. What is an Availability Zone (AZ)? An Availability Zone is one or more discrete data centers with redundant power, networking, and connectivity within an AWS Region. Distributing resources across multiple AZs protects applications from data center failures. ### 39. What is an AWS Region? An AWS Region is a physical geographic area containing multiple, isolated Availability Zones. Each Region is completely independent, allowing you to deploy globally and meet data residency requirements. ### 40. What is Auto Scaling? AWS Auto Scaling automatically adjusts the number of EC2 instances (or other resources) in response to demand. It can scale out (add instances) during traffic spikes and scale in (remove instances) when demand drops, optimizing cost and availability. ### 41. What is an Elastic Load Balancer (ELB)? An Elastic Load Balancer automatically distributes incoming traffic across multiple targets (EC2 instances, containers, IPs) in one or more Availability Zones. It improves fault tolerance and prevents any single instance from being overwhelmed. ### 42. What is the difference between vertical and horizontal scaling? Vertical scaling (scale up) means increasing the size of an existing instance (more CPU, RAM). Horizontal scaling (scale out) means adding more instances to distribute load. AWS favors horizontal scaling for better availability and cost efficiency. ### 43. What is an RDS Multi-AZ deployment? In a Multi-AZ deployment, RDS automatically provisions and maintains a synchronous standby replica in a different Availability Zone. If the primary instance fails, RDS automatically fails over to the standby with minimal downtime.