AWS Core Services

Overview of AWS Core Services — The foundational building blocks for cloud infrastructure.

What Are AWS Core Services?

AWS Core Services are the fundamental building blocks of the AWS Cloud. Every AWS application, from simple websites to complex AI systems, is built on these services.

Key Insight: Learn core services first. They form the base for advanced AWS services, including databases and AI/ML.

The Core Services Landscape

flowchart TB
    subgraph AWS["AWS Core Services"]
        direction TB
        subgraph Foundation["Foundation Layer"]
            IAM["🔐 IAM<br/>Identity & Access"]
            VPC["🌐 VPC<br/>Networking"]
            S3["📦 S3<br/>Storage"]
        end
        subgraph Compute["Compute Layer"]
            EC2["🖥️ EC2<br/>Compute"]
            Lambda["⚡ Lambda<br/>Serverless"]
        end
    end
    
    EC2 --> IAM
    EC2 --> VPC
    EC2 --> S3
    Lambda --> IAM
    Lambda --> VPC
    Lambda --> S3

Core Services Overview

IAM — Identity and Access Management

What it does: Controls who can access what in your AWS account.

Concept	Description
Users	Individual identities for people or applications (federation/roles preferred where possible)
Groups	Collections of users with shared permissions
Policies	JSON documents defining permissions
Roles	Temporary credentials for services and cross-account access

Why it matters: IAM is the foundation of AWS security. Every AWS service uses IAM for access control.

Learn more: IAM Overview

S3 — Simple Storage Service

What it does: Object storage with unlimited scalability and 11 nines durability.

Storage Class	Use Case
S3 Standard	Frequently accessed data
S3 Intelligent-Tiering	Unknown access patterns
S3 Standard-IA	Infrequently accessed data
Glacier Instant Retrieval	Rarely accessed, need immediate access
Glacier Deep Archive	Long-term archival (12+ months)

Why it matters: S3 is the most widely used AWS service — the backbone of data storage for everything from websites to AI data lakes.

Learn more: Amazon S3

VPC — Virtual Private Cloud

What it does: Your isolated network in the AWS Cloud.

Component	Purpose
Subnets	Segments of your VPC (public or private)
Security Groups	Stateful firewall (instance-level)
NACLs	Stateless firewall (subnet-level)
Internet Gateway	Enables internet access for public subnets
NAT Gateway	Enables outbound internet for private subnets

Why it matters: VPC provides the network isolation and security that every AWS resource runs within.

Learn more: Amazon VPC

EC2 — Elastic Compute Cloud

What it does: Virtual servers in the AWS cloud.

Pricing Model	Savings	Use Case
On-Demand	None	Short-term, spiky workloads
Reserved	Up to 75%	Steady-state, predictable usage
Spot	Up to 90%	Fault-tolerant, flexible workloads
Savings Plans	Up to 72%	Flexible compute commitment

Why it matters: EC2 is the IaaS foundation of AWS — giving you full control over virtual machines.

Learn more: Amazon EC2

Lambda — Serverless Compute

What it does: Run code without managing servers.

Feature	Value
Pricing	Per request ($0.20/million) + compute time
Free Tier	1M requests + 400K GB-seconds/month
Timeout	Max 15 minutes
Triggers	API Gateway, S3, SNS, DynamoDB Streams, EventBridge

Why it matters: Lambda enables event-driven architectures and automatic scaling without managing infrastructure.

Learn more: AWS Lambda

How Core Services Work Together

Example: Web Application Architecture

flowchart TD
    Internet["🌐 Internet"]
    IGW["Internet Gateway<br/><i>VPC Component</i>"]
    ALB["Application Load Balancer"]
    Web["🖥️ EC2 Web Servers"]
    App["🖥️ EC2 App Servers"]
    RDS["🗄️ RDS Database"]
    S3["📦 S3 Assets"]
    CW["📊 CloudWatch"]
    
    Internet --> IGW
    IGW --> ALB
    ALB --> Web
    ALB --> App
    Web --> App
    App --> RDS
    RDS --> S3
    RDS --> CW

All access controlled by IAM Policies

Learning Path

Beginner

Start with IAM — Understand how AWS access control works
Learn S3 — Store your first objects
Explore VPC — Understand network isolation

Intermediate

Master EC2 — Launch and manage virtual machines
Learn Lambda — Build serverless applications

Advanced

Integrate services — Build architectures combining all core services

TL;DR

Core Services = Foundational AWS services
IAM = Identity and access control (who can do what)
S3 = Object storage (unlimited, 11 nines durability)
VPC = Your isolated network (security + connectivity)
EC2 = Virtual servers (IaaS)
Lambda = Serverless compute (event-driven)
All work together = Every AWS application uses these services

Quick Links

Service	Description
IAM Overview	Users, Groups, Policies, Roles
Amazon S3	Object storage + storage classes
Amazon VPC	Networking + security
Amazon EC2	Virtual machines + pricing models
AWS Lambda	Serverless compute + event triggers

Lalit's Cloud & DevOps notes