AWS Core Services Master Cheatsheet: EC2, S3, RDS, Lambda & VPC

Introduction: AWS Core Services Foundation

Amazon Web Services offers hundreds of cloud services, but five form the backbone of most cloud architectures: EC2 for compute, S3 for storage, RDS for managed databases, Lambda for serverless functions, and VPC for networking. Mastering these services provides the foundation for building scalable, reliable, and cost-effective cloud applications.

EC2 (Elastic Compute Cloud): Virtual Servers in the Cloud

EC2 Key Concepts

EC2 Instance Types

EC2 Pricing Models

EC2 Command Reference

# Launch a new instance
aws ec2 run-instances --image-id ami-12345678 --instance-type t2.micro --key-name MyKeyPair

# Describe instances
aws ec2 describe-instances

# Stop an instance
aws ec2 stop-instances --instance-ids i-1234567890abcdef0

# Start an instance
aws ec2 start-instances --instance-ids i-1234567890abcdef0

# Terminate an instance
aws ec2 terminate-instances --instance-ids i-1234567890abcdef0

EC2 Best Practices

• Use the latest generation of instance types for better price/performance
• Implement auto-scaling groups to handle variable workloads
• Use EC2 User Data for bootstrap configuration
• Apply proper tags for resource management and cost allocation
• Use instance profiles instead of storing credentials
• Regularly back up EBS volumes with snapshots
• Implement proper security groups and NACLs

S3 (Simple Storage Service): Scalable Object Storage

S3 Key Concepts

S3 Storage Classes

S3 Command Reference

# Create a bucket
aws s3 mb s3://mybucket

# List buckets
aws s3 ls

# Upload file to bucket
aws s3 cp myfile.txt s3://mybucket/

# Download file from bucket
aws s3 cp s3://mybucket/myfile.txt .

# Sync local directory with bucket
aws s3 sync myfolder s3://mybucket/myfolder

# List objects in bucket
aws s3 ls s3://mybucket

# Delete object from bucket
aws s3 rm s3://mybucket/myfile.txt

# Delete bucket
aws s3 rb s3://mybucket --force

S3 Best Practices

• Use bucket policies and IAM policies for access control
• Enable versioning for critical data
• Implement lifecycle rules to move data between storage classes
• Use S3 Transfer Acceleration for large file uploads
• Enable server-side encryption for sensitive data
• Use S3 Event Notifications to trigger workflows
• Implement S3 Access Points for complex permissions
• Use S3 Object Lock for WORM (Write Once Read Many) compliance

RDS (Relational Database Service): Managed Relational Databases

RDS Key Concepts

RDS Database Engines

RDS Instance Types

RDS Command Reference

# Create DB instance
aws rds create-db-instance --db-instance-identifier mydb --db-instance-class db.t3.micro \
  --engine mysql --master-username admin --master-user-password password \
  --allocated-storage 20

# Describe DB instances
aws rds describe-db-instances

# Create DB snapshot
aws rds create-db-snapshot --db-instance-identifier mydb --db-snapshot-identifier mydb-snapshot

# Restore from snapshot
aws rds restore-db-instance-from-db-snapshot --db-instance-identifier mynewdb \
  --db-snapshot-identifier mydb-snapshot

# Delete DB instance
aws rds delete-db-instance --db-instance-identifier mydb --skip-final-snapshot

RDS Best Practices

• Use Multi-AZ deployments for high availability
• Deploy read replicas for read scaling and reporting
• Implement automated backups with appropriate retention
• Use parameter groups to optimize database configuration
• Monitor performance with Enhanced Monitoring and Performance Insights
• Create maintenance windows during low-traffic periods
• Use IAM authentication for database access
• Right-size instances based on workload characteristics

Lambda: Serverless Computing

Lambda Key Concepts

Lambda Limits & Quotas

Lambda Supported Runtimes

Lambda Command Reference

# Create function
aws lambda create-function --function-name my-function \
  --zip-file fileb://my-function.zip --handler index.handler \
  --runtime nodejs20.x --role arn:aws:iam::123456789012:role/lambda-role

# Invoke function
aws lambda invoke --function-name my-function \
  --payload '{"key":"value"}' response.json

# Update function code
aws lambda update-function-code --function-name my-function \
  --zip-file fileb://my-function-updated.zip

# Configure function
aws lambda update-function-configuration --function-name my-function \
  --timeout 30 --memory-size 256

# Delete function
aws lambda delete-function --function-name my-function

Lambda Best Practices

• Keep functions focused on a single task
• Initialize SDK clients and database connections outside handler
• Use environment variables for configuration
• Implement proper error handling and logging
• Set appropriate memory allocation for performance
• Use Provisioned Concurrency for latency-sensitive applications
• Leverage Lambda Layers for code reuse
• Implement dead-letter queues for failed event processing
• Use AWS X-Ray for tracing and debugging

VPC (Virtual Private Cloud): Isolated Network Infrastructure

VPC Key Concepts

VPC Subnet Types

VPC CIDR Blocks & IP Addressing

Note: AWS reserves the first 4 IP addresses and the last IP address in each subnet CIDR block.

VPC Command Reference

# Create VPC
aws ec2 create-vpc --cidr-block 10.0.0.0/16

# Create subnet
aws ec2 create-subnet --vpc-id vpc-1234567890abcdef0 \
  --cidr-block 10.0.1.0/24 --availability-zone us-west-2a

# Create internet gateway
aws ec2 create-internet-gateway

# Attach internet gateway to VPC
aws ec2 attach-internet-gateway --internet-gateway-id igw-1234567890abcdef0 \
  --vpc-id vpc-1234567890abcdef0

# Create route table
aws ec2 create-route-table --vpc-id vpc-1234567890abcdef0

# Create route to internet
aws ec2 create-route --route-table-id rtb-1234567890abcdef0 \
  --destination-cidr-block 0.0.0.0/0 --gateway-id igw-1234567890abcdef0

# Associate route table with subnet
aws ec2 associate-route-table --route-table-id rtb-1234567890abcdef0 \
  --subnet-id subnet-1234567890abcdef0

VPC Best Practices

• Design VPC CIDR for future growth
• Create subnets across multiple Availability Zones
• Use private subnets for all non-public-facing resources
• Implement security groups and NACLs in layers
• Use VPC endpoints for private access to AWS services
• Enable VPC Flow Logs for network monitoring
• Use Transit Gateway for complex networking
• Implement proper IP address management
• Use Network Firewall for advanced security

Cross-Service Integration Patterns

Storage Integration

Compute Integration

Database Integration

Networking Integration

Common Design Patterns & Architectures

Three-Tier Web Application

1. Web Tier (Public Subnet)

   • EC2 instances behind load balancer
   • Auto Scaling Group for scalability
   • Security Group allowing HTTP/HTTPS

2. Application Tier (Private Subnet)

   • EC2 instances with application code
   • Auto Scaling Group for scalability
   • Security Group allowing specific ports from web tier

3. Database Tier (Private Subnet)

   • RDS instance with Multi-AZ
   • Security Group allowing only application tier access

Serverless Web Application

1. Front-end

   • S3 for static website hosting
   • CloudFront for content delivery

2. API Layer

   • API Gateway for request management
   • Lambda functions for business logic
   • IAM roles for access control

3. Data Layer

   • DynamoDB for NoSQL data storage
   • S3 for object storage
   • RDS (Aurora Serverless) for relational data

Hybrid Architecture

1. On-premises Connection

   • Direct Connect or Site-to-Site VPN
   • Transit Gateway for network routing

2. AWS Resources

   • VPC with private subnets
   • EC2 instances for compute
   • S3 for storage

3. Data Synchronization

   • Database replication
   • S3 Transfer Acceleration

AWS Exam & Certification Tips

EC2 Focus Areas

• Instance types and families
• Instance purchasing options
• AMI selection and management
• Storage options (EBS vs Instance Store)
• Security groups vs NACLs
• Placement groups

S3 Focus Areas

• Storage classes and transitions
• Bucket policies and ACLs
• Encryption options
• Static website hosting
• Versioning and lifecycle policies
• Cross-region replication

RDS Focus Areas

• Database engine features
• Multi-AZ vs Read Replicas
• Backup and restore options
• Security and encryption
• Parameter and option groups
• Monitoring and metrics

Lambda Focus Areas

• Event sources and triggers
• Function configuration
• Cold start behavior
• Concurrency management
• Security and permissions
• Monitoring and troubleshooting

VPC Focus Areas

• CIDR blocks and subnetting
• Routing and internet access
• Security groups vs NACLs
• VPC endpoints and PrivateLink
• VPC peering and Transit Gateway
• NAT gateway vs NAT instance

Resources for Further Learning

Official AWS Documentation

• Amazon EC2 Documentation
• Amazon S3 Documentation
• Amazon RDS Documentation
• AWS Lambda Documentation
• Amazon VPC Documentation

AWS Whitepapers

• AWS Well-Architected Framework
• AWS Security Best Practices
• AWS Storage Services Overview
• Serverless Applications Lens

AWS Training and Certification

• AWS Certified Solutions Architect – Associate
• AWS Certified Developer – Associate
• AWS Certified SysOps Administrator – Associate
• AWS Skill Builder