☁️ AWS & Infrastructure

Services, networking, architecture patterns

Compute

EC2

Virtual servers. Instance types: t3 (burst), m5 (general), c5 (compute), r5 (memory)

Key: AMI, Security Groups, EBS
Lambda

Serverless functions. 15 min max, 10GB RAM. Pay per invocation+duration

Key: Cold start, layers, triggers
ECS / Fargate

Container orchestration. ECS = EC2-backed, Fargate = serverless containers

Key: Task definitions, services
EKS

Managed Kubernetes. Control plane managed by AWS

Key: Pods, nodes, Helm

Storage

S3

Object storage. 11 9's durability. Tiers: Standard, IA, Glacier, Deep Archive

Key: Bucket policies, versioning, lifecycle
EBS

Block storage for EC2. gp3 (SSD), io2 (high IOPS), st1 (throughput HDD)

Key: Snapshots, encryption
EFS

Managed NFS. Shared across AZs. Auto-scaling

Key: Mount targets, throughput modes
ElastiCache

Managed Redis/Memcached. Sub-ms latency

Key: Cluster mode, replication

Database

RDS

Managed SQL: PostgreSQL, MySQL, MariaDB, Oracle, SQL Server

Key: Multi-AZ, read replicas, backups
Aurora

Cloud-native SQL. 5× MySQL / 3× PostgreSQL performance. Auto-scales

Key: Serverless v2, Global Database
DynamoDB

Serverless NoSQL. Single-digit ms latency. Key-value + document

Key: Partition key, GSI, DAX cache

Networking

VPC

Virtual network. Subnets (public/private), route tables, NACLs

Key: CIDR, NAT Gateway, VPC Peering
ALB / NLB

ALB: HTTP/HTTPS (L7). NLB: TCP/UDP (L4). Target groups

Key: Path-based routing, health checks
CloudFront

CDN. Edge locations worldwide. Cache static + dynamic content

Key: Origins, behaviors, invalidation
Route 53

DNS. Routing policies: simple, weighted, latency, failover, geolocation

Key: Alias records, health checks

Integration

SQS

Message queue. Standard (at-least-once) / FIFO (exactly-once). 14 day retention

Key: Visibility timeout, DLQ, long polling
SNS

Pub/sub notifications. Fan-out to SQS, Lambda, HTTP, email

Key: Topics, subscriptions, filtering
EventBridge

Serverless event bus. Schema registry. 300+ AWS sources

Key: Rules, targets, content filtering
Step Functions

Workflow orchestration. State machines. Visual designer

Key: Standard/Express, error handling

DevOps / CI/CD

CloudFormation

Infrastructure as Code. JSON/YAML templates. Stacks, change sets

Key: Drift detection, nested stacks
CodePipeline

CI/CD pipeline. Source → Build → Deploy stages

Key: Actions, artifacts, approvals
CloudWatch

Monitoring + logging. Metrics, alarms, dashboards, log groups

Key: Custom metrics, log insights
IAM

Identity & access. Users, roles, policies. Principle of least privilege

Key: Trust policies, STS, MFA

Common Architecture Patterns

3-Tier Web App
CloudFront ALB EC2/ECS RDS + ElastiCache
Serverless API
API Gateway Lambda DynamoDB + S3
Event-Driven
EventBridge SQS Lambda DynamoDB
Microservices
ALB ECS Fargate (per service) RDS/DynamoDB + SQS
Data Pipeline
Kinesis Lambda / Glue S3 Athena / Redshift

Cost Optimization

1 Reserved Instances / Savings Plans for steady workloads
2 Spot Instances for batch/fault-tolerant jobs (up to 90% off)
3 S3 Lifecycle policies: move to IA → Glacier → Deep Archive
4 Lambda: right-size memory (CPU scales with memory)
5 CloudWatch: set billing alarms + budget alerts
6 Use VPC endpoints to avoid NAT Gateway data transfer costs