Amazon EC2 Cheat Sheet Hub

Amazon EC2 (Elastic Compute Cloud) is the original AWS service and still one of the highest-tested topics across SAA-C03, SAP-C02, DVA-C02, and DOP-C02. While serverless and container workloads have grown significantly, EC2 remains the foundation for stateful applications, high-performance computing, GPU workloads, and any scenario requiring OS-level control.

The EC2 service cheat sheet covers the full picture: instance families (General Purpose T/M, Compute C, Memory R/X, Storage I/D, Accelerated P/G/Inf), purchasing options (On-Demand, Spot, Reserved, Dedicated Hosts, Savings Plans), placement groups (Cluster, Spread, Partition), the Nitro hypervisor, instance metadata and user data, and the EC2 lifecycle (running, stopped, terminated). Key exam facts: stopped instances still accrue EBS charges, Spot instances can be interrupted with a 2-minute warning, and Dedicated Hosts are required for BYOL licensing compliance.

EC2 storage is its own domain — the EBS cheat sheet covers volume types (gp3, gp2, io2, io1, st1, sc1), IOPS and throughput limits, encryption, snapshots, and Multi-Attach for io1/io2. The EBS gp2 vs gp3 vs io1 vs io2 comparison sheet is the key reference for storage performance decisions on EC2.

Compute architecture decisions often involve choosing between EC2, Lambda, ECS, EKS, and Fargate. The Lambda vs ECS vs EKS vs Fargate comparison and the Elastic Beanstalk vs ECS vs App Runner comparison sheets cover the full decision space. For load balancing, the ALB vs NLB vs CLB vs Gateway LB comparison resolves which load balancer type fits which workload.

Auto Scaling is central to EC2 high availability — target tracking vs step scaling vs scheduled scaling policies, scale-in protection, and the relationship between ASGs, launch templates, and Elastic Load Balancing appear on almost every SAA-C03 scenario question involving availability and cost optimization.