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Module 2 — Compute in the Cloud

Status: ✅ done · Domain 3 · Full notes in the Study hub → Domain 3 Compute.

Key points

• Amazon EC2 — resizable virtual servers. Default tenancy = shared/multi-tenant (isolated by the Nitro hypervisor). Single-tenant options: Dedicated Instances, Dedicated Hosts (BYOL).
• Instance families: general purpose · compute optimized · memory optimized · storage optimized · accelerated (GPU).
• EC2 pricing (heavily tested): On-Demand (default, spiky) · Reserved Instances (1–3 yr commit, steady) · Savings Plans (commit $/hr, flexible) · Spot (~90% off, interruptible) · Dedicated Hosts (licensing).
• EC2 Auto Scaling = elasticity (add/remove instances to match demand).
• Elastic Load Balancing (ELB) = spreads traffic → high availability; pairs with Auto Scaling.
• Messaging: SQS = queue, pull-based, decouple components · SNS = pub/sub topic, push-based, fan-out.

Exam: Spot = cheapest but interruptible · RI / Savings Plans = commit for discount · SQS = queue (pull), SNS = pub/sub (push).