Compute
Amazon EC2
Virtual servers with full control
Amazon EC2 provides resizable virtual machines with complete OS control. Pricing models include On-Demand, Savings Plans, Reserved Instances, Spot (up to ~90% off, interruptible), and Dedicated Hosts (for licensing/compliance). Placement groups and instance types tune performance.
When to use it
- Workloads needing OS-level control, specific kernels, or licensing
- Steady-state high-utilization services
- Apps requiring persistent instance-level state
- GPU or specialized hardware
When NOT to use it
- Short event-driven tasks (use Lambda)
- Apps that don't need OS access (consider containers or serverless)
Key exam points
- On-Demand = flexibility; Savings Plans/Reserved = discounts for commitment; Spot = interruptible discounts
- Auto Scaling groups maintain capacity and scale across AZs
- Placement groups: cluster (low latency), spread (isolation), partition (large distributed)
- Instance store is ephemeral; EBS persists
Compared with
- AWS Lambda — Lambda removes server management for short tasks; EC2 gives full control for long-running or specialized workloads.