CloudScale-Sim

You'd reach for this when you need to simulate auto-scaling behavior in cloud infrastructure without spinning up actual resources. It lets you model load patterns and test how your scaling policies respond before deploying to production. The source is minimal, so I can't speak to specific providers or metrics it supports, but the premise is solid: inject synthetic load scenarios, watch virtual instances scale up and down, and validate your thresholds. Useful for catching configuration mistakes or understanding cost implications of aggressive scaling policies when you're still in the planning phase or don't want to rack up cloud bills testing in live environments.