runner-up cuts CI costs with fresh per-job runners

runner-up targets the expensive, operationally messy middle ground between persistent self-hosted runners and Kubernetes-heavy autoscaling.

• –Fresh environments reduce cross-job contamination and cleanup problems.
• –Supports Docker, KVM, macOS virtualization, Hyper-V, and host execution across mixed hardware.
• –GitHub scale sets, SSH-based agents, resource-aware scheduling, and configurable job ordering make spare machines usable as one runner fleet.
• –Refusing fork-based jobs by default is a sensible security baseline for private repositories.
• –The tradeoff is significant operational ownership: teams still manage hardware, images, SSH access, updates, and failure recovery.