hearth is what I built to schedule every job on my homelab's GPU

Every scheduled job in my homelab runs through a platform I built called hearth, and one piece of it is a gateway that admits one job at a time to whichever machine happens to be running a model. It runs on the Pi, and it exists because nothing else that could do the job fit the hardware. Kubernetes-style orchestration (k3s, Nomad) carries its own memory tax, and the Pi was already sitting at 5 GiB used plus 4.4 GiB of swap before adding a scheduler to the pile. Plain systemd timers per service were the other option, and they don't do priority ordering, backpressure, or a shared budget across jobs, which is most of what a GPU with one model slot needs.

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