tenancy

A replica per variant is 100 copies of a 140 GB base and 800 GPUs mostly idle; multi-LoRA holds the base once and hundreds of adapters in a few gigabytes. The memory arithmetic, the throughput cost of mixed batches, the routing that keeps hot adapters resident, and the two cases where a variant earns its own replica.

A request can cost 50 tokens or 50,000, so a request limit protects nothing. The two buckets per tenant per model, the reservation-then-settle scheme for output tokens you cannot count in advance, the distributed counter fast enough for the gateway, and how the limits map onto the fleet's real capacity.

A GPU cloud sells whole nodes and fabric slices to tenants who expect them in minutes and expect them to work. The node state machine, the reconciler that keeps thousands converging, the isolation lines on shared fabric, the health loop that pulls a bad node first, and billing that survives a control-plane outage.