# Placement and scheduling profiles

> How Nodus chooses where a run executes, what the estimate includes, and how profiles, deadlines and budgets change the choice.

Source: https://www.nodus-compute.ai/docs/concepts/supply-placement/
Build revision: 4ebfc6023eeed1bd55d9969af1612182a7b0c7ff

By default Nodus places each run on the **cheapest offering that can start it now**: the lowest hourly rate among the offerings that fit your request, have a machine free and stay within your limits. If that offering cannot be used, the next cheapest takes the run. Review the estimate before launch.

## Profiles

`placement.profile` picks how the scheduler trades cost against time:

|Profile|Chooses|
|-|-|
|`Balanced` (default)|The lowest hourly rate that meets your deadline and budget. Among offerings within 2 % of that rate, the healthier one, or the one that starts sooner, fits better or is already warm|
|`Cost`|The lowest expected cost to completion, startup, teardown and lost work included, even if it is slower to start. Among offerings within 2 % of that cost, warm capacity and a better fit win|
|`Speed`|The fastest expected finish among offerings within 1.5 × the cheapest expected cost|

`Balanced` never chooses an offering whose rate is more than 2 % above the cheapest that meets your limits, and `Cost` never chooses one whose expected cost is more than 2 % above the cheapest at equal health; `interruptible: Prefer` gives interruptible capacity a 10 % allowance. Under `Cost` and `Speed`, an offering that often fails to start counts as dearer by that risk; under every profile, one that recently failed to start ranks lower for a few minutes within the 2 % band. When two offerings are within 2 % of each other, identical requests are spread across both instead of all taking the same one.

## Deadlines and budgets

* `placement.completeByTime`: offerings whose p90 finish is later are not used.
* `maxCostUSD`, Budgets and your balance: offerings whose expected cost exceeds the money left are not used.
* `placement.maxRateUSDPerHour`: offerings above this rate are not used.

If nothing remains, the run waits in `Queued` and the estimate says why, for example `MissesDeadline` or `ExceedsRemainingBudget`.

## Estimates and the If-Match ceiling

`--dry-run=server -o estimate` returns the expected cost p50 and p90, the startup time (cold, and warm when idle capacity of yours fits), the first hold, the minimum charge and `validUntil`, which is at most 31 minutes away. Creating with the estimate’s `If-Match` binds the launch to it: Nodus then uses no offering above the estimated rate plus 10 %, unless you set `placement.maxRateUSDPerHour` yourself. If prices moved beyond that, the run waits with `PriceAboveEstimate` instead of costing more than you saw.

## Reuse before new capacity

Before acquiring capacity, the scheduler considers idle capacity that fits your request. CPU work can share Nodus nodes. A [BYOC pool](https://www.nodus-compute.ai/docs/guides/pools/) named in `placement.pool` is considered first.

## Why a placement was made

`nodus describe` shows each attempt’s placement: the profile, the scores of the chosen offering (fit, time to result, cost to complete, recovery value, health), the fallbacks in order and every rejected offering with its reason. Offerings are shown by name, such as `h100-sxm-80g-x8-us`.

## Multi-node runs (Beta)

For `spec.distributed`, Nodus first resolves the topology (nodes × GPUs per node) and then places every node together:

* `network: Colocated` (the default) keeps every node in one location on one network; `Regional` keeps them in one region class; `Global` allows anywhere.
* `transport: Direct` uses only private or direct paths between nodes; `Auto` also allows the relayed mesh, with lower bandwidth.
* Review the estimate for the whole gang before launch.

If no set of offerings satisfies these rules, the run waits with `GangInfeasible`. See [multi-node training](https://www.nodus-compute.ai/docs/guides/multi-node/).