---
title: "Tdx Preflight"
method: POST
path: "/servers/tdx/preflight"
tags: ["Servers"]
---

# Tdx Preflight

`POST /servers/tdx/preflight`

Can this exact image boot on this host? The one call a launch/upgrade preflight makes.

A check against both a host profile and the measurement set, so it hangs off neither. The API
fingerprints the submitted profile and answers whether a published measurement for the caller's
`(version, rc)` carries that fingerprint -- the whole launch decision in one boolean:

  * `launchable: true`  -> the VM will attest; launch.
  * `launchable: false` -> register the class (POST /servers/tdx/host_profiles), then retry once
    Chutes publishes its measurement.

Stores nothing and reveals nothing beyond the answer -- not the full measurement set, not
whether a profile row exists. Signed by the miner hotkey, so the signature covers the body.

## Query parameters

- `version` string, required — VM image version the caller intends to boot.
- `rc` boolean — Whether that image is a release-candidate (debug) build.

## Headers

- `X-Chutes-Hotkey` string, nullable
- `X-Chutes-Signature` string, nullable
- `X-Chutes-Nonce` string, nullable
- `Authorization` string, nullable

## Request body

- HostProfile — The document sek8s ``discover-profile.sh`` emits for one machine -- the whole submitted body, and what gets stored. Every key the script emits is modeled and every block forbids extras, so compatibility is one-way: an older script still validates (defaults fill in), but a script that adds a key 422s until the API models it. Add the field here, deploy, then roll out the script.
  - `hostname` string, nullable
  - `timestamp` string, nullable
  - `host` HostProfilePlatform — DMI/SMBIOS identity (board, BIOS, chassis) plus OS release. Recorded, not fingerprinted -- BIOS revisions move independently of the host class.
    - `product_name` string
    - `board_vendor` string
    - `board_name` string
    - `bios_vendor` string
    - `bios_version` string
    - `bios_date` string
    - `os_version_id` string
  - `launch_determinism` HostProfileQemu, required — QEMU build and the ``-cpu`` string it launches with -- both RTMR0 determinants. Wire key is ``launch_determinism``. Its last three members restate ``numa`` and ``cpu``; they are declared so real submissions validate, but nothing reads them (``fingerprint`` takes those values from their canonical block, so a disagreeing copy cannot shift it).
    - `qemu_version` string, required
    - `qemu_version_full` string
    - `cpu_args` string
    - `numa_node_count` integer
    - `numa_topology_eligible` boolean
    - `host_cpu_topology` string
  - `gpu` HostProfileGpu, required — Passthrough GPU inventory: PCI ids and addresses, count, BAR/VRAM sizing, VBIOS.
    - `pci_device_ids` string[]
    - `bdfs` string[]
    - `count` integer, required
    - `vram_gb` number, nullable
    - `bar_size_mb` integer
    - `numa_nodes` integer[]
    - `vbios` string[]
  - `pci_topology` string, nullable
  - `cpu` HostProfileCpu, required — Host CPU topology and the identity fields RTMR0 depends on.
    - `total` integer, required
    - `sockets` integer, required
    - `cores_per_socket` integer, required
    - `threads_per_core` integer, required
    - `cpu_vendor` string
    - `cpu_processor_id` string, nullable
  - `memory` HostProfileMemory, required — Host RAM, which some profiles (e.g. B200) derive guest RAM from. The ``suggested_*`` fields are the script's own sizing advice, recorded but unused.
    - `total_gb` number, required
    - `suggested_ram_per_gpu_gb` integer
    - `suggested_total_vm_ram_gb` integer
  - `numa` HostProfileNuma, required — NUMA layout: node count, node indices, per-node cpulists.
    - `node_count` integer, required
    - `nodes` integer[]
    - `cpus_per_node` object
  - `nic` HostProfileNic — InfiniBand / Ethernet inventory, including passthrough-eligible NICs.
    - `ib_class_count` integer
    - `eth_class_count` integer
    - `ib_devices` string[]
    - `bridge_pfs` string[]
    - `passthrough_candidates` string[]
    - `passthrough_numa_nodes` integer[]
  - `nvswitch` HostProfileNvswitch — NVSwitch inventory (passthrough stubs are reproduced offline per switch).
    - `present` boolean
    - `count` integer
    - `devices` string[]
    - `numa_nodes` integer[]

## Response `200`

Successful Response

- PreflightResponse — Response for POST /servers/tdx/preflight: can this exact image boot on this host? A check against both a host profile and the measurement set, so it hangs off neither -- it fingerprints the submitted profile and asks whether a measurement for the requested image covers it.
  - `fingerprint` string, required
  - `launchable` boolean, required
  - `detail` string, required

## Other responses

- `422` — Validation Error

---

[API](https://skmtc.dev/chutes/apis/fastapi.md) · [All operations](https://skmtc.dev/chutes/apis/fastapi/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/chutes/fastapi/revisions/7be1aa2fe1a0/schema)