[Nebius]: Add fabrics list to provider_data (#192)

Associate each Nebius catalog item with a list of
InfiniBand fabrics that it supports. The list of
fabrics and their details is hardcoded until
Nebius exposes it in the API.

Previously, the list of fabrics was hardcoded in
dstack. Moving it to gpuhunt allows to add new
fabrics without a dstack release.

Author: jvstme

src/gpuhunt/providers/nebius.py

@@ -1,6 +1,7 @@
 import logging
 import re
-from typing import Optional
+from dataclasses import dataclass
+from typing import Optional, cast
 
 from nebius.aio.channel import Credentials
 from nebius.api.nebius.billing.v1alpha1 import (
@@ -26,11 +27,13 @@
     TenantServiceClient,
 )
 from nebius.sdk import SDK
+from typing_extensions import TypedDict
 
 from gpuhunt._internal.constraints import find_accelerators
 from gpuhunt._internal.models import (
     AcceleratorInfo,
     AcceleratorVendor,
+    JSONObject,
     QueryFilter,
     RawCatalogItem,
 )
@@ -40,6 +43,26 @@
 TIMEOUT = 7
 
 
+@dataclass(frozen=True)
+class InfinibandFabric:
+    name: str
+    platform: str
+    region: str
+
+
+# https://docs.nebius.com/compute/clusters/gpu#fabrics
+INFINIBAND_FABRICS = [
+    InfinibandFabric("fabric-2", "gpu-h100-sxm", "eu-north1"),
+    InfinibandFabric("fabric-3", "gpu-h100-sxm", "eu-north1"),
+    InfinibandFabric("fabric-4", "gpu-h100-sxm", "eu-north1"),
+    InfinibandFabric("fabric-5", "gpu-h200-sxm", "eu-west1"),
+    InfinibandFabric("fabric-6", "gpu-h100-sxm", "eu-north1"),
+    InfinibandFabric("fabric-7", "gpu-h200-sxm", "eu-north1"),
+    InfinibandFabric("us-central1-a", "gpu-h200-sxm", "us-central1"),
+    InfinibandFabric("us-central1-b", "gpu-b200-sxm", "us-central1"),
+]
+
+
 class NebiusProvider(AbstractProvider):
     NAME = "nebius"
 
@@ -77,6 +100,10 @@ def get(
         return items
 
 
+class NebiusCatalogItemProviderData(TypedDict):
+    fabrics: list[str]
+
+
 def get_sample_projects(sdk: SDK) -> dict[str, str]:
     """
     Returns:
@@ -141,6 +168,12 @@ def make_item(
     spot: bool,
     price: float,
 ) -> Optional[RawCatalogItem]:
+    fabrics = []
+    if preset.allow_gpu_clustering:
+        fabrics = [
+            f.name for f in INFINIBAND_FABRICS if f.platform == platform and f.region == region
+        ]
+
     item = RawCatalogItem(
         instance_name=f"{platform} {preset.name}",
         location=region,
@@ -153,6 +186,7 @@ def make_item(
         gpu_vendor=None,
         spot=spot,
         disk_size=None,
+        provider_data=cast(JSONObject, NebiusCatalogItemProviderData(fabrics=fabrics)),
     )
 
     if preset.resources.gpu_count:

src/integrity_tests/test_nebius.py

@@ -1,4 +1,5 @@
 import csv
+import json
 from operator import itemgetter
 from pathlib import Path
 
@@ -28,3 +29,41 @@ def test_spots_presented(data_rows: list[dict]):
 @pytest.mark.parametrize("location", ["eu-north1", "eu-west1"])
 def test_location_present(location: str, data_rows: list[dict]):
     assert location in map(itemgetter("location"), data_rows)
+
+
+def test_fabrics_unique(data_rows: list[dict]) -> None:
+    for row in data_rows:
+        fabrics = json.loads(row["provider_data"])["fabrics"]
+        assert len(fabrics) == len(set(fabrics)), f"Duplicate fabrics in row: {row}"
+
+
+def test_fabrics_on_sample_offer(data_rows: list[dict]) -> None:
+    for row in data_rows:
+        if (
+            row["instance_name"] == "gpu-h100-sxm 8gpu-128vcpu-1600gb"
+            and row["location"] == "eu-north1"
+        ):
+            break
+    else:
+        raise ValueError("Offer not found")
+    fabrics = set(json.loads(row["provider_data"])["fabrics"])
+    expected_fabrics = {
+        "fabric-2",
+        "fabric-3",
+        "fabric-4",
+        "fabric-6",
+    }
+    missing_fabrics = expected_fabrics - fabrics
+    assert not missing_fabrics
+
+
+def test_no_fabrics_on_sample_non_clustered_offer(data_rows: list[dict]) -> None:
+    for row in data_rows:
+        if (
+            row["instance_name"] == "gpu-h100-sxm 1gpu-16vcpu-200gb"
+            and row["location"] == "eu-north1"
+        ):
+            break
+    else:
+        raise ValueError("Offer not found")
+    assert json.loads(row["provider_data"])["fabrics"] == []