InfiniBand and RoCE Labels

CoreWeave automatically applies a set of topology and performance labels to Nodes that are connected to high-performance backend fabrics such as InfiniBand and RoCE (RDMA over Converged Ethernet). You can use these labels to:

control where Pods are scheduled, and
monitor the health and capacity of the backend network.

Backend labels use a common, fabric-agnostic schema and are applied to both InfiniBand and RoCE Nodes. InfiniBand Nodes also expose an additional set of InfiniBand-specific labels that remain available for existing workloads and dashboards.

Label	Description
`backend.coreweave.cloud/flavor`	The type of backend high-performance fabric attached to the Node, for example `infiniband` or `roce`.
`backend.coreweave.cloud/fabric`	The name of the backend fabric, representing a distinct InfiniBand or RoCE fabric.
`backend.coreweave.cloud/leafgroup-name`	A human-readable identifier for the group of leaf switches (leafgroup or Pod) that serve a common set of Nodes.
`backend.coreweave.cloud/leafgroup`	An identifier for the same leafgroup or Pod. This is convenient in dashboards or alerts where a compact identifier is preferred over `leafgroup-name`.
`backend.coreweave.cloud/neighbors.expected.{interface}.device`	The ID of the expected leaf connected to the Node at this physical interface
`backend.coreweave.cloud/neighbors.expected.{interface}.port-id`	The ID of the expected port connected to the Node at this physical interface.
`backend.coreweave.cloud/neighbors.expected.{interface}.port-name`	The expected port name on the leaf or Pod switch (if exported by the fabric), which can make dashboards and runbooks easier to interpret than raw port numbers alone.
`backend.coreweave.cloud/neighbors.current.{interface}.device`	The ID of the current leaf connected to the Node at this physical interface.
`backend.coreweave.cloud/neighbors.current.{interface}.port-id`	The ID of the current port connected to the Node at this physical interface.
`backend.coreweave.cloud/neighbors.current.{interface}.port-name`	The name of the current port on the leaf, when exposed by the fabric.
`backend.coreweave.cloud/speed.current`	The current speed of the backend network connected to the Node.
`backend.coreweave.cloud/speed.expected`	The expected speed of the backend network for optimal performance.
`backend.coreweave.cloud/superpod`	The number identifying the superpod within the backend topology.
`node.coreweave.cloud/rack`	The number identifying the physical rack where the Node is located.

InfiniBand compatible labels

InfiniBand Nodes also expose ib.coreweave.cloud/* labels. These labels carry the same topology and speed information, but use an InfiniBand-specific prefix that predates the backend schema and may still appear in existing workloads and dashboards. The table below shows how the InfiniBand labels relate to the backend schema:

InfiniBand label(s)	Backend-equivalent label(s)	Description
`ib.coreweave.cloud/fabric`	`backend.coreweave.cloud/fabric`	InfiniBand fabric name representing a distinct InfiniBand fabric within a Region.
`ib.coreweave.cloud/leafgroup`, `ib.coreweave.cloud/leafgroup-name`	`backend.coreweave.cloud/leafgroup`, `backend.coreweave.cloud/leafgroup-name`	Numeric and human-readable identifiers for the leafgroup or Pod that serves a common set of Nodes.
`ib.coreweave.cloud/neighbors.`, `ib.coreweave.cloud/ports.`	`backend.coreweave.cloud/neighbors.*`	Per-interface and aggregate neighbor / port information on InfiniBand Nodes. The backend per-interface labels are the modern, fabric-agnostic schema.
`ib.coreweave.cloud/speed.current`, `ib.coreweave.cloud/speed.expected`	`backend.coreweave.cloud/speed.current`, `backend.coreweave.cloud/speed.expected`	Current and expected speed of the InfiniBand network connected to the Node
`ib.coreweave.cloud/superpod`	`backend.coreweave.cloud/superpod`	The number identifying the superpod within the InfiniBand topology.

For new deployments and dashboards, we recommend building on the backend.coreweave.cloud/* labels wherever possible, while continuing to recognize the ib.coreweave.cloud/* labels on existing InfiniBand clusters.

Using labels for Pod affinity

You can use these labels in Pod affinity and anti-affinity rules to steer workloads toward specific parts of the fabric. Common use cases include:

keeping large multi-Node jobs within a single rack or superpod,
choosing between InfiniBand and RoCE fabrics, and
separating different workloads across fabrics and racks for fault-isolation or performance reasons.

Example: Target a specific backend fabric, superpod, and rack

The following Pod affinity rule targets Nodes on a specific backend fabric and superpod, restricted to a given rack. It also ensures that Pods land on either RoCE-backed or InfiniBand-backed Nodes by setting backend.coreweave.cloud/flavor appropriately:

affinity:
  nodeAffinity:
    requiredDuringSchedulingIgnoredDuringExecution:
      nodeSelectorTerms:
      - matchExpressions:
        - key: backend.coreweave.cloud/flavor
          operator: In
          values:
          - roce # Or 'infiniband' for InfiniBand-backed Nodes
        - key: backend.coreweave.cloud/fabric
          operator: In
          values:
          - [FABRIC-NAME] # Your backend fabric name
        - key: backend.coreweave.cloud/superpod
          operator: In
          values:
          - [SUPERPOD-NUMBER] # Your superpod number
        - key: node.coreweave.cloud/rack
          operator: In
          values:
          - [RACK-NUMBER] # Your rack number

On older InfiniBand-only clusters that do not yet expose the backend labels, you can instead match directly on:

ib.coreweave.cloud/fabric
ib.coreweave.cloud/superpod
node.coreweave.cloud/rack

using the same affinity pattern.

Networking

Documentation Index

​InfiniBand compatible labels

​Using labels for Pod affinity

​Example: Target a specific backend fabric, superpod, and rack

InfiniBand compatible labels

Using labels for Pod affinity

Example: Target a specific backend fabric, superpod, and rack