> ## Documentation Index
> Fetch the complete documentation index at: https://docs.nebius.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Working with InfiniBand™ topology of a GPU cluster

[InfiniBand topology](/compute/clusters/gpu/topology) can help you increase performance of multi-VM jobs in GPU clusters.

## How to get InfiniBand topology of a GPU cluster

After you [create a GPU cluster and add VMs to it](/compute/clusters/gpu#how-to-enable-infiniband-for-vms-with-gpus), you can view the InfiniBand topology of this cluster and its VMs.

<Tabs>
  <Tab title="Cluster topology">
    To get the topology for all VMs in a GPU cluster, run the following command:

    ```bash theme={null}
    nebius compute gpu-cluster get --id computegpucluster-***
    ```

    In the `--id` parameter, specify the GPU cluster ID.

    The output example is the following:

    ```text theme={null}
    ...
    status:
      infiniband_topology_path:
        instances:
          - instance_id: computeinstance-***rnqz
            path:
              - ***27bf
              - ***bb9b
              - ***b7ad
          - instance_id: computeinstance-***pepp
            path:
              - ***27bf
              - ***bb9b
              - ***e1ff
          - ...
    ```
  </Tab>

  <Tab title="VM topology">
    To get the topology for an individual VM, run the following command:

    ```bash theme={null}
    nebius compute instance get --id computeinstance-***
    ```

    In the `--id` parameter, specify the ID of the VM attached to the GPU cluster.

    The output example is the following:

    ```text theme={null}
    ...
    status:
      infiniband_topology_path:
        path:
          - ***27bf
          - ***bb9b
          - ***e1ff
    ```
  </Tab>
</Tabs>

The `path` parameter shows components of the [InfiniBand network layers](/compute/clusters/gpu/topology#architecture-of-infiniband-topology):

```text theme={null}
path:
  - ***27bf # 1st network layer (InfiniBand fabric)
  - ***bb9b # 2nd network layer (point of delivery, POD)
  - ***e1ff # 3rd network layer (scalable unit, SU)
```

## How to create the Slurm topology configuration

To set up topology in [Slurm](https://slurm.schedmd.com) and run jobs for ML workloads, you need the [topology.conf](https://slurm.schedmd.com/topology.conf.html) file. This file shows the network hierarchy: how nodes are interconnected, what layers they are located at and what switches are used.

The `topology.conf` file represents InfiniBand topology. You can create this file based on the [information about a given GPU cluster](#how-to-get-infiniband-topology-of-a-gpu-cluster). To create the file, run one of the scripts from the [Nebius AI Cloud solution library](https://github.com/nebius/nebius-solution-library/tree/main/scripts/ib-topology) on GitHub.

***

*InfiniBand and InfiniBand Trade Association are registered trademarks of the InfiniBand Trade Association.*