Planning considerations for cluster networks

Contact your IBM Support representative if you are interested in getting early access to this offering. It is currently available for early access users of the gx3d-160x1792x8h100 virtual server instance profiles in the us-east region.

Review the following planning considerations before creating a cluster network.

• Ensure that you have a sufficient compute quota to support the resources you will deploy in to your cluster network. Typically, these instances require a quota increase prior to provisioning.

  Currently, NVIDIA H100 is the only instance profile that you can select. For more information about this profile, see x86-64 instance profiles.

• Instance profiles have a recommended number of cluster subnets. To identify IBM Cloud's recommendation for cluster subnets for a given instance type:

  Recommended number of cluster subnets for instance profiles.

  Instance Profile Type	Recommended Cluster Subnets to Cluster vNICs
  gx3d-160x1792x8h100	1:1

  • gx3d-160x1792x8h100 supports either 8, 16 or 32 cluster vNICs. As a result, you should have a corresponding number of cluster subnets.
  • If you are unsure about the correct number of cluster vNICs for your workload, IBM Cloud recommends using 8 for the gx3d-160x1792x8h100 profile.

  Ensure that the IP address ranges used for your cluster network subnets do not overlap with those of your cloud subnets. Overlapping ranges can lead to networking issues.

• Start by setting up your cluster network and subnets, then define instance templates to scale your training cluster with the desired number of nodes. For more information, see Getting started with cluster networks.

  • You can create an instance template to define instance details for provisioning one or more virtual servers. When you create your instance template, you can use it to provision single virtual server instances, or to provision multiple instances at the same time as part of an instance group.
  • Optionally, when you provision an instance, you can include the cluster network configuration within the instance provision request.

• Considerations for statically-configured IP addresses:

  • If you need to plan for statically-configured IP addresses, especially for a large number (such as 1000), it’s important to approach the task methodically. First, you should determine the total number of required IP addresses. Then consider how these addresses will be assigned to various instances. To manage this efficiently, implement a clear naming scheme that helps you organize and connect the IP addresses to their respective instances. For example, you might use a naming convention that reflects the function or location of each instance, making it easier to identify and manage them.
  • Ensure that the statically-configured IPs do not conflict. It is recommended that you let the VPC dynamically set the IP addresses on your cluster vNICs. This way, you can be assured the IPs will not conflict with any of the VPC default address prefixes.