When you plan on using the OpenStack Bare Metal provisioning service (Ironic), consider the following limitations:

Specific hardware limitations
When choosing hardware (switch) to be used by Ironic, consider hardware limitations of a specific vendor.
Only iSCSI deploy drivers are enabled

Ironic is deployed with only iSCSI deploy drivers enabled which may pose performance limitations for deploying multiple nodes concurrently. You can enable agent-based Ironic drivers manually after deployment if the deployed cloud has a working Swift-compatible object-store service with support for temporary URLs, with Glance configured to use the object store service to store images. For more information on how to configure Glance for temporary URLs, see OpenStack documentation.