OpenStack Cinder NVMe/TCP Multipathing: Only One Controller Path Visible with NetApp ONTAP

Applies to

• NetApp ONTAP (e.g., 9.17.1P6, AFF-C250)
• OpenStack Cinder using NetApp ONTAP NVMe/TCP unified driver
• Linux hosts with native NVMe multipath enabled
• OpenStack deployments (e.g., Platform9) using os-brick for NVMe/TCP
• Multi-controller NetApp clusters with multiple NVMe/TCP LIFs

Issue

When attaching a NetApp ONTAP NVMe/TCP volume to a VM using OpenStack Cinder, only one NVMe/TCP path/controller is automatically established on the compute node. As a result, multipathing and redundancy are not available by default. Manual discovery and connection to the second LIF is required to establish the additional path.

Example log output (from cinder-volume and os-brick):

DEBUG cinder.volume.drivers.netapp.dataontap.nvme_library Initialize connection info: {
  'driver_volume_type': 'nvmeof',
  'data': {
    'target_nqn': 'nqn.1992-08.com.netapp:...',
    'host_nqn': 'nqn.2014-08.org.nvmexpress:uuid:...',
    'portals': [('<nvme data lif ip1>', 4420, 'tcp')],
    'vol_uuid': '...'
  }
}

DEBUG cinder.volume.manager Connection info returned from driver {
  'target_nqn': 'nqn.1992-08.com.netapp:...',
  'host_nqn': 'nqn.2014-08.org.nvmexpress:uuid:...',
  'portals': [('<nvme data lif ip2>', 4420, 'tcp')],
  ...
}

DEBUG os_brick.initiator.connectors.nvmeof Found a valid portal at ('<nvme data lif ip1>', '4420', 'tcp', ...)
DEBUG os_brick.initiator.connectors.nvmeof Skipping ('<nvme data lif ip2>', '4420', 'tcp', ...), not part of portals [...]

Expected: Both LIFs should be returned in the portals list.