Starting with NSX-T 3.2.1, during the host migration step, you can add or remove a host to be migrated when there is a pause in the migration.

Starting with NSX-T 3.2.2, you can pause the migration of hosts within a group. For more information, see Configuring NSX-V Host Migration.

Host migration will pause if you enable the setting Pause Between Groups or Pause Between Hosts, or if there is a failure to migrate a host.

You can add a host to a cluster before or after the cluster has been migrated, or while the cluster is being migrated. You can also remove a host from a cluster that has not migrated or is being migrated.

The host you want to add can be a standalone host or in a cluster. The host must not have NSX-V or NSX-T configured. If the host is in a cluster, the cluster must not have NSX-V or NSX-T configured.

You must prepare the host as a transport node first and later move it into a target cluster that has been migrated to NSX-T, is being migrated or has not started the migration. If the target cluster already has a host migrated to an NSX-T transport node, you can use the transport node's configuration as a reference to prepare the host as a transport node. If the host will support overlay traffic and a VTEP IP pool will be used to prepare the host as a transport node, the VTEP IP pool cannot be or overlap with the VTEP IP pool created for the NSX-V hosts being migrated or to be migrated. It can be an existing IP pool (such as the one used by NSXT Edge nodes) or a newly created IP pool. For more information, see the section "Preparing ESXi and KVM Hosts as Transport Nodes" in the NSX-T Data Center Installation Guide.

When preparing an ESXi host as a transport node, you can choose N-VDS or VDS as the host switch. Choose VDS if the version of the VDS being migrated is 7.0 or later. Otherwise, choose N-VDS. If you prepare a host with N-VDS when you should choose VDS, the host will still be migrated but it may have network issues.

Adding a host to a cluster

  1. From vCenter Server, put the host in Maintenance Mode.
  2. If there is no VTEP IP pool that does not overlap with the VTEP IP pool created for the NSX-V hosts being migrated or to be migrated, or such pools do not have enough free IPs for the VTEPs to be created for the host to be added, then go to Networking > IP Address Pools and create a new VTEP IP pool.
  3. Follow the instructions in the installation guide to prepare the host as a transport node. When you select the transport zone, if an overlay transport zone is chosen for the host switch, choose the new IP pool that was created in step 2 or choose an existing IP pool that does not overlap with the VTEP IP pool created for the NSX-V hosts being migrated or to be migrated. Select an uplink profile. Do not choose the one whose name contains "VXLAN" if an overlay transport zone is chosen for the host switch.
  4. Wait for the status of the host node to be "Success". Do not move the host out of Maintenance Mode.
  5. Choose a cluster into which the host will be added. In NSX-T Manager UI, go to System > Fabric > Nodes > Host Transport Nodes (if the NSX-T version is 3.2.0 or 3.2.1) or System > Fabric > Hosts (if the NSX-T version is 3.2.2 or later) and check if the cluster has a Transport Node Profile (TNP) attached. Detach the TNP if it does.
  6. In vCenter Server UI, move the host into the chosen cluster.
  7. Invoke the sync host groups API or click the Refresh button on the NSX-T Manager UI host migration screen so that the migration group for the cluster contains the new host.
  8. Call the following NSX-T API to accept the new host:
    POST https://{nsxt-mgr-ip}/api/v1/migration/setup?action=migrate_newly_added_host_transport_node
{
    "host_transport_node_id" : "<transport-node-uuid>"
}

    If the API returns an error, fix the error and retry the API. If the API returns success, then make the host exit maintenance mode.

  9. vMotion VMs to the host. If any VM is moved from an NSX-V host, be sure to change the network to map the source virtual-wire to NSX-T overlay segments. For example, virtual-wire vxw-dvs-64-virtualwire-4-sid-10787-1-switch-191 must map to 1-switch-191-LS.

Removing a host from a cluster

  1. From vCenter Server, migrate all VMs off the host and enter the host into maintenance mode.
  2. If the host is in a cluster that has not started migrating, go to the next step. Otherwise, from NSX-T Manager UI, go to System > Fabric > Nodes > Host Transport Nodes (if the NSX-T version is 3.2.0 or 3.2.1) or System > Fabric > Hosts (if the NSX-T version is 3.2.2 or later). If the host has NSX configured, delete it. If the host is not reachable by NSX Manager, delete it with the force option.
  3. From vCenter Server, remove the host. Wait until the task is complete.
  4. Click the Refresh button on the host migration screen to remove the host from the migration group.
  5. Restart the host migration.