Host preparation is the process in which the NSX Manager 1) installs NSX kernel modules on ESXi hosts that are members of vCenter clusters and 2) builds the NSX control-plane and management-plane fabric. NSX kernel modules packaged in VIB files run within the hypervisor kernel and provide services such as distributed routing, distributed firewall, and VXLAN bridging capabilities.

To prepare your environment for network virtualization, you must install network infrastructure components on a per-cluster level for each vCenter Server where needed. This deploys the required software on all hosts in the cluster. When a new host is added to this cluster, the required software is automatically installed on the newly added host.

If you are using ESXi in stateless mode (meaning that ESXi does not actively persist its state across reboots), you must download the NSX Data Center for vSphere VIBs manually and make them part of the host image. You can find the download paths for the NSX Data Center for vSphere VIBs from the page: https://<NSX_MANAGER_IP>/bin/vdn/ Download paths can change for each release of NSX Data Center for vSphere. Always check the https://<NSX_MANAGER_IP>/bin/vdn/ page to get the appropriate VIBs. For more information, see the VMware knowledge base article "Deploying VMware NSX for vSphere 6.x through Auto Deploy" at


  • Register vCenter Server with NSX Manager and deploy the NSX Controller cluster.

  • Verify that a reverse DNS lookup returns a fully qualified domain name when queried with the IP address of NSX Manager.

  • Verify that hosts can resolve the DNS name of vCenter Server.
  • Verify that hosts can connect to vCenter Server on port 80.
  • Verify that the network time on vCenter Server and ESXi hosts is synchronized.
  • For each host cluster that participates in NSX, verify that all hosts within the cluster are attached to a common vSphere Distributed Switch (VDS).

    For instance, say that you have a cluster with Host1 and Host2. Host1 is attached to VDS1 and VDS2. Host2 is attached to VDS1 and VDS3. When you prepare a cluster for NSX, you can only associate NSX with VDS1 on the cluster. If you add another host (Host3) to the cluster and Host3 is not attached to VDS1, it is an invalid configuration, and Host3 will not be ready for NSX functionality.

  • If you have vSphere Update Manager (VUM) in your environment, you must disable it before preparing clusters for network virtualization. For information about verifying if VUM is enabled and how to disable it if necessary, see
  • If your network contains vSphere 7.0 or later, verify that the vCenter clusters do not use a vSphere Lifecycle Manager (vLCM) image to manage ESXi host life-cycle operations. Host preparation is not allowed on vCenter clusters that use a vLCM image.

    To verify whether a vLCM image is used to manage hosts in the cluster, log in to the vSphere Client and go to Hosts and Clusters. In the navigation pane, click the cluster, and navigate to Updates > Image. If a vLCM image is not used on the cluster, you must see the SetUp Image button. If a vLCM image is used on the cluster, you can view the image details, such as ESXi version, vendor add-ons, image compliance details, and so on.

    When a vCenter cluster has no hosts added to it, and NSX is installed, you can still configure the empty cluster to use a vLCM image. However, later when you add hosts to this cluster, and prepare the hosts for NSX, host preparation will fail. This behavior is a known issue. Therefore, you must avoid using a vLCM image on an empty vCenter cluster that has NSX installed.

  • Starting with version 6.4.2, when you install NSX Data Center for vSphere on hosts that have physical NICs with ixgbe drivers, Receive Side Scaling (RSS) is not enabled on the ixgbe drivers by default. You must enable RSS manually on the hosts before installing NSX Data Center. Make sure that you enable RSS only on the hosts that have physical NICs with ixgbe drivers. For detailed steps about enabling RSS, see the VMware knowledge base article at This knowledge base article describes recommended RSS settings for improved VXLAN packet throughput.
  • Before beginning the host preparation process, always make sure that the Resolve option does not appear, or is dimmed, in the cluster's Actions list.

  • The Resolve option sometimes appears because one or more hosts in the cluster must be rebooted.

    Other times the Resolve option appears because there is an error condition that must be resolved. Click the Not Ready link to view the error. If you can, clear the error condition. If you cannot clear an error condition on a cluster, one workaround is to move the hosts to a new or different cluster and delete the old cluster.

If Resolve option does not fix the problem, refer to NSX Troubleshooting Guide. To see list of problems that are resolved by the Resolve option, refer to NSX Logging and System Events.


  1. Using the vSphere Web Client, log in to the vCenter Server system registered with the NSX Manager that will become the primary NSX Manager.
    If the vCenter Server systems in your cross-vCenter NSX environment are in Enhanced Linked Mode, you can access any associated NSX Manager from any linked vCenter Server system by selecting it from the NSX Manager drop-down menu.
  2. Navigate to Networking & Security > Installation and Upgrade > Host Preparation.
  3. For all clusters that require NSX Data Center for vSphere switching, routing, and firewalls, select the cluster and click Actions > Install.

    A compute cluster (also known as a payload cluster) is a cluster with application VMs (web, database, and so on). If a compute cluster has NSX Data Center for vSphere switching, routing, or firewalls, you must install NSX Data Center for vSphere on the compute cluster.

    In a shared "Management and Edge" cluster, NSX Manager and NSX Controller VMs share a cluster with edge devices, such as distributed logical routers (DLRs) and edge services gateways (ESGs). In this case, you must install NSX on the shared cluster.

    Conversely, if Management and Edge each has a dedicated, non-shared cluster, as is recommended in a production environment, install NSX on the Edge cluster but not on the Management cluster.

    Note: While the installation is in progress, do not deploy, upgrade, or uninstall any service or component.
  4. Monitor the installation until the NSX Installation or Installation Status column displays a green check mark.
    If the column says Not Ready, click Actions > Resolve. Clicking Resolve might result in a reboot of the host. If the installation is still not successful, click Not Ready. All errors are displayed. Take the required action and click Resolve again.
    When the installation is complete, the NSX Installation or Installation Status column displays the version and build of NSX installed and the Firewall column displays Enabled. Both columns have a green check mark. If you see Resolve in the NSX Installation or Installation Status column, click Resolve and then refresh your browser window.
    Caution: In a network that contains vSphere 7.0 or later, after the host clusters are prepared for NSX, you cannot use a vLCM image on the vCenter clusters. If you try to use a vLCM image on the vCenter clusters, warning messages are displayed in the vSphere Client to inform you that standalone VIBs are present on the hosts.


VIBs are installed and registered with all hosts within the prepared cluster.

To verify, SSH to each host and run the esxcli software vib list command and check for the relevant VIBs. In addition to displaying the VIBs, this command shows the version of the VIBs installed.

[root@host:~] esxcli software vib list | grep nsx
esx-nsxv      6.0.0-0.0.XXXXXXX    VMware  VMwareCertified   2018-01-16

If you add a host to a prepared cluster, the NSX Data Center for vSphere VIBs are automatically installed on the host.

If you move a host to an unprepared cluster, the NSX Data Center for vSphere VIBs are automatically uninstalled from the host.