Add Hosts to a Cluster that Uses a Single Image

Starting with vSphere 7.0 Update 2, when you add hosts to a cluster, you can appoint one of those hosts as a reference host. vSphere Lifecycle Manager extracts and uses the image on the reference host as the new image for the cluster. The option to import a host's image to the cluster facilitates and simplifies the cluster upgrade operation by removing the need for you to manually import components to the vSphere Lifecycle Manager depot, set up and validate a new image, check the compliance of the hosts against the image, and then remediate the cluster against the image to apply the new software specification to all hosts.

Along with extracting the software specification from the appointed reference host, vSphere Lifecycle Manager also extracts the software depot associated with the image, and imports the components to the vSphere Lifecycle Manager depot in the vCenter Server instance where the target cluster is.

Note: When you import an image from a host, vSphere Lifecycle Manager retrieves the ESXi version, vendor add-on, and user-added components from the host. vSphere Lifecycle Manager does not extract the components from solutions and firmware updates installed on the reference host. Therefore, the new image for the cluster does not contain solution components or a firmware and drivers add-on. To obtain firmware updates in the depot and add a firmware and drivers add-on to your cluster image, you must configure a hardware support manager. For more information about firmware updates, see Firmware Updates.

Adding a host to a cluster and importing its image to the target cluster changes the compliance state of the other hosts in the cluster. After adding the host and setting its image as the new cluster image, you can run a compliance check. The newly added host is compliant against the new cluster image. The rest of the hosts become non-compliant. To apply the new cluster image to all the hosts in the cluster and make them compliant, you must remediate the cluster.

Note: You cannot downgrade the software that is actually installed on the hosts in the cluster. If the image on the reference host contains software components of lower version, you can still import and use that image for the cluster. However, the hosts in the cluster become incompatible with the new image, and you cannot proceed and remediate the cluster against that image.

Prerequisites

Verify that the vCenter Server version is 7.0 or later.
Verify that the hosts to add are of version ESXi 7.0 or later.
Verify that the hosts that you add to the cluster are of the same main and patch version as the rest of the hosts.
Obtain the user name and password of the root user account for the hosts that are not in your vCenter Server instance.
Review the requirements for using a single image in System Requirements for Using vSphere Lifecycle Manager.
To add a host and import its image to the cluster, verify that the following requirements are met.
- The vCenter Server instance is of version 7.0 Update 2 or later
- The ESXi version on the reference host is 7.0 Update 2 or later

Procedure

In the vSphere Client, navigate to the Hosts and Clusters inventory.
Right-click cluster and select Add Hosts.
The Add Hosts wizard opens.
On the Add hosts, specify the hosts that you want to add to the cluster and click Next.
- Add a host that is not in the same vCenter Server inventory.
  1. Click the New Hosts tab.
  2. Enter the required information about the host in the text boxes.
  3. To add more new hosts, click the Add Host button and enter the required information.
  4. Select the Use the same credentials for all hosts check box.
- Add a host that is in the same vCenter Server inventory.
  1. Click the Existing hosts tab.
  2. Select one or multiple hosts from the list.
Note: If you want to add multiple hosts, you do not need to specify only new hosts or only existing hosts. You can specify new hosts and select from the existing hosts at the same time.
On the Host Summary page, review the information about the hosts and click Next.
On the Import Image page, select the host whose image to use as the image for the cluster.
- To add the specified hosts to the cluster without changing the current image for that cluster, select the Don't import an image radio button.
- To use any of the specified hosts as a reference host and use its image as the new image for that cluster, select the Select which host to import the image from radio button and select a host from the list.
  Note: If the image on the host that you select is of version earlier than ESXi 7.0 Update 2, you cannot proceed with importing the image from that host.
When you select a host to import an image from, a card with information about the image appears. you can view the ESXi version, the vendor add-on, and the additional components that the image on the reference host contains.
If you selected the Select which host to import the image from radio button, click Show Cluster's Current Image at the bottom of the page.
A card with information about the current image for the cluster appears. Before you proceed, you can review and compare the current cluster image with the image on the selected host before you proceed. In this way, you can ensure that you selected the right reference host.
Click Next.
On the Ready to Complete page, review the information about the selected hosts and the new cluster image.
Click Finish to add the hosts to the cluster.

Results

The specified hosts are added to the cluster.

If you chose to import an image from a host during the host addition procedure, the image for the cluster changes. The new software specification for the cluster is identical to the one on the selected and added reference host.

What to do next

If you chose to import an image from a host during the host addition procedure, remediate the cluster to apply the new image to all the hosts.