This example scenario shows how you can use vSphere Update Manager to simplify the host and virtual machine upgrade process and minimize downtime in environments that include host clusters.

For this scenario, verify the following details about your vSphere environment.

You must have vCenter Server 4.x or vCenter 5.0.x.

You must have vSphere Update Manager.

All your hosts must be ESX 4.x/ESXi 4.x or later.

If your environment has vCenter Guided Consolidation, uninstall it before upgrading.

The following list of tasks provides a high-level overview of the upgrade process.


Run the vCenter Host Agent Pre-Upgrade Checker.


Upgrade vCenter Server 2.5 Update 6 or higher, vCenter Server 4.x, or vCenter 5.0 to vCenter Server 5.1.


Make sure your database is compatible with vCenter Server 5.1. See the VMware Product Interoperability Matrix at


Make sure that you have the required permissions to perform this procedure. See Prerequisites for the vCenter Server Upgrade.


Take a full backup of the vCenter Server database. See your database documentation.


Back up the vCenter Server SSL certificates.

The downtime required for this upgrade is based on the amount of data in the database. During this time, you cannot perform provisioning operations, such as cloning or creating virtual machines.

After the upgrade, the hosts are automatically connected to vCenter Server 5.1 if you select that option during the upgrade process. vSphere High Availability (HA) and vSphere Distributed Resource Scheduler (DRS) clusters are automatically reconfigured. (Check to ensure that the automatic reconfiguration is successful. In some cases, you might need to reconfigure the clusters manually.)

vCenter Server 5.x is supported only on 64-bit systems. The upgrade method you use depends on what version of vCenter Server you are upgrading and on what system it is currently installed. For a detailed description of the upgrade procedure, see Preparing for the Upgrade to vCenter Server and Upgrading to vCenter Server 5.1.


Install the vSphere Client.

You can install the vSphere Client on the same machine with your previous version of the vSphere Client. You must have the previous version of the vSphere Client to connect to previous versions of vCenter Server and ESX/ESXi.

For a detailed description of the procedure, see Upgrade the vSphere Client.


Upgrade vSphere Update Manager to vSphere Update Manager 5.1.


Use Update Manager to upgrade ESX 4.x/ESXi 4.x or higher hosts to ESXi 5.1.

Update Manager puts the host into maintenance mode before upgrading the host. The downtime for the procedure depends on the network speed and the server boot time.

For a detailed description of the procedure, see the Installing and Administering VMware vSphere Update Manager documentation.


Use Update Manager to upgrade your virtual machines. Update Manager ensures that the VMware Tools upgrade and the virtual hardware upgrade happen in the correct order to prevent loss of your network connectivity. Update Manager also performs automatic backups of your virtual machines in case you need to roll back after the upgrade. You can upgrade hosts in clusters without powering off the virtual machines if Distributed Resource Scheduler is available for the cluster.


Upgrade your product licenses:


Either your new license keys are sent to you in email, or you get them using the license portal.


Apply the new license keys to your assets using vCenter Server.


Use the vSphere Client to upgrade to VMFS5.

See the information on upgrading datastores to VMFS5 in the vSphere Storage documentation.