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

These are the prerequisites for this scenario:

You must have VirtualCenter 2.x.

You must have vCenter Update Manager.

All your hosts must be ESX 3.x or ESXi 3.5. You cannot upgrade from ESX 3.5 Update 5 to ESX 4.0. However, you can upgrade from ESX 3.5 Update 5 to ESX 4.0 Update 1 or later.

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


Upgrade VirtualCenter 2.x to vCenter Server 4.0.


Make sure your database is compatible with vCenter Server 4.0. This release discontinues support for some database versions and adds support for other database versions. See the Compatibility Matrixes on the VMware vSphere documentation Web site.


Make sure that you have the required permissions to perform this procedure. See Database Prerequisites.


Take a full backup of the VirtualCenter 2.x database. See your database documentation.


Back up the VirtualCenter 2.x SSL certificates. See Back Up VirtualCenter 2.x.

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. The upgrade from VirtualCenter 2.5 is faster in comparison to the upgrade from VirtualCenter 2.0.x because of differences in changes to the database schema and the amount of data migration.

After the upgrade, the ESX hosts are automatically reconnected to vCenter Server 4.0. Your VMware High Availability (HA) and VMware 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.)

For a detailed description of the upgrade procedure, see Preparing for the Upgrade to vCenter Server and Upgrading to vCenter Server 4.0.


Run the vCenter Agent Preupgrade Check tool.


Install the vSphere Client.

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

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


If your environment has vCenter Converter, upgrade it to the latest version.


If your environment has vCenter Guided Consolidation, complete the consolidation plan and then upgrade it to the latest version.


Upgrade to vCenter Update Manager 4.0.


Use vCenter Update Manager to upgrade ESX 3.x/ESXi 3.5 hosts to ESX 4.0/ESXi 4.0.

vCenter 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.

In case of upgrade failure, vCenter Update Manager supports rollback to the previous release.

For a detailed description of the procedure, see the vCenter Update Manager Administration Guide.


Use vCenter Update Manager to upgrade your virtual machines. vCenter 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. vCenter Update Manager also performs automatic backups of your virtual machines in case you need to roll back after the upgrade. You can upgrade 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.