Installation guide

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.
7 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.
8 Upgrade your product licenses:
a Either your new license keys are sent to you in email, or you get them using the license portal.
b Apply the new license keys to your assets using vCenter Server.
Upgrading Environments Without Host Clusters
If you have standalone ESX 3.x/ESXi 3.5 hosts, you can use vSphere Host Update Utility to upgrade your hosts
and the vSphere Client to upgrade your virtual machines.
This scenario assumes that you do not have host clusters and you do not have vCenter Update Manager. In
such a case, you probably do not have VirtualCenter either. If you do have VirtualCenter, the following process
can apply to your environment as well.
The following list of tasks provides a high-level overview of the upgrade process.
1 If you have VirtualCenter, upgrade VirtualCenter 2.x to vCenter Server 4.0.
a 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.
b Make sure that you have the required permissions to perform this procedure. See “Database
Prerequisites,” on page 39.
c Take a full backup of the VirtualCenter 2.x database. See your database documentation.
d Back up the VirtualCenter 2.x SSL certificates. See “Back Up VirtualCenter 2.x,” on page 43.
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.
For a detailed description of the upgrade procedure, see Chapter 5, “Preparing for the Upgrade to vCenter
Server,” on page 37 and Chapter 6, “Upgrading to vCenter Server 4.0,” on page 45.
2 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.
During vSphere Client installation, install the vSphere Host Update Utility. By default, this utility is not
installed. Install it if you plan to use this Windows machine to initiate host upgrades.
For a detailed description of the procedure, see “Upgrade to the vSphere Client,” on page 56.
3 If your environment has vCenter Converter, upgrade it.
Chapter 2 Example Upgrade Scenarios
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