Orchestrated upgrades allow you to upgrade the objects in your vSphere inventory in a two-step process: host upgrades followed by virtual machine upgrades. You can configure the process at the cluster level for higher automation, or you can configure it at the individual host or virtual machine level for granular control.

For example, you can define a host upgrade baseline to upgrade an ESX 3.5 host to ESX 4.1, or you can define a virtual machine upgrade baseline to upgrade the VMware Tools and the virtual machine hardware to the latest version. To do this, you use wizard-based workflows to first schedule host upgrades for an entire cluster and then schedule a virtual machine upgrade for all the virtual machines.

Built-in best practices in the wizard workflows preclude erroneous upgrade sequences. For example, the wizard prevents you from upgrading virtual machine hardware before you upgrade hosts in a cluster.

You can use Distributed Resource Scheduler (DRS) to prevent virtual machine downtime during the upgrade process.

Update Manager monitors hosts and virtual machines for compliance against your defined upgrade baselines. Noncompliance appears in detailed reports and in the dashboard view. Update Manager supports mass remediation.

See the VMware vCenter Update Manager Installation and Adminstration Guide accessible on the VMware vCenter Update Manager Documentation page: http://www.configuresoft.net/support/pubs/vum_pubs.html.