Remediation is the process in which VMware vSphere Update Manager applies patches, extensions, and upgrades to vSphere objects in groups. To take advantage of improvements in virtual hardware in vSphere 5.0, you can use Update Manager to update groups of virtual machines at one time.

The scenario in this example demonstrates the basic workflow for remediating virtual machines when virtual hardware upgrades become available.

All virtual machines have a hardware version. The hardware version indicates which virtual hardware features the virtual machine supports, such as BIOS or EFI, number of virtual slots, maximum number of CPUs, maximum memory configuration, and other hardware characteristics. The version of the ESXi host on which you have created the virtual machine determines the virtual machine hardware version.

vSphere 5.0 introduces hardware version 8. One example of added capability is that hardware version 8 supports up to 32 virtual CPUs instead of the previous number of 8 CPUs in hardware version 7. Although you might have updated your hosts with vSphere 5.0, the hardware version of the virtual machines is not automatically updated at that time. Without remediation, the virtual machines would continue to support only 8 CPUs.

Upgrading the virtual machines individually to hardware version 8 is tedious and inefficient. This is where remediation can help.

The remediation path for applying the hardware upgrade to your virtual machines consists of choosing your baseline and baseline group, evaluating your virtual machines against that baseline, and upgrading the virtual machines to bring them into compliance with the configuration defined by the baseline.

By default, Update Manager takes snapshots of virtual machines before applying updates. If the remediation fails, you can use the snapshot to return the virtual machine to the state before the remediation.

Using Baselines and Baseline Groups

Baselines contain a collection of one or more patches, extensions, service packs, bug fixes, or upgrades. Update Manager has default upgrade baselines, one of which is VM Hardware Upgrade to Match Host (Predefined), for checking the virtual hardware of a virtual machine for compliance with the latest version supported by the host.

To streamline the upgrade process even more, you can have Update Manager do an orchestrated upgrade of virtual machines, which includes the upgrade of VMware Tools through the VMware Tools Upgrade to Match Host baseline.

You assemble baseline groups from existing baselines. When you scan virtual machines, you evaluate them against baselines and baseline groups to determine their level of compliance.

Scanning Virtual Machines

Scanning is the process in which attributes of a set of hosts, virtual machines, or virtual appliances are evaluated against all patches, extensions, and upgrades in the attached baselines or baseline groups, depending on the type of scan you select. You can scan a virtual machine to determine whether it is up to date with the latest virtual hardware or VMware Tools version. When you select the Virtual machine hardware upgrade scan, you can scan virtual machines running Windows or Linux for the latest virtual hardware supported on the host. You can perform hardware-upgrade scans on online as well as offline virtual machines.

Remediating Virtual Machines

With remediation, Update Manager applies patches, extensions, and upgrades to hosts, virtual machines, or virtual appliances after a scan is complete. You can manually remediate virtual machines against baseline groups containing upgrade baselines.

For information about Update Manager and its functions, see the Installing and Administering VMware vSphere Update Manager documentation.