You can create custom groups of virtual machine hosts, known as host groups, for grouping hosts and their virtual machines in a meaningful way. You can also use host groups to set aside resources on hosts in the host group for the use of the host operating system. Host groups are represented by folders in the navigation pane of the Hosts view and Virtual Machines view. Host groups are created by using the New host group action in both of those views.
When you add a VMware VirtualCenter Server, all existing hosts for that server are also added and automatically placed into host groups that match the datacenter hierarchy on the server. A host group is created for each folder and host cluster within each datacenter. VMware ESX servers must remain within their parent host group or a child of that host group. If a new datacenter is subsequently added, it appears as a new host group in Virtual Machine Manager (VMM) the next time the VMware VirtualCenter Server is refreshed.
Ways to Use Host Groups
The following list describes ways that you can create and use host groups to organize hosts for your environment:
- Basic organization when managing large
numbers of hosts and virtual machines—You can create custom
views within the Hosts view and Virtual Machines view to provide
easy monitoring and access to host groupings of your choice. For
example, you might create a host group for each branch office in
- Reserving resources for use by
hosts—Host reserves are useful when virtual machines are placed
on a host. The host reserves determine the amount of CPU, memory,
disk space, disk I/O capacity, and network capacity that will
always be available to the host operating system. Use the Host
group properties action for the root host group, All Hosts, to
set default host reserves for all hosts managed by Virtual Machine
Manager. If you want to use the resources on some hosts more fully
than on other hosts, you can set host reserves differently for each
- Designating hosts on which users can
create and operate their own virtual machines—When a VMM
administrator adds self-service roles, the role identifies the
hosts on which self-service users or groups in that role are
allowed to create, operate, and manage their own virtual machines.
This process is known as virtual machine self-service. It is
easier to designate such hosts if a specific host group is created
for this purpose. For more information, see About Virtual Machine
- Implementing Performance and Resource
Optimization (PRO)—PRO is implemented for individual host
groups and host clusters. For more information, see About Performance and
Resource Optimization (PRO).
Creating a Host Group Hierarchy
Host groups are hierarchical. You can create a child host group within another host group. You can also add child host groups to a parent host group by using the Move action or by dragging host groups and dropping them into a parent host group. All host groups and all hosts belong to the All Hosts root host group, which is created during installation.
Inheritance of Host Group Settings
Within the host group hierarchy, child host groups can inherit settings from their parent host group.
The inheritance results from host group actions are explained in the following table.
|Host group action||Host reserves settings||PRO settings|
Create a new child host group within a parent host group or the root parent group All Hosts
Child host group inherits the host reserve settings from its parent host group
Child host group inherits the PRO settings from its parent host group
Add a child host group to a parent host group or the root parent group All Hosts
Child host group does not inherit the host reserve settings from its parent host group
Child host group inherits the PRO settings from its parent host group if the Inherit PRO setting from parent Host Group check box is selected for the child host group
Change the settings of a parent host group or the root parent group All Hosts
You are given the option to apply host reserve changes to only the parent host group or to cascade the revised settings down to all child host groups
Child host groups inherit the PRO settings from its parent host group if the Inherit PRO setting from parent Host Group check box is selected for the child host group
For the most up-to-date Help information, go to the Virtual Machine Manager 2008 Help Online. To find additional Virtual Machine Manager 2008 documentation, go to the Virtual Machine Manager 2008 TechCenter Library.