One of the more essential and yet underrated tasks associated with using System Center Virtual Machine Manager (VMM) to manage your virtualization infrastructure is organizing the virtualization hosts into host groups. For those who may not be familiar with the concept of host groups, they are essentially just a collection of containers that serve as a way of organizing virtualization hosts. VMM contains one default host group called All Hosts, and in smaller organizations, it is perfectly acceptable to use this default host group in perpetuity. However, larger organizations will almost always find that they need to develop some sort of organizational structure for their virtualization hosts. Otherwise, the host can become difficult to manage.
The image above shows what the default host group looks like. You can create additional host groups by simply right-clicking on All Hosts and then choosing the Create Host Group command from the shortcut menu, as shown below. Upon doing so, you will simply need to provide a name for the host group that you are creating.
Create entire hierarchies of host groups
As you can see below, any host groups you create exist as child objects beneath the All Hosts group. It is worth noting that you can create entire hierarchies of host groups by creating host groups within other host groups.
Even though the process of creating host groups is really simple and straightforward, planning your host group structure does require a bit of effort. The good news, however, is that you can change the host group structure at any time. Suppose, for instance, that you create a collection of host groups and then, later on, decide that they are no longer meeting your needs. You could create an entirely new host group structure, move the virtualization hosts into the new host groups, and then delete the original host groups. In other words, when you choose a host group structure, you aren’t locked into using it forever. You can make modifications to your host groups as your needs change.
This, of course, raises the question of how you should structure your host groups. Unfortunately, there is no such thing as a universally applicable answer to this question. Every organization has different needs, so a host group structure that works for one organization might not necessarily be a good fit for another organization. That being the case, I want to share with you several common approaches for creating host group structures.
Mimic the Active Directory topology
One of the most commonly used strategies for creating host groups within VMM is to mimic the organization’s Active Directory topology. The idea behind this approach is that larger organizations rarely have a flat Active Directory. More often, the Active Directory is organized into sites, domains, and organizational units. The structures can be easily mimicked within the host group collection. For example, an organization might choose to create a separate host group for each one of its Active Directory domains and then place the virtualization hosts residing within each domain into the corresponding host group.
Organize hosts groups by geography
Another commonly used strategy is to organize host groups based on geography. There are countless variations to this technique because geography means different things in different organizations.
A really simple example might be an organization with offices in Miami, Las Vegas, and New Orleans. An administrator might create a separate VMM host group for each city and then place the virtualization hosts within those cities into the corresponding host groups.
Another way geographic location can be used in the establishment of host groups is to base the host group structure on branch offices. For instance, if an organization has ten branch offices, it might create ten host groups, one for each branch office. It doesn’t really matter if some branch offices don’t have any virtualization hosts in them. An empty host group can still be created purely for the sake of keeping things organized. That way, if a virtualization host is added to a branch office later on, then the required infrastructure is already in place.
Of course, it is also possible to combine the two different techniques that I just described. Imagine that a huge company has offices all around the world and that there are multiple branch offices in some cities. In this case, an organization might benefit from a multitier host group hierarchy. This hierarchy might contain host groups referencing continents, countries, cities, and locations. The path to a particular branch office in New York City might look like this: North America / USA / New York / 9th Street.
Although organizing host groups by geography works really well for huge companies, the approach can also be used for much smaller organizations. I once saw an organization that occupied three floors of a large office building and created a separate host group for each floor. While this is technically a geographic approach to organization, the organization essentially based its host group structure on department.
Organize hosts by function
Yet another approach that is sometimes used is to create host groups based on the purpose of the hosts within those groups. An organization might, for instance, create one host group for the production environment and another host group for the Dev / Test environment.
Group hosts by host type
One last option that I want to be sure to mention is that you can base your host group structure on hosts type. This is the organizational method that I use in my own environment. Before I show you how this works, I need to point out that this method isn’t really suitable for large organizations.
The reason why I have host groups organized by host types is because I have a small collection of Hyper-V hosts and a couple of VMware hosts. All of these hosts are managed by VMM, but I wanted to keep my VMware hosts separate from my Hyper-V hosts. The host group structure worked perfectly for this purpose.
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