Chargeback speaks in the universal language of money to put IT and business managers on the same page when it comes to managing the virtual machine lifecycle.
To understand how virtual machine resources are
being used in your organization, follow the money.
Assigning costs to IT assets in the virtual
world is so different from the physical-only model that data centers are
leaving behind that special tools must be brought in to sniff out the money trail.
Thus far, the drastic cost reductions made possible by server consolidation,
along with the complexity that virtualization introduces in the form of easy
virtual machine migration among physical assets have resulted in a meager
choice of chargeback tools.
vCenter Chargeback version 1.6.1, which was released in July and has a suggested price
of $1,250 for a 25 VM pack. vCenter Chargeback can actually be used for either
showback or chargeback.
Chargeback and Showback
Before getting into the mechanics of vCenter
Chargeback, it's important to understand the difference between chargeback and showback
and when an IT manager might consider one approach over the other.
Formal chargeback, according to most vendors in
the space, is fairly uncommon because the cost numbers provided usually must conform
to generally accepted accounting principles. These principles are quite strict
when it comes to associating costs with physical assets including servers,
storage arrays and network equipment, which have definite depreciation rates.
Further, many of these physical assets have come with tax implications that
govern how the value of the equipment is measured.
For example, if a virtual machine runs on
physical server A and then moves to physical server B, neither of which are at
the same point in the depreciation process, it is a nontrivial problem to
figure out how much to charge the department using the virtual machine.
Furthermore, a practical chargeback system must
be integrated with an internal accounting system so that bills can be presented
Showback is an informal way of associating estimated
costs for virtual machine operation without any money changing hands, thereby
avoiding the sticky accounting rules. Reports can be provided to managers as a
guide to budgeting decisions without entering the regulated world of tax
How We Tested
I installed the vCenter Chargeback application
on a virtual machine running Windows Server 2003 R2 in the eWEEK
VMware vSphere 5 test environment. The physical hosts were a mix of Hewlett-Packard
and Acer systems. After installing Microsoft SQL Server 2008 on the virtual
machine, I installed vCenter Chargeback and configured it to connect to our vCenter
I started with a simple fixed-cost model by
defining a template where I filled in values for rate factors. IT managers will
need to work with facilities and accounting staffs to ensure that the myriad detailed
costs are entered correctly. Organizations that have facilities spread across
geographic regions should consider that costs for various resources would vary
by region. vCenter Chargeback can take these variations into account, but that
means that IT will need to input these cost factors at set-up time.
The vCenter Chargeback model uses two user-defined
modules called billing policy and base rate to determine costs. IT managers who
are new to performing chargeback should plan on spending several hours each
month for at least two to three months making adjustments to the base rate and
rate factors in order to fine-tune the cost model. In my case, I entered
conservative base-rate information for a number of computing resources in my
environment, including CPU (measured in GHz per hour), disk reads and
writes, memory (measured in GBs per hour), network I/O and storage.
At the end of the configuration process, vCenter
Chargeback used the information I provided to run reports on my VM usage as
monitored by the vCenter Server.
vCenter Chargeback reports are comprehensive in scope
and will take some getting used to for IT managers who are new to chargebacks.
For example, because asset use is measured by the hour and varies by the time
of day, vCenter Chargeback is able to prorate usage in order to provide fairly
accurate billing information. Accuracy will increase the longer the virtual
machine is running as most vCenter Chargeback measures are hourly, not by the
I was also able to use vCenter Chargeback to
create variable-cost reports. These reports required more extensive cost
information and schedule data. I used the variable-cost reports modules to
compare operational costs across different times of the day and different
vCenter Chargeback administration should be
adequate for most organizations. I was able to create users who ranged from
super users with total system access to report generators who were limited to
running predefined reports.
It was also possible for me to define multiple
reporting hierarchies so that user administrative and reporting rights were
limited to systems for which they had a need to see cost data. IT managers will
need to pay attention to how users are provisioned to ensure that they see only
data to which they are entitled. Although ad hoc reporting is possible in
vCenter Chargeback, automated reports are the mainstay of the system. I was
easily able to set up scheduled reports so that users could see how much they
were spending on virtual machine resources. Over a short amount of time,
vCenter Chargeback is a tool that will likely help IT and business managers
control costs and wring the most use out of their virtualized resources.