One of the innovations that was released with vSphere 5.0 in 2011 was a Linux-based vCenter Server virtual appliance. This appliance, while it had potential, was limited in many ways with a maximum of five hosts, fifty VMs and a version of IBM’s DB2 as the database.

Fast forward two years, and the vCenter Appliance is starting to come into it’s own. The database has been updated to PostgreSQL and the host/guest count has been increased to 100 hosts and 3000 virtual machines. The web client has become the management interface of the future. It has gained a speed boost compared to previous versions, and all new features and support are now accessed through this interface.

Although the virtual appliance is easier to deploy and manage, there are some features that are in the Windows version that are not included with the appliance. Those features are:

• Oracle is the only supported external database. There is no support for IBM DB2 or Microsoft SQL Server.
• Linked-mode is not supported on the vCenter Server Appliance

If you require Microsoft SQL Server or linked-mode in your environment, you will need to use the Windows vCenter Server. Derek Seaman has a great series he’s running on configuring the Windows vCenter Server on his blog.

If you have an existing vSphere environment, you might be stuck with the Windows vCenter Server for the time being. There does not appear to be a supported migration path from the Windows vCenter Server to the appliance. The only option for implementing the appliance in an existing environment would be to start over. This may not be feasible if you have customized the permissions, alarms, or reporting for your environment, and this might hurt adoption of the appliance in some cases.

This series will cover the installation and configuration of the vCenter Server Appliance, and it will focus on the following topics:

• Installation of the appliance
• First power-on and initial setup
• Intial Configuration
• Single Sign-On Configuration
• Installation of new SSL Certificates
• Active Directory Integration
• Using the Web Interface
• Possibly some additional topics

Resources and Requirements

VMware has a suite of documentation available for download on their website. Two of the manuals that we will be drawing from are the vSphere Installation and Setup manual and the vCenter Server and Host Management manual. A couple of knowledgebase articles will also be referenced.

The list of hardware requirements is smaller than the Windows Server since there is less to set up – the appliance comes preconfigured with most of the hardware already configured. The appliance must be run on ESX/ESXi 4.0 or later.

The only thing that an administrator would need to change would be the amount of RAM allocated to the VM. That varies by inventory size, and those numbers are listed below.

• Very Small Inventory (less than 10 hosts and/or less than 100 VMs) – at least 4GB of RAM
• Small Inventory (10-100 hosts and/or 100-1000 VMs) – at least 8GB of RAM
• Medium Inventory (100-400 hosts and/or 1000-4000 VMs) – at least 16 GB of RAM
• Large Inventory (More than 400 hosts and/or more than 4000 VMs) – at least 24 GB of RAM

Note: The vCenter Server appliance officially supports 100 hosts and 3000 VMs. The numbers posted above are taken straight from page 19 of the vSphere Installation and Setup manual and may not, in some cases, represent officially supported configurations.

The appliance is configured to use 8GB of RAM when it is imported into your environment. I probably wouldn’t change that even if I had a very small deployment. There really isn’t a need to unless RAM is a constraint in your environment.

Although the vCenter Server Virtual Appliance does not require a Windows Server instance to run, Windows Server may be required for other components that might have otherwise been installed with vCenter Server.  The two components that come to mind immediately are the vCenter Update Manager (VUM), the ESXi equivalent to WSUS (ok…not a perfect analog, but good enough for now) and View Composer, a component of VDI environments that handle linked-clone VMs.

Use Cases for the Appliance

Is the vCenter appliance right for all environments? No. Like any piece of technology, it may not be the best fit for your environment or the skill sets of your administrators. But it may be right for a lot of environments.

So where could I use the vCenter Appliance? I have a couple of places where I would use it. This is my opinion, and I’d love to get your feedback in the comments.

1. New virtual environments
2. Smaller virtual environments (note – no migration path currently exists from Windows to Appliance)
3. Environments that want to reduce Windows license count as much as possible

The new host and VM limits should make it possible to use the appliance with virtual desktop deployments. I did get a very small (5 desktop) Horizon View 5.2 running on vSphere 5.5 in a test lab using the appliance. I hope to cover Horizon View on vSphere 5.5 in a later series.

There are also a few environments where the vCenter Appliance would not be a good fit.

1. Environments where PostgreSQL is not an approved database
2. Environments that must have an off-box database but do not have Oracle
3. Environments where Linked-Mode is required
4. Environments that exceed the number of supported hosts and/or VMs

Tune in Next Time…

In my next post, I will talk about installing the appliance in an ESXi environment and doing the initial configuration.