One of the frequent critiques of vSphere is that the vCenter role and vSphere Client have been Windows-based through version 4. But that has changed in vSphere 5, says Rick Vanover.
With vSphere 5, administrators now have the option of running the vCenter server as a Linux appliance. This is a change from the Windows-based installations that have been the only option thus far along. The vSphere 5 vCenter Server Virtual Appliance or vCSA allows the vCenter Server to run on Linux. This virtual appliance is distributed as an OVF file from VMware and is based on SLES 11 for VMware. The database would use an embedded DB2 database and is suited for small vSphere environments (less than five ESXi hosts). For larger environments, a remote Oracle database connection is supported.
Using the vCSA will allow vSphere Client access on Windows as we have used before, but the vCSA won't offer all of the same features in this initial release as the Windows-based version of vCenter Server. The main limitations include lack of support for vCenter Linked mode, lack of IPv6 support, and lack of support for vCenter Heartbeat. The limitations are not deal breakers, and remember, this is a first release of this functionality; most other features are still supported with the vCSA. This includes using the Windows vSphere Client, patching capabilities, Active Directory authentication, and of course, it is supported as a virtual machine. Further, configuration of vSphere features such as HA, DRS, vMotion, and other key virtualization features are fully supported with the vCSA.
The fact that the vCSA is distributed via an OVF template makes it a quick way to deploy a virtual machine through the vSphere Client. A virtual appliance distributed as an OVF can also be deployed to an ESXi host before it is added to a vCenter Server. This can be of interest in the initial build of the environment, as the ESXi hosts would need to be deployed first and managed without a vCenter to then deploy the vCSA for the centralized management of the new environment.
Having the vCSA available as a Linux appliance is a contentious issue, in my opinion. If the environment is mostly a Windows environment then the vCSA may not be very attractive. During the blogger early access program, there was no mention of an eventual stoppage of the Windows version of vCenter. For Linux shops, it may be attractive to have vCenter installed on a Linux platform, though a virtual appliance is not the same as installing a Linux operating system directly.