Pascal's Wereld

My virtualization somethings, somewhats and the like.

VMware vCenter

Design Choice: vCenter Windows or vCenter Server appliance?

A question that is again popping up lately is whether customers must go for the vCenter Server Appliance (VCSA) or a Windows based vCenter system. Yes I have my favorite, but I will often go for the consultant answer: it depends. But on what does this depend? I will try and sum up some of the arguments to take in to account.

But first, what is this VCSA your talking about?

You may or may not know vCenter can be deployed in two ways, the commonly known vCenter installation on a Windows based host(s) or deploying vCenter as a appliance. The appliance is a 64-bit Linux based (SUSE Linux Enterprise for the distro interest) virtual machine with an embedded database (vPostgres) or the option to use an external Oracle database. The appliance has been around since it’s introduction with version 5.0, but has not been really production worthy since the 5.5 version. With the 5.5 version the vCSA supports managing 100 hosts and 3000 VM’s with the embedded database versus the 5 host and 50 VM’s with the previous version. The 5.5 limit for the external Oracle database is even higher (100 hosts and 10000 VM’s), but to be honest I haven’t seen that combination around.

VCSA

The appliance is build with the following vCenter services: vCenter services (vCenter, Inventory, SSO, Web Client) and services such as syslog collector, dump collector, AutoDeploy (and capable of doing DHCP/TFTP).

vCSA services

What are the arguments to consider?

  •  For organizations that are having a DBMS install base of MSSQL there is currently no support of using this in combination with the vCSA where the Windows based happily works with MSSQL (via ODBC DSN). If there is no experience, no business investment or no DBA’s wanting to manage an additional DB flavor you can stop right here (or wait when a next version of VCSA will hopefully support MSSQL as an external database).
  • Windows vs Linux install base and license. You got your Windows based organizations and you got your Linux based organizations. More often they are mixed. Got Windows data center licenses sorted out for your organization, another Windows VM is often not an issue. Need to save some licensing or just don’t want to invest in new, VCSA will probably be more of your taste. Beware that you can’t install Update Manager on VCSA, this still needs to be set up on a Windows host which can be an existing. Same goes for your trusty toolset, PowerCLI needs Windows PowerShell, RVTools need .Net. These tools can be easily put on a management server or admin workstation (where the toolset are supposed to be on the first place), they connect to VCSA just as vCenter on Windows. Need remote CLI? Added by deploying the vSphere Management Assistant (vMA) appliance. For Windows only based IT departments a knowledge investment is needed to support Linux based appliances.
  • vCenter Orchestrator. Windows vCenter installers installs vCenter Orchestrator on your Windows system or you can use the Windows installer to install Orchestrator on another designated Windows server. vCenter Orchestrator is not installed on the VCSA, but there is the vCenter Orchestrator appliance you can deploy next to it.
  • Linked mode. Want a single management plane, or in other definition a Single Pane of Glass, for multiple vCenter instances linked mode is required. VCSA does not support Linked mode where vCenter on Windows does. There is an other option, leveraging the built-in SSO Replication by joining all (or some you want to share) SSO instances under a common domain. A benefit next to the automatic synchronization, is that you will be able to see the inventory of all SSO instances from whatever Web client.
  • Experience with appliances. I think appliances add simplicity for deployment of the vCenter systems, but can be a hassle to (re)configure and for example do database back-up dumps when you don’t have any experience with Linux. Don’t worry, VCSA has an admin Web interface or the vSphere Web client for configuration tasks and when you need the console commands are documented. The procedures are on Documentation Center, Knowledge Base and widely blogged about in the community. Go ahead and learn appliances as there are a lot of good ones.
  • Monitoring/Back-up. Monitoring of vCenter server services and system parameters. If you use a Windows based or agent type of monitoring, the Windows based monitoring does not work for a Linux appliance. Check if your monitoring solution supports Linux. Same goes with thinking about your back-up strategy and how to back-up the VCSA.
  • Physical vCenter. When there are reasons to install the management of your virtual infrastructure on a physical server outside the virtual infrastructure, than Windows vCenter is the only option. VCSA is a virtual appliance which needs to be deployed on virtual environment. Depending on the requirements, you could also go with an VCSA deployment in an other vSphere cluster than the one vCenter is managing.
  • IPv6. IPv6 is not supported on the VCSA and is supported on Windows. If you happen to use IP addresses in the vCenter configuration or connecting to vCenter these are IPv4 only. To connect to vCenter system in an IPv6 environment you must use the fully qualified domain name (FQDN) or host name of the vCenter Server. FQDN is preferred to be used in any case.
  • vCenter Server Heartbeat. Use this solution to protect your vCenters, you cannot use this with the VCSA. But on the other hand, you should be working on a replacement solution (you have some time) as VMware announced EOA of all vCenter Server Heartbeat versions. See details here: http://www.vmware.com/nl/products/vcenter-server-heartbeat. Leveraging vSphere HA instead for example.

Note: These arguments are not ordered by importance, that’s is up to the organization in question.

And what do you think?

I have a favorite, but do keep in mind that there is no one size fit’s all. I happen to like the appliance way of deployment, simplicity at your fingertips and no abuse from Windows admins logging on and hogging the vCenter resources (sizing) with OS / RDS footprint. Or worst destroying to system with all those I needs this and this tool for my work.

Yes you need Windows for Update Manager, which can be combined with other update management tools. And yes you need your Windows based tool set somewhere, are those supposed to be on the vCenter server in the first place?
When a design decision is made to use the Windows based vCenter, please use it as an infrastructure server. Don’t abuse it as an administrator playground (aka RDS server, aka steppingstone, aka PowerCLI test heaven). I like to remove the GUI aka use core when Windows is the design choice (PowerCLI Get-WindowsFeature *gui* | Uninstall-WindowsFeature –Restart). From Windows version 2012 switching from GUI to core does not require a reboot.

What do you think? I’m interested in your views. Let me know in the comments.

Sources: vmware.com, microsoft.com

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1 Comment

  1. I like the VCSA more than the Windows install. My infrastructures usually have an windows AD server, VCSA with embedded DB, Windows VUM server and another management server with all my tools.

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