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Updated vCenter Server Appliance fuels speculation

The latest version of vCSA comes with hints that the services of the Windows installation version of vCenter Server may no longer be required.

When the vCenter Server Appliance debuted in 2011 in vSphere 5.0, end users loved the pre-packaged OVA that was simple to deploy and manage. As a bonus, it was built using a SUSE Linux OS which bypassed the requirement for a Windows license.

However, there were some minor problems. It didn't scale very well. It didn't have all the vCenter Server features. It had quite a large footprint and was a bit clunky to manage underneath; this was mainly due to the integrated IBM DB2 database that VMware packaged with the first iteration of the vCenter Server Appliance (vCSA). Thankfully, this was quickly replaced by a PostgreSQL DB in 5.0 update 1, which reduced the appliance footprint and also deployment times.

With each new version, vCSA became more stable and more complete. Previous limitations were addressed and configuration maximums slowly crept up for the embedded database deployment. With the release of vSphere 6.0 and vCenter Server 6.0, the appliance is now on-par with the installable Windows-based vCenter Server with regards to features and functionality.

Update addresses issues

There were a number of limitations with vCSA throughout version 5.x. The two key limitations, which prevented many end-users from deploying it into production, centered on the configuration maximums with the embedded DB and vCenter Server availability.

One of the advantages of having vCenter Server as an appliance is the luxury of not having an external database deployed. Given the appliance only supported Oracle databases, you didn't really want to deploy a full-blown Oracle environment just to scale your virtual estate. (Let's face it: Oracle isn't exactly cheap or easy to deploy.) The initial embedded database in 5.0/5.1 only scaled to five hosts and 50 VMs, which meant a large majority of customers immediately ruled out the appliance -- unless they had an external Oracle instance available. This limitation was addressed in vSphere 5.5 when the maximums increased to 100 hosts and 3,000 VMs -- a limit which VMware decided wouldn't be exceeded by 90% of deployments. With this increase, many administrators started to deploy the appliance as the production vCenter Server.

VCSA Configuration Maximum (using embedded DB)





ESXi Hosts per VC




Powered on VMs per VC




VMware increased the maximums again in vSphere 6.0 and moved from SQL Express, for the embedded database in the Windows installable vCenter Server, to the same database as the vCSA -- vFabric Postgres. One noticeable advantage of this change could mean easier migrations of data from the Windows vCenter to vCSA.

The lack of vCenter Heartbeat support and linked-mode support was another limitation in vCSA. These were key features given that large enterprises required a way to manage several instances of vCenter from a single client in linked mode and needed to ensure vCenter Server was always available with vCenter Heartbeat.

With the release of vSphere 6.0 and vCenter Server 6.0, the appliance is now on-par with the installable Windows-based vCenter Server with regards to features and functionality.

The lack of vCenter Heartbeat to improve the availability has now been addressed by the re-architecting of Fault Tolerance (FT) in vSphere 6.0 to support multi-vCPU VMs. Admins can consider using FT to protect the vCSA -- as long as the vCSA is limited to 4 vCPUs, so either the "tiny" or "small" environment deployments -- while also using vSphere HA to provide high availability functionality to protect against hardware failures.

The lack of linked mode has been addressed by the introduction of the Platform Services Controller (PSC) and its version of enhanced linked mode. PSC comprises single sign-on, certificate management, a license server and other management tools, which is easily replicated compared to previous versions of SSO. As a result of several architectural changes, PSCs can be linked and is supported on vCenter Server on Windows and vCenter Server Appliance. Enhanced linked mode connects multiple vCenter Servers -- either Windows or appliance -- by using one or more PSCs. It offers admins a single pane of glass for the vSphere domain. With enhanced linked mode, administrators can view and search across all linked vCenter Server systems, and replicate roles, permissions, licenses, policies and tags.

The recommended configuration when using enhanced linked mode is to use an external platform services controller

Close, but still some complications

There are however still some minor absences in vCSA:

  • Lack of vSphere CLI, which means you need to install the vCenter Management Appliance;
  • Lack of an integrated VMware Update Manager (VUM), which means you still have to deploy a Windows VM to install VUM;
  • Lack of an integrated View Composer, which means you still have to deploy a Windows VM to deploy Composer on;
  • No external database support for SQL Server, which means you're stuck with either the integrated DB or an external Oracle DB. However, the integrated database now provides greater connectivity maximums, so some question why you would want to deploy an external one; and
  • Inability to separate the individual roles of the vCenter Server (apart from the PSC), something you can do with a Windows install version. With the scalability of the vCSA would you need to separate the roles now?

Another clue in the form of an ISO image

Something else also caught my eye with the way the vCSA is now packaged with vCenter Server 6.0. VMware has moved away from distributing the vCSA as an OVA and decided to distribute it as an ISO image. Why would VMware do away with the OVA package?

Making an educated guess, this could mean they are planning to phase out the vSphere desktop client. If you aren't able to connect the client to your newly created ESXi host, then how would you go about deploying an OVA?

For example, in a freshly installed ESXi host, there's no easy way to manage it without either a vSphere client or a vCenter Server. Presently, you can't open a Web client to the host to manage it, so it makes sense to do away with the OVA deployment method. In its place, VMware has an ISO package with an installable run via a browser. That way, you can mount the installation package for the vCSA deployment without having to import the OVA via the vSphere desktop client. All you do is mount the ISO image onto your laptop, workstation or VM, then run the installation wizard via the setup Web page. During the installation process, all you require is the IP/hostname of the ESXi host you wish to deploy onto and the root credentials. The installer will then go off and deploy itself onto that host and set up vCenter Server.

VMware has tried to move administrators from vSphere Client to the Web Client with limited success over the years. Trying to manage vSphere using the vSphere Web Client in 5.1 and 5.5 was intolerable. However, with more than 100 enhancements to the Web client in vCenter Server 6.0, and huge improvements in usability and performance, VMware has come a long way in removing these barriers. While the Web client still uses Flash -- to the ire of many IT admins -- the dashboard, menu system and UI have been vastly re-architected to make it more user-friendly and, dare I say, actually usable.

The vSphere Web Client in vSphere 6.0 has an interface that isn't confusing and doesn't require minutes to log on or build the right-click menus. The only thing I can think of that requires the need of the vSphere desktop client is the VUM integration, which may appear in the next vSphere update.

Fling assists with the migration

And finally, VMware Labs recently released a new Fling that allows you to migrate from a Windows vCenter Server to a vCenter Server Appliance.

Previously, one of the problems was migrating data and settings from a Windows-based vCenter Server onto the new Linux-based vCenter Server Appliance. There wasn't an easy way to migrate the vCenter Server configurations across. The recommended migration path was to start over with a fresh install.

Having used the Fling, I can say that it works pretty well. The Fling migrates the vCenter database, roles, permissions, privileges, certificates and inventory service. It even migrates events and tasks lists, folders, vApp settings -- pretty much anything that's stored in the database. The only thing it didn't do was migrate the SSO configurations, which has to be set up manually, but is not too difficult to re-do.

However, there are quite a number of limitations. It's only a VMware Fling, so it has no official support but it's gained a lot of traction with the community since launch, so don't be surprised if VMware develops it into a full-fledged product.

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