It seems quite a lot of folks wrote in while I was at VMworld. Normally I try to address these individually, or with a post if it would be beneficial. In this case, a commenter on one of my old VCP4 prep pages wrote to ask: “Why would you use a vApp over a Folder?” I’ll try to address that here:
What is a vApp?
A Google “I’m feeling lucky” for “VMware vApp” will bring you to the VMware page for “vSphere Application Services” or so.
A vApp, uses the OVF standard to hold information about your multi-tier application. That is, it will hold information about service levels, policies, security, as well as the components of the application (read: VM or VMs). Containing all of this information will allow the owner of the vApp to move between internal and external clouds* (Cloud definition here).
Why use a vApp?
As an application writer:
A vApp allows you to bundle your application with a specific set of definitions. Those could be as complex as multi-segmented virtual networking, or as simple as a startup order. Bundling these as a vApp allows you to take some of the complexity out of the setup process.
As an IT department:
Setting up vApps for parts of your infrastructure allows you to organize (like folders) VMs for your different groups and applications. Beyond organization however, like stated above, you can set service levels and policies (even if it’s nothing beyond startup order).
Ok, so why do any of that? After-all you’ve configured your networking and startup order in vSphere, or on your host directly. Well, one of the beauties of “The Cloud” is that you will be able to move your applications between your internal vSphere deployment and a providers “Cloud” or infrastructure. The vApp allows the policies and service levels you set to follow your application, in a standard format.
As an application consumer:
What this means to you as an application consumer depends. If means you will be able to purchase off the shelf applications that are ready to go. Spending less time and IT resources (or your resources if you’re a small shop), and more time delivering benefit.
I hope this clears up some information around what a vApp is and when/where you should use one. Questions, comments? Drop a line.
* Well there it is, I’ve tried to avoid saying cloud in posts, but alas, I suppose it will help my SEO rankings, however. Cloud Cloud Cloud!