7. Orchestration and Extension : 7.2 Cloud Provisioning with vFabric Application Director : 7.2.1 Simplifying vApp Template Management
   
7.2.1 Simplifying vApp Template Management
Catalog services can be constructed for each software component that is normally installed on virtual machines that are deployed to the vCloud environment. Consider a virtual machine as a collection of software packages and services running on a guest operating system. Most software components fit into a layered model where administrative duties might fall to different departments for maintaining software at each layer.
In the following figure, multiple layers of software and services define the characteristics of the virtual machine. By creating services for each component in the vFabric Application Director catalog, each department can maintain a service component in the catalog. This simplifies base virtual machine template creation and management process because the templates need to contain only the base operating system and appropriate patch level. All other services can be installed, configured, and started by vFabric Application Director.
Figure 39. Software Component Layers
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