A vService is a service that a solution provides to specific applications that run inside virtual machines and vApps. A solution can provide several types of vServices. Virtual machines or vApps can have dependencies on several types of vServices.
A vService is similar to a virtual hardware device upon which virtual machines and vApps can depend. Instead of providing a piece of virtual hardware, vServices typically provide access to a service across a network. By providing a vService, a solution can expose application-aware services to virtual machines and vApps. For example, a vService can provide a backup service or a logging service to virtual machines and vApps.
Virtual machines that use a vService have a vService dependency. If you mark a virtual machine as having a vService dependency, the virtual machine cannot power on unless you bind it to a provider of that vService.
If you deploy virtual machines by using Open Virtualization Format (OVF), you can specify in the OVF descriptor that the virtual machine depends on a vService. If you configure a virtual machine to have dependency on a vService, the solution that provides the vService receives notifications when specific events occur on that virtual machine. The vService can modify the OVF environment and OVF descriptor of the virtual machines and vApps that depend on it. With vServices, you can encode application-specific information in the OVF package about how a virtual machine or vApp interacts with a specific solution. You can also add solution-specific information to code running inside the guest operating system.
