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Citrix Machine Creation Services is a component of the XenDesktop virtual desktop infrastructure platform that IT administrators use to design and deliver virtual desktop images.
Using application programming interfaces, or APIs, from the underlying hypervisor, Machine Creation Services (MCS) configures, starts, stops and deletes virtual machines (VMs). MCS uses copies of a master VM, called linked clones, to provision virtual desktops. The clones include a differencing disk, an identity disk and optionally a personal vDisk, which is Citrix's name for a dedicated virtual disk that stores users' files, settings and other data.
Admins can create three types of virtual desktops with MCS:
Pooled-random desktops are nonpersistent virtual desktops assigned to users randomly every time they start a VDI session. These desktops erase any user-specific changes each time they reboot.
Pooled-static desktops are assigned to a specific user who is the only person able to use that desktop, but the user's personal data and settings do not carry over from session to session.
Dedicated desktops are assigned to specific users and include a personal vDisk so that any changes the users make to their desktops are saved.
To create a catalog of virtual desktop images, admins build a VM and select it as the master VM for a group of pooled desktops using the Citrix Studio management console. Machine Creation Services creates a snapshot of the master VM and a full copy of the snapshot, which it places in a storage repository to serve as the master image. MCS then adds the number of desktops admins want to create to Active Directory.
To update users' virtual desktops, admins can make changes to the master VM and then select the update option in Studio. For pooled-random and pooled-static desktops, MCS creates entirely new clones that replace the old ones the next time users boot up their desktops. MCS cannot update dedicated desktops without erasing all user customizations.