An instant-clone desktop pool is an automated desktop pool. vCenter Server creates the desktop VMs based on the settings that you specify when you create the pool.
Similar to View Composer linked clones, an instant-clone desktop pool is based on a parent VM in vCenter Server. For instant-clone desktops, a parent VM is an internal VM that Horizon 7 creates and maintains, which is based on the parent VM in vCenter Server. You cannot modify this internal parent VM in vCenter Server. However, you can make changes to the parent VM in vCenter Server.
Instant clones share a virtual disk of a parent VM and therefore consume less storage than full VMs. In addition, instant clones share the memory of a parent VM. Instant clones are created using the vmFork technology. An instant-clone desktop pool has the following key characteristics:
- The provisioning of instant clones is significantly faster than View Composer linked clones.
- Instant clones are always created in a powered-on state, ready for users to connect to. Guest customization and joining the Active Directory domain are completed as part of the initial power-on workflow.
- When a user logs out, the desktop VM is deleted. New clones are created according to the provisioning policy, which can be on-demand or up-front.
- With the push-image operation, you can re-create the pool from any snapshot of any parent VM in vCenter Server. You can use a push image to roll out operating system and application patches.
- When clones are created, Horizon 7 selects a datastore to achieve the best distribution of the clones across the datastores. No manual rebalancing is necessary.
- View storage accelerator is automatically enabled.
- Transparent page sharing is automatically enabled.
- Instant clones require static port binding.
- Instant clones that use multiple vLAN networks require static port binding with fixed port allocation.
Because Horizon 7 can create instant clones quickly, you do not need to provision desktops up front or have many ready desktops. Compared with View Composer linked clones, instant clones can make the task of managing large desktop pools easier and also reduce the amount of hardware resources that is required.
Instant clones have the following compatibility requirements:
- vSphere 6.0 Update 1 or later.
- Virtual machine hardware version 11 or later.
As a best practice, configure distributed virtual switches in the vSphere environment.
In Horizon 7 version 7.2, instant clones have the following restrictions:
- Only floating user assignment is supported. Users are assigned random desktops from the pool.
- Instant-clone desktops cannot have persistent disks. Users can use network share or VMware App Volumes to store persistent user data. For more information about App Volumes, see https://www.vmware.com/products/appvolumes.
- Virtual Volumes and VAAI (vStorage APIs for Array Integration) native NFS snapshots are not supported.
- Sysprep and Quickprep are not available for desktop customization. Use ClonePrep, which is specifically designed for instant clones.
- Windows 8 or Windows 8.1 are not supported.
- IPv6 is not supported.
- Persona Management is not available.
- You cannot specify a minimum number of ready (provisioned) machines during instant-clone maintenance operations. This feature is not needed because the high speed of creating instant clones means that some desktops are always available even during maintenance operations.
The disk space reclamation feature that is available to View Composer linked clones is not needed because instant clones are refreshed when users log out. For instant clones, reclaiming unused disk space in a VM does not have a significant impact on storage consumption.