What is Instant Clones in VMware Horizon 7?

In March 2016, VMware’s end user computing team released the latest version of Horizon Suite, This version 7 has tons of new additional features and introduces us into a number of new products. With this version VMware has renamed its Horizon 6 with View to just Horizon Suite 7. VMware’s goal is simple to provide access to any application to any device from any place or it is called Digital Workspace. Digital Workspace is a combination of VMware Identity Manager another new concept along with Traditional Horizon VDI and Airwatch that manages the mobile devices. Instant clones, Blast Extreme Protocol are two important additions within the VDI space. With the help of Instant clones we will now be able to provision Just in Time Desktop, Literally just in matter of a second we can provision virtual desktops to users. Let us now take a deep dive on important enhancements.


Instant Clones

Instant clones as the name suggests clones an OS in a second. Instant clones also called as vmFork is a technology which was introduced from vSphere 6 uses Rapid in-memory cloning and Copy on Write (COW) features for instant cloning of a powered on VM. When ever there is a background task that wants to make changes to a shared information it firsts creates a separate copy of that information before making changes to it. A running parent VM is brought to a quiet state and then Forked. When a software or other work is split into two tasks, the resulting clones are then customized with unique MAC addresses, UUIDs, and other information and powered on. These clones share the disk and memory of the parent for Reads and are always ready for login instantly. After the clone is created, Writes are placed in delta disks. Both memory and disk are copy-on-write, so if a new clone modifies bits of its memory or disk, a separate copy is made for that virtual machine, thus preserving security and isolation between virtual machines. Customization process in instant clone uses a new ClonePrep technology which customizes OS without rebooting it. Therefore reducing the time to provision desktop. VMware’s extensive lab tests show results that although Instant clone have higher peak CPU utilization on vCenter it only lasts for very less time, therefore average load on CPU is reduced compared to Composer’s linked clone. The below image shows the different types loads on vCenter using Linked and Instant clones.



Some of important things that we must know before using Instant clones are :
1) Instant clones work only with vSphere 6.0 U1 or higher and VM Hardware version must be 11 and above
2) Instant clones is independent of View Composer and therefore no concept of Refresh, Recompose and Rebalance
3) Only Horizon Enterprise License has Instant clone technology
4) 3D rendering using latest vDGA is not supported on Instant clone
5) Windows 7 and Windows 10 are only supported for creation of Parent Image , No support for Windows 8.1
6) All Instant clones are non-persistent, With the help of App Volumes and User Environment Manger we can create persistent Instant clone
7) Every Host has its own ClonePrep Parent VM and these are always powered ON, We cannot power of these parent VM’s and cannot be migrated to any other Host
8) As user logs out of the Instant clone desktop gets deleted
8) Horizon Agent must be installed with instant clone feature and not composer feature, both features don’t work together
9) RDSH is not supported in this initial release

How does Instant clone work?


Master Image : Basically includes Operating systems ie Windows 7 or Windows 10 along with system applications such Anti virus , Office apps and Horizon agent etc
Snapshot : A quick snapshot is taken of the master image
Template : Every snapshot has its own template which is used for replica
Replica : The replica is a full clone of the Template that is thin provisioned.
Parent VM : Every ESXi Host will have their Parent VM. This parent VM is always powered on
Instant clone : Instant clone is provisioned in a second and instant clone desktop VM is deleted as soon as user logs out



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