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As most virtual desktop infrastructure personnel know, Horizon 7 is out in general availability and much has been written about it. What hasn't been covered as much is Horizon for Linux. For those unaware, there is now improved support for Linux VDI desktops. Sure, Linux virtual desktop infrastructure may seem niche, but it's out there and it works.
Some of you may be wondering, why use Linux on virtual desktop infrastructure? The most obvious answer to that question is that Linux VDI is often free, though this isn't always the case -- most Linux VDI customers use paid versions of distributions, including Red Hat Enterprise Linux (RHEL) and SUSE.
Historically, a lot of powerful workstation-type workloads run on Linux with applications that do serious 3D rendering or some form of big compute.
So, who buys Horizon for Linux? The short answer is that a lot of vertical markets use Linux on VDIs and VMware Workstation. Sun Microsystems used to cover this territory almost exclusively, but after its merger with Oracle in 2009, software vendors and customers were left scrambling to make up the difference. Linux provides an easier path for most applications developers to migrate to rather than Windows.
Linux VDI under VMware
VMware saw Sun's loss as an opportunity, picking up the pieces for major customers looking for an easy way to simultaneously move away from Sun's legacy platforms and virtualize.
At the same time, migrating to virtual desktops seemed like a no-brainer, especially where computer-aided design, computer-aided manufacturing and other sensitive or proprietary information is used. It is easier to restrict undesired operations in a VM than in a physical box.
Although Linux on the desktop is pretty new, VMware has confirmed that it supports Linux VDI and aims to have a release every quarter that brings new functionality to the environment. Linux on VDI is no longer the poor relation in terms of support for VDI.
It is fair to say that the supported Linux VDI OS matrix is pretty small, with just a handful of supported distributions, including Ubuntu, RHEL, CentOS, SUSE and NeoKylin, a popular Chinese language distribution.
The beauty of Linux VDI under VMware is that its connection options are fully supported with the Blast protocol rather than some arcane X11 virtual network computing-type viewer. This means you can access the Linux desktop anywhere, so long as you can connect Blast to it, providing a modern, responsive experience regardless of the connection device.
The current release of Horizon for Linux, version 7.2, supports cloning from snapshots. This brings Linux manageability into the same realm as Windows in terms of basic functionality.
If you intend to work with Linux on Horizon, we need to talk licensing. There is a separate stockkeeping unit for those who wish to run just Linux on Horizon. Purchasing the Enterprise version will provide an administrator with the ability to run both Windows and Linux in the same environment.
Tips for running Linux on Horizon
First and foremost, in order to use Horizon for Linux you'll to have the latest version of Horizon, Horizon 7.2. This isn't just a suggestion, it's critical. Things in the Horizon for Linux space are moving so fast that there are major functionality additions even between sub point releases. For example, version 7.2 introduced full clone functionality.
You'll also need to be careful when setting up tools. Different distributions use either tools provided by VMware or open-vm-tools. Regardless of which you use, errors in the configuration process can cause a serious headache. I recommend consulting with the distribution vendor to see how they prefer tools to be configured.
Just as with Windows VDI environments, don't mix multiple Linux distributions in the same VDI pools. Doing so will cause issues and is not recommended -- and perhaps not even supported -- by VMware.
Be sure to correctly configure VM display settings, including video RAM; don't be afraid to refer to a support guide. You should also make certain that the domain name system (DNS) is working correctly. Don't leave your DNS to default to Dynamic Host Configuration Protocol. This is critical: If you want to integrate DNS into Active Directory (AD), you need to manually set your search domains in your DNS settings file. There is a known bug in the latest release of AD that will cause issues if not corrected before joining an AD domain. Both RHEL and CentOS require extra strings in VMX. RHEL has recommended settings for Linux on Horizon.
A lot of Linux distributions -- Ubuntu in particular -- come with services that provide negligible benefits or are just unnecessary in a VDI environment. You can remove items such as Compiz, Bluetooth, Postfix and mdmonitor. Removing these services will reclaim some system resources. For example, removing Compiz will significantly improve system CPU load on the host. Removal varies from distribution to distribution, but disabling the services is a straightforward task.
When adding new users, take care that their names don't clash with the names of existing users. This will cause all sorts of issues if you try to integrate with AD. This is one of the top causes of problems when setting up Horizon 7 on Linux.
When it comes to the management side, however, there is still some work to be done. Horizon for Linux doesn't support instant clone technologies. Building Linux VDI desktops is very much reliant on old-fashioned bash scripting or external tools that are brought in-house.
This will change as time goes on. VMware is working hard to make the Linux VDI functionally equivalent to its Windows counterparts.
Linux VDI desktops are a niche market
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