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VMware Tools is a collection of drivers and utilities that admins install inside the guest operating system of every VM in order to optimize performance and manageability of workloads running on vSphere infrastructure. We regularly hear customers ask if there is a way to avoid rebooting VMs after executing VMware Tools updates. Although there is a technique that can be used to postpone restarting the guest OS, the reality is that when replacing certain critical drivers on Windows, especially for storage devices, a reboot is necessary for the update to take effect.

The VMware Tools engineering group has been working hard to reduce the reboot requirements through various means and have delivered a breakthrough recently that really improves the situation for VMs running Windows Server 2016.

VMware is pleased to announce that the Paravirtual SCSI (pvscsi) storage driver is now available directly from Microsoft through Windows Update. This means that Windows Server 2016 VMs configured with a pvscsi adapter will automatically receive updates to that driver if Windows has Internet connectivity. To see if a new device driver has been downloaded from Windows Update, use the Device Manager utility and check the version number. If, for some reason, the device driver update has not been automatically downloaded, it is possible to manually initiate the update as shown in the demo below.  (I tweeted a sneak peek at this new capability recently and the response was amazing!)

Device Manager will also indicate if the OS requires a reboot:

While updating this Windows storage device driver still requires a guest OS reboot, this can happen in conjunction with other Windows patching operations. If patching, and rebooting, is done prior to updating VMware Tools, a subsequent reboot will not be required.

In the following demo, you can see a Windows Server 2016 VM configured with pvscsi storage, as well as a vmxnet3 network device. The VM has VMware Tools 10.2.0 initially installed, and the underlying host was recently updated to provide VMware Tools 10.3.0 installers. The VMware Tools update is initiated while the VM is under constant ping, and it completes with zero downtime to the workload!

When critical drivers can be updated in conjunction with other Windows patching, vSphere administrators benefit when subsequently updating VMware Tools because the driver will not require an update and a guest OS reboot will not be triggered.

NOTE: If you will be attending VMworld 2018 in Las Vegas or in Barcelona, you can learn much more about VMware Tools by attending breakout session VIN1972BU – Mastering the VMware Tools Lifecycle in Your VMware vSphere Data Center.

About the Author

Eric Gray

Eric Gray is a Principal Architect in Cloud Platform Technical Marketing, currently focused on vSphere host lifecycle management. He has been with VMware since 2005, and was a noncommissioned officer in the U.S. Army before migrating to Silicon Valley in 1996. Find him on Twitter: @eric_gray.