VMware rebootless upgrades are here!

It has finally happened – many years ago, when I worked at VMware, there were internal rumors of a rebootless upgrade being worked on since vSphere 5.0. And now, with the release of vSphere 6.7, you can upgrade the hypervisor without rebooting. What happens is the hypervisor will re-load, without having to reboot the entire host. This is much faster, particularly of an impact for sites with multiple hosts.

vSphere rebootless upgrade

VMware have released vSphere 6.7, which has a number of new features and capabilities, among which is the  integration of some features of VMware Update Manager (VUM) now being integrated into the HTML5 web client. With the normal VMware simplicity, you can enable Quick Boot with a check box, and then when VUM completes a hypervisor upgrade, VUM can leverage this feature to evacuate the host, restart the underlying ESXi software on the host without taking 10-45 minutes to preform a server POST and startup.

Why a vSphere reboot-less upgrade is good

I’ve written a previous article about how the reboot time of a server can be very slow (also published on the VMware site), and the time it takes a physical server to reboot can be significant. When you are used to the rapid time it takes a Virtual Machine to reboot, the VMware reboot-less upgrades are a significant time saver – in particular if you are managing a lights-out datacentre and all your communication to the host is remote.

Unfortunately my own test host is not compatible with vSphere 6.7, so I cannot test the feature – I don’t have a modern enough server. One thing I have not been able to try out is if you can manually perform a “Quickboot” of ESXi to resolve problems that don’t need a full server reboot. Please tell me in the comments below if you can test this.