The not-so-zero downtime VMware Tools Upgrade in vSphere 5.1

One of the cool new features of vSphere 5.1 is something that was announced as "Zero downtime VMware Tools upgrade". On my personal Top 5 list of vSphere 5.1 new features I even rated it #2, not without being skeptical about the zero downtime promise ...

A recent post by William Lam on the VMware vSphere Blog clarifies in what scenarios the zero downtime really applies. It is worth being fully read, but for readers who are always in a rush (or have a too short attention span ;-) I will wrap it up in a few bullet points:

• It works for Windows guests only, starting with Windows Vista
• If device drivers that are needed for booting (Display, vmscsi, pvscsi) are updated then a reboot is still required
• KB2015163 explains in detail if and when a reboot is still required after updating the Tools in a Windows VM

Please note: Given the fact that device drivers are rarely updated this is still a great progress compared to the pre-5.1 VMware Tools that would always require a reboot after an update!

How to use the latest VMware Tools with older vSphere versions

With vSphere 5.0 VMware made an important change regarding the compatibility and supportability of the VMware Tools: The Tools that come with vSphere 5.0 (and newer releases) can also be used with earlier vSphere releases (down to vSphere 4.0). For e.g. the latest VMware Tools of ESXi 5.1 the VMware Product Interoperability Matrix shows the following:

VMware Tools of ESXi 5.1 interoperability

Read more »

About the VMware Tools of ESXi 5.0 and why you should install them on vSphere 4.x

There is a rather new VMware KB article available that describes an interesting problem with the VMware Tools version of ESX(i) 4.1 Update 2: If the clock resolution of a Windows VM has been changed from the default then the VMware Tools service will continually consume 15% CPU performance (in a 1 vCPU VM, for 2 vCPU VMs it will be 7%, etc.).
We have seen this problem on few of our VMs, it looks like there are certain Windows applications around that change the clock resolution thus causing the problem. Detailed background information about the Windows clock resolution (and why it is not a good idea to change it) is available from Microsoft.

The resolution documented in the KB article is to downgrade the VMware Tools to an earlier version or - and this is probably surprising for most of us - to install the VMware Tools version of ESXi 5.0 instead.
This reminds us of the fact that VMware has changed their VMware Tools support policy with the introduction of vSphere 5.0: The VMware Product Interoperability Matrixes now include a selection for the VMware Tools, and it shows that the Tools of ESXi 5.0 are "interoperable" not only with ESXi 5.0 but also with ESX(i) 4.1 and even ESX(i) 4.0:

VMware Tools Interoperability Matrix

 ... whereas earlier versions were only interoperable with the corresponding ESX(i) version.

So, if you are still on vSphere version 4.1 or 4.0 and are planning to upgrade to vSphere 5 sooner or later then you can start deploying the VMware Tools of ESXi 5.0 now, and avoid the effort of future tools upgrades.
You can download the latest version of the ESXi 5.0 tools here at packages.vmware.com.

If you run a manual custom installation of the ESXi 5.0 tools in a Windows VM you will notice that there are some new components included:

VMware Tools 5.0 components default selection

The default selection of components (this is what you get when doing an automatic install or upgrade) is now more suitable for VMware ESXi than it was with earlier versions of the tools, but it still includes two components that are useful for VMware Workstation and completely useless when running ESXi: the Record/Replay Driver and the Audio Driver. Earlier versions of the Tools would also install the Shared Folders component by default, although it is also only useful with VMware Workstation.

A last hint: There is still another "feature" in the VMware Tools package for Windows that I personally find very annoying: Once you have installed the Tools you are by default not able to modify or repair the installation through the "Add or Remove Programs" control panel applet. To fix this find the GUID key for the VMware Tools package in the registry under
   HKLM\Software\Microsoft\Windows\CurrentVersion\Uninstall
and change the NoModify and NoRepair values there to 0.