A flaw in the latest VMWare hypervisor update resulted in product licenses being declared invalid at midnight, with customers being rendered unable to run virtual machines (and as a result some applications) in their data centers. The license-recognition flaw was announced earlier today and a permanent patch is hoped for by tomorrow.The VMWare hypervisior flaw became apparent at the stroke of midnight when VMWare customers saw their ESX/ESXi 3.5 Update 2 licenses declared expired, shutting down their ability run (or relocate) virtual machines.

One suggested workaround was to reset system time/datestamps to August 10, an action that could raise as many issues as it solves and do so for many if not most businesses required by law and compliance regulations not to alter system clocks and stamps.

VMWare reports widespread outages as a result of the licensing flaw, and reports as well a scramble to prepare a patch.

When ready the patch will be on the VMWare download page, but no patch had shown up as of this posting. The problem updates themselves are now listed as "temporarily unavailable."

Good Slashdot dialogue on licensing and its annoyances here.

Take a look as well at this Paul Korzeniowski's very timely bMighty piece on the perils of locking your business into a single virtualization vendor.

And don't miss bMighty's 3-Part series on How To Virtualize A Server.

Good reading while you're waiting for VMWare to patch its problems and let your virtual machines get back to work.