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Massive VMware Bug Shuts Systems Down
mattmarlowe writes "Imagine if Red Hat released a version of Linux, and after it was deployed, customers noticed that any processes with a start date of today would refuse to run? Well, that's what happened to VMware — a company that wants nearly all server applications running in virtual machines within a matter of years." Supposedly a fix will be available ... in 36 hours.
The only way to run a Windows domain controller in VMware is to tie its clock to the physical host's clock. And lots of things break if your domain controllers have the wrong time (Kerberos authentication, NTP across the Windows network, etc, etc). So changing the host clock would generally be a bad idea.
Simple...power. Right now our datacenter is strapped for power, and power isn't cheap. Neither is cooling. For 10U and 8000 watts I can install a fully loaded blade chassis with 128 CPU cores and 1 Terabyte of RAM, attach it to a SAN and run 150 VMs in it. Or I can install 150 rack and stack servers at taking up 4 racks and 75000 watts. Let me think here...
And while I'm thinking about it, let's also remember that using VMWare gives you options like DRS and VMotion that you don't get with physical hardware. Or you can replicate your SAN to another SAN at your DR site and have a VMWare cluster waiting there for recovery. Then instead of having to do a bunch of restores to bare metal hardware, you could potentially get your servers back up and running in minutes instead of hours.
There are many, many benefits to virtualization. If there weren't then people wouldn't have been using for decades in one form or another.
VMware is suggesting setting the system time backwards to work around their license manager problem. That's a desperation move. Not only will it mess up everything from Kerberos to CVS to "make", if you're running certain licensed software, in particular software licensed via FlexLM, that software will stop working. FlexLM will disable your licenses if the clock goes backwards by more than 24 hours. Now your expensive high-end software protected by FlexLM (Rational, Avid, Matlab, National Instruments, ANSYS, Cisco Unity, Clearcase, Nokia network management, etc.) will stop working. Setting the clock forward again may not re-enable it, either; there's tamper detection.
Also, if you have server/client licensing with FlexLM, or multiple license servers, and the clocks disagree significantly, FlexLM gets suspicious and turns licenses off.