Disclaimer – This is actually a re-post of a colleague’s Google+ post. I did not author this, nor am I claiming credit for this. Andrew Cathrow originally posted this on April 8. I just thought enough of it to repost it here. Additionally, while my preference/bias is clearly slanted towards KVM, VMware does have a solid product. They’re just not up front about their dependencies…
VMware has a lot of rather deceptive marketing around KVM and Linux. They have gone to great pains to hide their complete reliance on open source and Linux in particular. You may be saying to yourself “that was in the past but today with ESXi there is no more Linux because they removed the service console”.
You’d be wrong, actually you’d be really, really wrong.
It’s worth taking the time to download the 400MB tarfile that contains the open source code used in ESX5i – note this isn’t ESX with a service console it’s ESXi
So what will you find in there?
The first secret that so many people don’t know about is vmklinux. This is a subsystem that runs on ESXi and provides a compatibility layer to load Linux device drivers. Take a look at the drivers in the vmkdrivers-gpl/vmkdrivers/src_9/drivers directory of this archive. Then compare the VMware hardware compatibility list if you still don’t believe it. Yes, that’s right, VMware has a shim layer running in ESX so they can load Linux drivers in their proprietary kernel without worrying about that pesky old GPL license.
So that’s the driver layer – the hardware interface is derived from (GPL) Linux. Have a look through the rest of the tar file – I guarantee you’ll recognize some other familiar packages – gcc, glibc, gtk, libusb, ntfsprogs, e2fsprogs, sblim, open-iscsi, procps and many others.
Obviously it’s not wrong to use Open Source code, especially if you’re complying with the license, but next time you hear VMware’s marketing team claiming that KVM is an inferior hypervisor because it’s based on Linux then you might want to remind them that ESX wouldn’t exist without it either.