@scottalanmiller said:
@BBigford said:
@scottalanmiller said:
@BBigford said:
@scottalanmiller said:
@BBigford said:
Xen... XenServer... Xen server... Something I haven't looked into is the pricing. Xen is open source & free at the same time, that I have gathered. XenServer is something that Citrix has created, and charges for (open source, but not free... Red Hat in the same fashion. Open source, but not free). Xen server, any Xen server (can be open source and free, or can be XenServer... It's just a vague term). Anyone have any input? I'm always looking at new options for cost effective deployment in the right environment.
It's all open and all free. XenServer has no way to not be free because the license protects you. Citrix didn't create XenServer, it's built from Linux' Xen project and CentOS. Citrix just bundled it and sold support. And even that is in the past. Xen, XenServer are both part of the Linux Foundation, are both GPL and that means free.
Ok, I'm seeing it more clearly now. What Citrix was selling, was basically just support (bundled with the software of course, but they aren't technically selling the software, because they can't).
Almost right. They WERE selling the software, but it is also free. The GPL license that they are under allows EVERYONE to resell anything. So Xen, KVM, XenServer, CentOS, Ubuntu, etc. They are all under the GPL. You are allowed to give them away for free, the source is open. You are ALSO allowed to charge for them. You meaning EVERYONE. I can legally sell you Ubuntu, CentOS, XenServer, etc. So can Citrix. We are just... selling you something free. Does that make sense? I can charge you $1,000 for it, but you can turn around and give it away free or sell it yourself.
Okay, so Citrix didn't create XenServer (like taking Xen and making a distro specific to what they wanted to do with it). XenServer is essentially just a distro of Xen, that the Xen team created. Is that right? I'm trying to step back and see this clearly. If Xen is to Linux, I'm guessing XenServer is to Red Hat, or Ubuntu? It's just a distro of Xen? I've been looking at Xen wiki and The Xen Project. But I haven't found anything that says "here is the history of all things Xen so as not to confuse any parts of Xen itself."
Correct. Xen is the hypervisor and goes way back, it is nearly as old as VMware. Both of them predate hardware assistance on the CPU! Xen is the only one that has retained this heritage in its current design, it is the only hypervisor left that has a means of running without hardware assistance.
Xen is to Linux as XenServer is to RHEL. The CentOS version of XenServer is XCP. Identical, but without the Citrix branding. XenServer and XCP are a distro of Xen. Xen does nothing on its own, just like Linux.
Competing with XenServer / XCP are the native RHEL / CentOS, Ubuntu and Suse Xen stacks. You can do Xen from any of them (we were Suse/Xen for a long time) and this used to be popular because they were so much more up to date than XenServer. XS has fixed that for the most part and now that XenServer / XCP is a reference implementation of a Xen distro directly from the Xen team at the Linux Foundation there isn't much call for other versions.
Oracle VM is a head to head distro competitor with XenServer.
Ok, that makes a lot more sense. So if you want XenServer, you have to go to Citrix and pay for it, right? I did a proof of concept with XenServer in the past, and went to Citrix for the software & licensing. What I'm understanding, is that Citrix designed XenServer, and it is a paid for solution (like RHEL requires payment, and service is an optional/additional payment).
Thanks for taking the time to explain this by the way.