Open Virtuozzo (GPL/QPL) is an operating system-level server virtualization solution, built on Linux. Open Virtuozzo creates isolated, secure virtual private servers or virtual environments on a single physical server enabling better server utilization and ensuring that applications do not conflict. Each VPS performs and executes exactly like a stand-alone server; VPSs can be rebooted independently and have root access, users, IP addresses, memory, processes, files, applications, system libraries and configuration files.
Can this be compared to Solaris Zone concept?
I believe technology and some concepts are very similar, though implementation and user-level tools differs a lot.
Also, I think that inside every Solaris Zone you have Solaris, while in Open Virtuozzo you can have different Linux distros installed (the only common part is the kernel). This is probably not an Open Virtuozzo advantage per se, but the consequence of the fact that Solaris just don’t have different distros.
Is this like Xen?
http://www.cl.cam.ac.uk/Research/SRG/netos/xen/
If so, how does it compare?
Xen uses para-virtualization, while Open Virtuozzo is just virtualization (which gives you better performance).
The article at http://openvirtuozzo.org/documentation/tech/virtualization might be of help explaining the differences.
Yup, OS-level virtualisation should give higher overall throughput (if done right, (although for many workloads the difference is negligible anyhow). It’s also more convenient to manage since it’s easier to share data between the “guest” and “host” partitions (since the “guest” is basically an advanced chroot, you can copy files directly to/from it).
You do sacrifice some of the {performance, security} isolation of machine-level virtualisation, though, as well as the ability to run heterogeneous OSes, suspend to disk, do live migration, etc.
I think the two technologies are most flexibly used together: run OS images from different entities in machine-level VMs for high isolation, migration, etc. Then run multiple services in OS-level VMs for purposes of improved security / management.
I’m not an expert nor a Unix guy but I believe Xen requires that guest OS are modified to become “compatible”. Once they do, they will be “virtualized”. That should require a minor modification of code which doesn’t allow all OSes to run under Xen.
Xen requires OSes to be ported for performance and correctness reasons – virtualising x86 *fully* is really hard and has performance issues. With the new virtualisation-enhanced hardware that’s coming on the market soonish the modifications will no longer be necessary but they’ll help).
Virtuozzo is for running multiple “virtual servers” on one OS image, whereas Xen virtualises at a lower level to run multiple OS images on one host. You could run Virtuozzo (or similar products) in a Xen virtual machine – in fact I’d recommend this for people requiring highly flexible virtualisation.
It seems like Virtuozzo is something like Zones or Meiosys, but it’s not quite there. Like UML, it virtualizes userspaces on top of a common kernel. However, really it should be virtualizing process groups on top of a common userspace/kernel. That’s what Zones does, and that seems to be what virtualization customers want out of OS-level virtualization.
“Like UML, it virtualizes userspaces on top of a common kernel”
UML runs a kernel in userspace, virtualised systems do not run the same kernel as the host machine. There’s a big performance hit.
I think Virtuozzo is pretty like Zones / VServer: it’s a kernel mod to allow Linux to run multiple “virtual machines” by partitioning the process namespaces, filesystem, etc. I’ve not looked over it in great detail – does that sound right?
UML actually runs a whole kernel in userspace – they had to do some fairly tricky stuff to make this work but suffer a performance hit as a result.
From what I’ve seen of Meiosys, it appears to operate entirely by modifying / interposing shared libraries to make an application-level virtual machine, not touching the kernel. Is that right?
yes, it’s indeed pretty like Zones and VServer. But it’s being in development and production earlier than both Zones and VServer. 1-2 years I would say.
Vserver has been around a long time too: I certainly remember there being working code over 2 years ago but I’m not sure quite how long they worked on it before that.
Virtuozzo I originally heard of last year, although it was a full product by then. Interestingly, I think there used to be versions for BSD (and I thought they had at least some prototype development for Windows…) but these seem to have been dropped.
“Virtuozzo”… sounds from sicily?
what is missing in the open source version?
Forget about quality of code or licensing – if there’s something the OSS movement excels at is having a knack for choosing the silliest possible names for its projects. I thought ‘Mandriva’ was the epitome but boy, I was wrong. This takes the cake, by a mile. Maybe in the authors’ mind it was just a play on ‘virtuoso’, but as an Italian you can’t really get over how silly/mafia/hilarious/80’s comedy it sounds. Mad props.
Virtuozzo has been used for a long time by providers like Onyx.com, Rusonyx.ru. It’s like dedicated hosting. You have n% of resources and you never worry that any other host may steal from that.
As far as I know, Virtuozzo was written in Russia. No Sicilian mafia here 🙂
I wonder how does it sound in Russian… in Italian it sound strange and hilarious and originally I thought the author was Italian and wanted to use a funny (and nonsensical) name for his product!
🙂
The Virtuozzo kernel patch seems functionally similar to that the one of the vserver project:
(http://linux-vserver.org/)
I’ve been using the vserver patch for the last two years hosting twenty-so systems..
Maybe it provides better isolation than vserver?
Actually Virtuozzo supports both Linux and Windows Server 2003. The commercial version includes wizzards and GUI tools, and it’s been production ready for a while.
This software is very cool. I used to work for this company (SWSoft) several years ago, and I’m glad that they’re fully opening the code.
Is there any comparison between Virtuozzo and Vserver ?
Thanks