Parallels Virtuozzo Containers

[Robin Paulson]

does anyone have any experience of Parallels Virtuozzo Containers?

i believe it is a proprietary technology - is this correct?

how does it compare to the likes of xen and kvm, etc.?

[David Neil]

Robin,

Post by Robin Paulson
does anyone have any experience of Parallels Virtuozzo Containers?
i believe it is a proprietary technology - is this correct?
how does it compare to the likes of xen and kvm, etc.?

Parallels Virtuozzo is an operating system virtualisation tool (cf
platform virtualisation). Thus it runs a modified Linux as its base
system (Dom0 if you must - not correct terminology though), and is ONLY
able to run multiple 'virtual machines' of the same type of OpSys. So
you CANNOT start out with Linux and run a Windows client and a Ubuntu
client side-by-side, or similar.

However, because it does not have a hypervisor (per Xen, KVM, VM-Ware,
etc) it runs much more efficiently. As such, there have been a few web
hosting outfits attempting to make it work, and similar such
applications - today there's a parallel* 'Apache' conversation on
AuckLUG, which covers such ground.

Parallels is the name of the company (previously SWsoft). The
FOSS/community version is called OpenVZ. Interestingly, that web site
points to Wikipedia to answer your comparison question...

Which OpSys/distro do you want to use as your base?
What range of client/VM OpSys do you want to run?

Regards,
=dn
* sorry for choosing that word: the voices made me do it...


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[Dave Lane]

We run our hosting infrastructure with OpenVZ after migrating away from
Xen. We are running a base system of Debian Linux, with Ubuntu VZ
systems. We've seen substantial performance improvements (especially
with respect to I/O) over Xen. It's also seems much more stable.

Given that we're not interested in running OSs other than Linux, it's
not a big problem. The fact that the Debian kernels run happily on
Ubuntu systems is also very helpful. Debian has kernel-level support for
OpenVZ, whereas Ubuntu kernels only support KVM for virtualisation.

Cheers,

Dave

Post by David Neil
Parallels Virtuozzo is an operating system virtualisation tool (cf
platform virtualisation). Thus it runs a modified Linux as its base
system (Dom0 if you must - not correct terminology though), and is ONLY
able to run multiple 'virtual machines' of the same type of OpSys. So
you CANNOT start out with Linux and run a Windows client and a Ubuntu
client side-by-side, or similar.
However, because it does not have a hypervisor (per Xen, KVM, VM-Ware,
etc) it runs much more efficiently. As such, there have been a few web
hosting outfits attempting to make it work, and similar such
applications - today there's a parallel* 'Apache' conversation on
AuckLUG, which covers such ground.
Parallels is the name of the company (previously SWsoft). The
FOSS/community version is called OpenVZ. Interestingly, that web site
points to Wikipedia to answer your comparison question...
Which OpSys/distro do you want to use as your base?
What range of client/VM OpSys do you want to run?
Regards,
=dn
* sorry for choosing that word: the voices made me do it...
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[Phillip Hutchings]

Post by Robin Paulson
does anyone have any experience of Parallels Virtuozzo Containers?
i believe it is a proprietary technology - is this correct?
how does it compare to the likes of xen and kvm, etc.?

Some.

Yes.

It's more of a jail technology than a virtualisation technology. Both
Xen and KVM present an entire virtual machine to the guest operating
system, the guest doesn't have to know it's virtualised. By contrast,
Virtuozzo only virtualises the user-space, all machines share the
kernel but are isolated form each other, like a FreeBSD jail.

There are advantages and disadvantages to both. Virtuozzo has lower
overhead, but you're stuck with one OS. It all depends on what you're
trying to do.

[Cliff Pratt]

Post by Phillip Hutchings

Post by Robin Paulson
does anyone have any experience of Parallels Virtuozzo Containers?
i believe it is a proprietary technology - is this correct?
how does it compare to the likes of xen and kvm, etc.?

It's more of a jail technology than a virtualisation technology.
Both Xen and KVM present an entire virtual machine to the guest
operating system, the guest doesn't have to know it's virtualised. By
contrast, Virtuozzo only virtualises the user-space, all machines
share the kernel but are isolated form each other, like a FreeBSD
jail.

Like UML?

Cheers,

Cliff

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[Phillip Hutchings]

Post by Cliff Pratt

Post by Phillip Hutchings

Post by Robin Paulson
does anyone have any experience of Parallels Virtuozzo Containers?
i believe it is a proprietary technology - is this correct?
how does it compare to the likes of xen and kvm, etc.?

It's more of a jail technology than a virtualisation technology.
Both Xen and KVM present an entire virtual machine to the guest
operating system, the guest doesn't have to know it's virtualised. By
contrast, Virtuozzo only virtualises the user-space, all machines
share the kernel but are isolated form each other, like a FreeBSD
jail.

Like UML?

Not really. UML is kernel-level virtualisation. With UML every guest gets its own kernel with its own process space, own memory and own disk, the sysadmin of the host sees a UML process as a big blob.

Virtuozzo only virtualises user-space. The memory, disk and even process space is shared, it just appears as if it's private. The host admin can see every process inside the container as a process of the host kernel. The root filesystem of a virtual machine is just a directory in the host's filesystem.

Think of Virtuozzo more like chroot on steroids.
--
Phillip Hutchings
***@sitharus.com

[Nevyn]

Post by Phillip Hutchings

Post by Cliff Pratt
Like UML?

Not really. UML is kernel-level virtualisation. With UML every guest gets its own kernel with its own process space, own memory and own disk, the sysadmin of the host sees a UML process as a big blob.
Virtuozzo only virtualises user-space. The memory, disk and even process space is shared, it just appears as if it's private. The host admin can see every process inside the container as a process of the host kernel. The root filesystem of a virtual machine is just a directory in the host's filesystem.
Think of Virtuozzo more like chroot on steroids.
--
Phillip Hutchings

Just thought I'd add - UML = User Mode Linux.

I had always thought it was a jail as well. Whoops. Shows what I know.

Regards,
Nevyn
http://nevsramblings.blogspot.com/

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[Jaco van der Merwe]

Post by Phillip Hutchings
There are advantages and disadvantages to both. Virtuozzo has lower
overhead, but you're stuck with one OS. It all depends on what you're
trying to do.

like sharing kernel-based security vulnerabilities? (i.e. if the kernel is
compromised in a single userspace, all are popped)

(OTOH, it's only a single kernel that needs to be maintained)





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[Phillip Hutchings]

Post by Jaco van der Merwe

Post by Phillip Hutchings
There are advantages and disadvantages to both. Virtuozzo has lower
overhead, but you're stuck with one OS. It all depends on what you're
trying to do.

like sharing kernel-based security vulnerabilities? (i.e. if the kernel is
compromised in a single userspace, all are popped)
(OTOH, it's only a single kernel that needs to be maintained)

Yep, but a remote root will only get root inside the container. If you
break the jail you can access everything with little fuss, but with
full virtualisation it'll be harder to access data, though just as
easy to delete everything.

[Bruce Clement]

I'm pretty sure that this is the technology FDC Servers uses to
provide my virtual server. Assming that's so then everything David
says is correct to the best of my knowledge.

As a user, Virtuozzo is pretty much invisible, and it looks just like
a real remote server. I can do everything I want including full root
access.

Yes, I'm aware that I can't do some kernel based things such as
loading kernel modules, and I haven't a clue if I can mount file
systems, but they aren't not the kind of thing I've ever wanted to do
on remote servers so I don't miss them.

HTH

Bruce

Post by Robin Paulson
does anyone have any experience of Parallels Virtuozzo Containers?
i believe it is a proprietary technology - is this correct?
how does it compare to the likes of xen and kvm, etc.?
--
robin
http://creativespace.org.nz/
http://bumblepuppy.org/blog/
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Home:    http://www.clement.co.nz/
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"Before attempting to create something new, it is vital to have a good
appreciation of everything that already exists in this field." Mikhail
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[Brett Davidson]

I have some experience with Virtuozzo.

As the others say it's a jail-based system in effect.
As such, even though it presents itself as a "virtualised" server it
isn't which makes for one major caveat.
There is no swap space per VM. Makes sense as there is only one shared
kernel and you can only configure one swap "space" per kernel. (you can
have multiple files/partitions per space of course). That is not a major
problem except that you need to scope your memory requirements to
provide for the buffering effect that swapspace gives you.

Other than that it's quite an elegant solution for what it's intended for.

Brat.

Post by Bruce Clement
I'm pretty sure that this is the technology FDC Servers uses to
provide my virtual server. Assming that's so then everything David
says is correct to the best of my knowledge.
As a user, Virtuozzo is pretty much invisible, and it looks just like
a real remote server. I can do everything I want including full root
access.
Yes, I'm aware that I can't do some kernel based things such as
loading kernel modules, and I haven't a clue if I can mount file
systems, but they aren't not the kind of thing I've ever wanted to do
on remote servers so I don't miss them.
HTH
Bruce

Post by Robin Paulson
does anyone have any experience of Parallels Virtuozzo Containers?
i believe it is a proprietary technology - is this correct?
how does it compare to the likes of xen and kvm, etc.?
--
robin
http://creativespace.org.nz/
http://bumblepuppy.org/blog/
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Regards,

Brett Davidson
Systems Engineer
RHCE, CCNA, MCSE, SCSA, NZCE, TC(Electronics)

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