Xen Hacker Interviewed 95
Drawoc Suomynona writes "The Xen virtual monitor is a new generation virtualization software that enable running multiple OSes at the same time with unprecedented level of performances. Manuel Bouyer was recently interviewed about his work porting Xen to the NetBSD operating system. The interview touches on why some consider Xen to be so good, how hard it is to integrate such a software package into an OS, and more."
Re:In other news... (Score:5, Funny)
That's right, real men use BSD.
Re:In other news... (Score:1)
Re:In other news... (Score:3, Funny)
Re:Can someone explain (Score:5, Informative)
http://en.wikipedia.org/wiki/Xen_(virtual_machine
Re:Can someone explain (Score:5, Informative)
Also, I've seen this story in at least 3 places and I don't think it's right to say anyone ported Xen to NetBSD, NetBSD was updated (It's not exactly a "port") to take advantage of Xen features. It's possible that patches were sent to the Xen team to make things work more smoothly, but it's hardly porting.
VMWare emulates standard hardware (Score:2, Informative)
Re:VMWare emulates standard hardware (Score:2)
The problem is, you can't change the NT kernel, so no Windows.
However, with hard
Re:Can someone explain (Score:3, Informative)
And also, the Cambridge guys did come up
Re:Can someone explain (Score:3, Informative)
You're right, nobody ported Xen to NetBSD. That's not how Xen works. What happened was someone ported NetBSD to Xen. Instead of this new version of NetBSD accessing hardware, it asks Xen to do it. This required no modification of Xen, just modification of the NetBSD kernel to avoid accessing hardware directly. It's comparable with porting NetBSD to a new chip architecture.
Re:Can someone explain (Score:1)
Privileged guests (usually the domain0 guest) are an exeption to this because they do have direct access to the real hardware (a
Re:OS X ? (Score:3, Interesting)
Re:OS X ? (Score:5, Informative)
Re:OS X ? (Score:2)
And you believe those hacks why? (Score:2)
http://appleintelfaq.com/images/intel_vt_response
Re:And you believe those hacks why? (Score:2)
Heh, I'm curious whose shitty boards are you talking about. Are there any CoreDuo machines shipping now (or soon) that do have VT enabled?
Re:OS X ? (Score:1)
"The processors technically support it, but neither Dell nor intel have activated it yet. We are working to get the ecosystem ready before turning it on. Officially we are saying it will be enabled in 1H'06"
"Good news. Through the BIOS, you can turn VT on with the Inspiron
Re:OS X ? (Score:2)
Nope (Score:2)
Re:OS X ? (Score:2)
On hardware that supports it (new Intel and AMD chips do), Xen does not need changes to the guest operation system. So you might be able to run OS X and Windows at the same time.
Xen vs. jails (Score:4, Funny)
Also, glad to see the BSD section is at least still around. I can't seem to get it to show up on the Sections list, regardless of how I set it up.
Re:Xen vs. jails (Score:5, Informative)
Jails are lighter/faster but less secure (a kernel exploit in a jail will root the whole system).
Re:Xen vs. jails (Score:1)
Re: (Score:1)
Re:Xen vs. jails (Score:5, Informative)
In contrast, Xen can run multiple instances of different OS. That is, on one physical box, you could run Suse, Mandrake, Redhat, NetBSD, and even Windows. So Xen is closer to vmware than to jails.
Re:Xen vs. qemu? (Score:2)
Xen on Windows (Score:2, Interesting)
Can Xen run Linux apps on my Windows installation? I am currently using Cygwin for that, and it's working okay, but some of my favorite apps are being run through SSH from my linux box to make all this happen.
I do too much in Windows to even dual-boot the system... I'd spend as much time booting as I would working/playing.
Re:Xen on Windows (Score:2, Informative)
Re:Xen on Windows (Score:3, Informative)
Re:Xen on Windows (Score:1)
And thanks to you both for the CoLinux link. I'll check it out. Performance isn't really a problem as I have a pretty fast system and pretty un-demanding linux apps I like.
What about Virtualization? (Score:5, Informative)
Xen 3.0 on the newer Intel/AMD chips should be able to run Windows (or any other OS) without modification to the hosted OS.
Re:What about Virtualization? (Score:2, Insightful)
Re:What about Virtualization? (Score:1)
Between us, as others have pointed out - in the Xen world there is not really a "host" OS a-la VMware and friends but more of an OS which runs at Ring-0 and manages Xen. I don't think that the original questioner should care which OS is this as long as he can get both Windows and Linux running in parallel on his hardware, which will be possible with the new hardware I mentioned (allowing Windows to run under Xen and therefore allowing him to share the same hardware between Windows and Li
Re:What about Virtualization? (Score:1)
Re:Xen on Windows (Score:4, Informative)
Microsoft are planning to release their own Hypervisor next year, and you're right, their version will be built into the Windows Server product.e s+shape/2100-1016_3-5735876.html [com.com]
http://news.com.com/Microsoft+hypervisor+plan+tak
Re:Xen on Windows (Score:5, Informative)
Running OSes inside of Xen and running MS Windows inside of Linux are two completely different things. If you can run MS Windows inside of Linux, whether or not that Linux kernel is running inside of Xen probably won't matter, since for that to work at all you probably have to trap any protected instructions and emulate them. Whether the emulation is implemented using actual ring 0 instructions or Xen hypervisor calls should be irrelevant.
However, you _can_ run Windows inside Xen, and people have done so. It's difficult to do because you need to manage to get a Windows source license and build your own copy with the necessary modifications, but not impossible.
Re:Xen on Windows (Score:1)
Re:Xen on Windows (Score:4, Informative)
Virtual machines on XEN are called 'domains', and besides using virtual devices, they can also provide them.
Normally, domain 0 is responsible for providing almost all virtual devices (networking, disks etc). This may give the illusion that what runs in domain 0 is the host OS, but it is not, it is just another 'virtual machine', and while it is normal for domain 0 to do this, any domain running the proper kernel can provide devices to XEN.
Re:Xen on Windows (Score:5, Informative)
Xen layering and management allows you to do tons of stuff, I'm already doing SSI clusters on single machines. Xen + Win2k3 has been accomplished. This with CVIP / HA-LVS all running on one nic. Slice a high end p4 into a 6 + 1 (x 128) MB cluster of isolated servers. Its truly HA in a box, and very very simple.
The reason they call it a hypervisor is just that, its a step above a supervisory process. On VT enabled platforms (The new P4's / AMD's) you really start to see what xen can do without the bottlenecks of processor architecture.
Personally I think the ease of clustering is more important (and useful to the internet at large) than the ability to play with Windows stabalized under Linux. (I love saying that knowing its actually happened hehehehhe).
I can also say NetBSD does *very* well under xen.
Here's a really cool example config of how xen could slice up a high end dual xeon.
Assume
2 nics at 1000 MBPS, Connected to a gig-e switch. 100 MBPS x2 uplinks from 13 blended carriers. Basically, the average server you lease at any datacenter. Remember, you don't ever get to physically touch them. Xen is easy enough to install without needing local access.
You setup 2 smaller (maybe 256 MB each) netbsd firewalls , do some traffic shaping if you want. From there, you toss it over to an OpenSSI / Debian cluster running on the same machine.
Here's the really cool part. The bsd machines can talk to dom-0 and tell it when its time to drop nodes or add nodes, or make nodes bigger.
Need more servers? Simple . Xen them and load the ssi node image via pxe / etherboot.
Its very very easy then to setup the bridging needed to get a working cvip configuration and start weighting ports. So now you have 2 failover netbsd front end routers , failover LAMP and failover nics. Stick those SATA's in RAID1 and your only single point of faliure becomes your power supply or something going horribly wrong on domain 0. At the price it costs for those servers, you can afford 2 and pay under 500 bucks for the whole shebang if you lease them. Buying outright and co-locating is the best way. Or if your one of the fortunates with fiber coming into your own building
Now toss xen3 in there and you have yourself a win2k3 setup hosting your certificate authoirty, snaps, etc. bring it all into AD if you want. Its a networking "magic bag".
I'm just scratching the surface. These Guys [option-c.com] Have a really, really useful wiki, as well as some "unofficial" Debian install packages. Your average Linux geek could get it going quickly.
Keep your eyes on Xen. Its going to do good things for everyone - and its going to push commercial equals to
Windows is just one of the marvels folks. Look at the big picture. Some of us have been screaming Xen for a while now
Off the soapbox. Hope someone found this useful. It took an awful long time to type. Course would help if I wasn't eating messy food
Re:Xen on Windows (Score:3, Interesting)
I would think your bottlenecks would be constant context switches on your proc, cache misses on your virtual memory and seeks within your RAID (at the "hypervisor" level). No matter how good your top-level kernel delegates, it's still a level of indirection before control is pas
Re:Xen on Windows (Score:4, Informative)
You also have to keep in mind that most clusters are application specific.
With Xen and SSI you have two things that both do a very good job of
1 - Replace "dumb" round robin load balanced racks (it makes a very good load balancer)
2 - Isolating applications (nevermind the os we're talking about a single image)
I'm not going to go into number one because its obvious (or is to who I'm replying to).
Lets look closer at #2. I'd like to (for demonstration) use as an example the vast number of people using an open source application on their website powered by Apache, PHP and MySQL.
I'd also like to call attention to the fact that commonly those aren't the only 3 malloc()'ing hogs running on any given single server. In fact you'll find most public services running in one place. This means a mailer (exim for this example), Spam Assassin, Clam AV (if they care about their mailbox), MySQL, SMTP bandwidth logging generally using MySQL, SSH, most likely POP and IMAP. Eh, almost forgot DNS but bind is pretty small. Now they're all figting for cache, while trivial system processes live happily in dentry and watch the public ones choke to death. Xen helps you stop this.
Imagine 300 http sessions (lets say some chat program mandated session keep alives), now someone rolls in with a brute force spam attack. There goes exim, spam assassin and clam AV.
Pretty soon things just stop forking and said server needs its diaper changed. So what you described is also what most people have existing.
Now take a look at any 20 places selling co-located servers , or leasing them. You've got about $200 - $300 a month you can spend. Your site was a hobby and now its a kick in your wallet. You'll find a nice Dual Xeon 3.2 (even a 2.8 would work) and you can get a few nics and 4 GB registered RAM.
You can, then with Xen and OpenSSI solve your problem, isolate your services, make some of them highly available and you (can) do it on a single platform and increase its capacity drastically. We have a few things at play
1 - Xen's routing is very , very fast. That coupled with a sensible CVIP configuration can and will direct traffic as well as most medium line load balancers. I'm not talking about your $50k models that let you shape and direct down to the most miniscule trait of the session.. and I'm not talking about a cheapo. I'm also not calling out anything by brandname.. but I think you can relate for purposes of banter.
2 - You can't (and should not) run one of these from one physical ethernet device. While you don't need to give each node a seperate (real) nic, you really should split things up. By doing so you're freeing up kernel resources to do other things (like direct traffic avoiding I/O bottlenecks).
3 - You need to really play with your kernels. You really need to ensure you are taking advantage of your either (SATA) or preferably (SCSI) disks.
4 - You need to use sensible applications that interact nicely with your sql server, and (as you pointed out) have a very good understanding of Linux and its I/O. Be smart.. use flatfiles when you can (in other words plan your cluster).
5 - You can use xen in a more conventional setup too
So should Ebay fire one up today? No
But what I just typed is several options available to site owners who 6 months ago only had much more expensive options.
Re:Xen on Windows (Score:5, Informative)
VMWare Player... (Score:2)
Re:VMWare Player... (Score:4, Interesting)
It's called VMware Server and is in beta now.
However, it's not -entirely- free: VMware will charge for support, and there's no guarantee that updates and patches will be available for non-paying customers.
Re:VMWare Player... (Score:1)
It is, however, possible to run a 64bit guest OS on a 32bit host OS if the underlying CPU is 64bit, but if both the host OS and host CPU are 32bit, then the guest OS invariably can only be 32 bit.
Re:VMWare Player... (Score:2)
Migration (Score:3, Interesting)
And if a similar environment is not available when it is moved, what happens to the state of the user? Would the hardware in use when the state is saved have to be exactly alike on the target machine?
Also, is the information retained on the backup until the full migration is completed and then deleted, or is deleting the backup during the migration optional, leaving a "frozen" and "restorable" state on the server? Is that a security risk if the workstation is compromised?
Re:Migration (Score:2, Informative)
David
Re:Migration (Score:4, Interesting)
You will find processor differences though. Move from AMD to Intel, or drop SSE extensions or some such, and things will break.
Re:Migration (Score:2)
Re:Migration (Score:2)
The instant migrations are based on the vps being migrated between two host servers sharing the same storage system/SAN.
If you don't have a shared storage system holding your domU file system then you'd have to move that over as well (e.g. 15 minutes or so for a 4GB file system).
Oh and if you can't route the IPs betweens the two different hosts then you'd have to change the IPs to boot.
--
Xen-based VPS hosting [rimuhosting.com]
Re:Migration (Score:1)
Re:Migration (Score:2)
You can have a single backend SAN, and hookup more machines to it as you need more images... And you can hook up newer hardware and migrate the images live to the new machines without needing to reboot any of them.
Re:Migration (Score:1)
Re:*BSD is Dying (Score:1, Offtopic)
Heh, I hope IDC wasn't so bad as they were with predicting itanium sales. We're lucky that this time they're using a oracle [theregister.co.uk] to check their predictions, I hope they used it with BSD.
Re:*BSD is Dying (Score:1, Offtopic)
Now THIS is cool (Score:5, Interesting)
(Quote from Wikipedia)
Reminds of when I was watching the old Max Headroom show, and Max would shuffle himself off of one monitor onto a display on a portable "processing unit" and somebody would pick him up and carry him away.
What I want from virtualization (Score:2)
Re:What I want from virtualization (Score:3, Interesting)
Then what you want is Marathon [marathontechnologies.com] style lock-style execution. It's a terribly hard problem because you have to make all software run deterministically (timers and IO events on both machines have to occur in the *exact* same moments in execution).
Regards,
Anthony Liguori
Re:What I want from virtualization (Score:1)
Re:What I want from virtualization (Score:1)
Re:What I want from virtualization (Score:2)
Try VMWare ESX Server 3 (Score:2, Interesting)
Re:Solaris Zones... (Score:2)
Are here and they rock
And FreeBSD jails have been here forever and they rock.. They compare a lot better to Solaris zones then XEN does.
First difference: XEN runs virtual machines with possibly completely differet guest OSes, jails and zones run instances of their host OS as guests (often sharing the kernel).
Different purpose, different technology, tho with some incidental overlap (you could use both to create multiple 'virtual' environments on one piece of hardware)
Re:Solaris Zones... (Score:2)
Which would completely rock. I already love zfs in opensolaris, the ability to install a linux distro into a zone with xen would make me super happy.
Then I can get gentoo and solaris all in one. (don't argue about why I want Solaris to be the master domain, it is personal preference. mainly
Re:Solaris Zones... (Score:2)
Just having that will be enough to run Solaris and Linux at the same time, and other then a possible management interface I really wonder what zones have to do with this all, if you have any more information it would be appreciated.
Limerick (Score:1, Funny)
Sure his code is interestingly enough
It will fulfill our wettest dreams
Taking multitasking to the extremes
Filling our machines with marshmallow fluff
Linux? (Score:1)
Oh wait......
Facts about running Windows in Xen (Score:1)