I am finally starting to pull the plug on vmware 2 and want to start migrating to KVM, what I would like to know and I have searched but not found anything conclusive. Is it possible to run Vmware server 2 and KVM at the same time, I am running Centos 5.5 x64 on a 16 core 32g memory machine....the reason I would like to do this is that it would allow me to convert the vm's one at a time and do it in more of a phased approach, otherwise I may have to try to do it all at the same time....I dont have many VM's maybe 6 or 7 but would be nice if I could do them one at a time....Thanks in advance.... :)
I think that you can use the qemu without the kvm / kvm-(intel|amd) module. But i hardly think that VMware will still running with the KVM module loaded
On Mon, Aug 16, 2010 at 11:03 AM, compdoc compdoc@hotrodpc.com wrote:
At the same time on the same server? I don’t see how…
CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
On 16 August 2010 15:11, Danilo Nascimento danilo.nascimento.c@gmail.com wrote:
I think that you can use the qemu without the kvm / kvm-(intel|amd) module. But i hardly think that VMware will still running with the KVM module loaded
Only paravirtualised guests (so compatible linux) and not fully virtualised... that requires the kernel module. In addition I didn't think libvirt was compatible with kvm in non-hvm mode...
On Mon, Aug 16, 2010 at 03:41:37PM +0100, James Hogarth wrote:
On 16 August 2010 15:11, Danilo Nascimento danilo.nascimento.c@gmail.com wrote:
I think that you can use the qemu without the kvm / kvm-(intel|amd) module. But i hardly think that VMware will still running with the KVM module loaded
Only paravirtualised guests (so compatible linux) and not fully virtualised... that requires the kernel module. In addition I didn't think libvirt was compatible with kvm in non-hvm mode...
Uh.. are you mixing Xen and KVM now?
I think KVM *always* requires the kernel module, aka CPU support for hardware virtualization.
-- Pasi
Uh.. are you mixing Xen and KVM now?
I think KVM *always* requires the kernel module, aka CPU support for hardware virtualization.
-- Pasi
You might be right... having trouble googling something... but I thought that kvm without -enable-kvm (or with -no-kvm) and with -kernel, -append and -initrd specified could be used for a paravirtualized guest .... However that might just be fully emulated on qemu which might or might not help rather than paravirtualization...
My apologies if I err ^^ been a while since I had a system without available an vmx/svm interface on the CPU....
I know for a fact that libvirt doesn't support PV guests under KVM... virt-install (which uses libvirt) will refuse to try it etc.
I'll test it later this week to satisfy my curiosity ;)
James
On Tue, Aug 17, 2010 at 09:35:24AM +0100, James Hogarth wrote:
Uh.. are you mixing Xen and KVM now?
I think KVM *always* requires the kernel module, aka CPU support for hardware virtualization.
-- Pasi
You might be right... having trouble googling something... but I thought that kvm without -enable-kvm (or with -no-kvm) and with -kernel, -append and -initrd specified could be used for a paravirtualized guest .... However that might just be fully emulated on qemu which might or might not help rather than paravirtualization...
Without KVM Qemu runs everything on pure software, so it's still full virtualization, but damn slow.
My apologies if I err ^^ been a while since I had a system without available an vmx/svm interface on the CPU....
I know for a fact that libvirt doesn't support PV guests under KVM... virt-install (which uses libvirt) will refuse to try it etc.
Yeah, because PV guests are *Xen* guests. To run PV guests you need to be running Xen hypervisor.
I'll test it later this week to satisfy my curiosity ;)
"Xenner" is a separate tool that is able to run some Xen PV guests on KVM, but it's experimental and it's not developed anymore.
Xenner requires KVM, and thus CPU virtualization extensions.
Only way to run Xen PV guests on a hardware without CPU virtualization support is to actually use Xen hypervisor :)
-- Pasi
Thanks for the clarification.
On 17 Aug 2010 17:57, "Pasi Kärkkäinen" pasik@iki.fi wrote:
On Tue, Aug 17, 2010 at 09:35:24AM +0100, James Hogarth wrote:
Uh.. are you mixing Xen and KVM now?
I think KVM *always* requires the kernel module, aka CPU support for
hardware virtualization.
-- Pasi
You might be right... having trouble googling something... but I thought that kvm without -enable-kvm (or with -no-kvm) and with -kernel, -append and -initrd specified could be used for a paravirtualized guest .... However that might just be fully emulated on qemu which might or might not help rather than paravirtualization...
Without KVM Qemu runs everything on pure software, so it's still full virtualization, but damn slow.
My apologies if I err ^^ been a while since I had a system without available an vmx/svm interface on the CPU....
I know for a fact that libvirt doesn't support PV guests under KVM... virt-install (which uses libvirt) will refuse to try it etc.
Yeah, because PV guests are *Xen* guests. To run PV guests you need to be running Xen hypervisor.
I'll test it later this week to satisfy my curiosity ;)
"Xenner" is a separate tool that is able to run some Xen PV guests on KVM, but it's experimental and it's not developed anymore.
Xenner requires KVM, and thus CPU virtualization extensions.
Only way to run Xen PV guests on a hardware without CPU virtualization
support
is to actually use Xen hypervisor :)
-- Pasi
CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Just so you guys don't think I'm off my rocker...well not totally anyway ;) I did come across this post in fedora forum that got me to think it might work....
Currently, I have *VMware* *Server* 2.0 and *KVM* on the *same* headless machine with 4G mem, AMD 4400+. It's running for a small business, therefore, I don't mind the performance. However, *2* win2k advance servers on the *VMware* *server* 2.0, *2* win2k advance servers, a XP desktop and a m0n0wall firewall on the *KVM* are both running fantastically.
I'm a fedora fan, but the PC *server* which I set up is running on Debian Lenny (Proxmox, *you* guys might have heard).
I believe that *KVM* is better, though, I don't have any benchmark on them.
So was just wondering if anyone had tried to do this with centos....looks like I will give it a go, all of my clients are Linux.....centos of various flavors...I'll report back what I find out...
On Mon, Aug 16, 2010 at 9:03 AM, compdoc compdoc@hotrodpc.com wrote:
At the same time on the same server? I don’t see how…
CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
On 16 August 2010 15:55, Tom Bishop bishoptf@gmail.com wrote:
Just so you guys don't think I'm off my rocker...well not totally anyway ;) I did come across this post in fedora forum that got me to think it might work....
Currently, I have VMware Server 2.0 and KVM on the same headless machine with 4G mem, AMD 4400+. It's running for a small business, therefore, I don't mind the performance. However, 2 win2k advance servers on the VMware server 2.0, 2 win2k advance servers, a XP desktop and a m0n0wall firewall on the KVM are both running fantastically.
I'm a fedora fan, but the PC server which I set up is running on Debian Lenny (Proxmox, you guys might have heard).
I believe that KVM is better, though, I don't have any benchmark on them.
So was just wondering if anyone had tried to do this with centos....looks like I will give it a go, all of my clients are Linux.....centos of various flavors...I'll report back what I find out...
In theory it'll work if you make sure none of your vmware clients are trying to use VMI ... it's when multiple hypervisors try to take control of the hypervisor interface/instructions of a smv/vmx CPU that things get messy... without VMI the vmware guests will be fully virtualised and not trying to make use of the HVM extensions.... of course that could effect performance a bit but might not be noticeable over a short term....
I put together a simple conversion method I used at work to move from vmware to KVM - happy t opost the instructions if needed.
James
"I put together a simple conversion method I used at work to move from vmware to KVM - happy t opost the instructions if needed."
That would be good I have read several things but would be nice to see..... I'm not sure how much vmware server 2 makes use of the hardware extensions but thought I would give it a try and see what happens....
On Mon, Aug 16, 2010 at 10:05 AM, James Hogarth james.hogarth@gmail.comwrote:
On 16 August 2010 15:55, Tom Bishop bishoptf@gmail.com wrote:
Just so you guys don't think I'm off my rocker...well not totally anyway
;)
I did come across this post in fedora forum that got me to think it might work....
Currently, I have VMware Server 2.0 and KVM on the same headless machine with 4G mem, AMD 4400+. It's running for a small business, therefore, I don't mind the performance. However, 2 win2k advance servers on the
VMware
server 2.0, 2 win2k advance servers, a XP desktop and a m0n0wall firewall
on
the KVM are both running fantastically.
I'm a fedora fan, but the PC server which I set up is running on Debian Lenny (Proxmox, you guys might have heard).
I believe that KVM is better, though, I don't have any benchmark on them.
So was just wondering if anyone had tried to do this with centos....looks like I will give it a go, all of my clients are Linux.....centos of
various
flavors...I'll report back what I find out...
In theory it'll work if you make sure none of your vmware clients are trying to use VMI ... it's when multiple hypervisors try to take control of the hypervisor interface/instructions of a smv/vmx CPU that things get messy... without VMI the vmware guests will be fully virtualised and not trying to make use of the HVM extensions.... of course that could effect performance a bit but might not be noticeable over a short term....
I put together a simple conversion method I used at work to move from vmware to KVM - happy t opost the instructions if needed.
James _______________________________________________ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
On 16 August 2010 16:22, Tom Bishop bishoptf@gmail.com wrote:
"I put together a simple conversion method I used at work to move from vmware to KVM - happy t opost the instructions if needed."
That would be good I have read several things but would be nice to see..... I'm not sure how much vmware server 2 makes use of the hardware extensions but thought I would give it a try and see what happens....
No problem - I'm at home today but in the office tomorrow. I'll post my specific steps I documented then... but approximately from memory...
1. Make sure the vmware disk has no snapshots and is a 'full disk' 2. Convert the vmdk to a raw image (or qcow2... or even leave as vmdk dependant on your needs and performance issues) using qemu-img. 3. Construct an XML template for the new kvm guest and import it with virsh define. 4. Boot up from a CentOS live cd/dvd within the new kvm guest. 5. chroot into the disk within the guest. 6. remove vmware tools (if installed) 7. if using virtIO (advisable for performance) rebuild the initrd with the virtio modules: mkinitrd --with=virtio_blk --with=virtio_pci /boot/initrd.... <kernel_version> 8. change /boot/grub/device.map from /dev/sda to /dev/vda (assuming changing to virtio). 9. exit the chroot 10. reboot system from the disk instead of the live cd/dvd and troubleshoot/test
You shouldn't have to reinstall grub but you can do that from in a live CD via grub-install --root-directory=<mount_pount> /dev/vda if it goes weird...
That's pretty much it from off teh top of my head including the change from emulated (scsi|IDE) disks or (e1000|vmxnet) NICs etc over to virtio equivalents for performance... Centos 5.4 and up have the virtio modules natively for teh guest but they need an initrd with them in to boot off at first.... hmm come to think of it you could do that prior to shutting down and then skip the live CD/DVD step ... but then you wouldn't be able to start cleanly back into the vmware version rather than KVM if need be without a live CD/DVD for the grub device.map file ... otherwise it will just get unknown disk (I think?) errors...
James
-
compdoc -
Danilo Nascimento -
James Hogarth -
Pasi Kärkkäinen -
Tom Bishop