HW = HPQ DC7700 DuoCore 1.8GHz, 4 x 2GB RAM, 1 x 1TB SATA (AHCI) OS = CentOS-5.2 ix_64 (xen)
I am experimenting with Xen and with virtual machines in general for the first time. In consequence I have many questions. However, the one that I wish answered at the moment is simple:
Given a DVD containing the CentOS-5.2_Final (i386) distribution mounted at /media/CentOS_5.2_Final on Dom0, what argument do I pass to the "Install Media URL" argument of the "Create a new virtual system" wizard" to install the 32 bit version of CentOS-5.2 onto a vm called test-1?
I have tried things like:
/media/CentOS_5.2_Final /media/CentOS_5.2_Final/images /media/CentOS_5.2_Final/images/diskboot.img etc.
All attempts produce the same negative result. What URL is used to load the 32 bit OS from the dvd?
I am a digest subscriber so the favour of a direct copy of any reply to the list is appreciated.
Regards,
On Thu, October 9, 2008 09:47, James B. Byrne wrote:
HW = HPQ DC7700 DuoCore 1.8GHz, 4 x 2GB RAM, 1 x 1TB SATA (AHCI) OS = CentOS-5.2 ix_64 (xen)
I am experimenting with Xen and with virtual machines in general for the first time. In consequence I have many questions. However, the one that I wish answered at the moment is simple:
Given a DVD containing the CentOS-5.2_Final (i386) distribution mounted at /media/CentOS_5.2_Final on Dom0, what argument do I pass to the "Install Media URL" argument of the "Create a new virtual system" wizard" to install the 32 bit version of CentOS-5.2 onto a vm called test-1?
Well, apparently you cannot do this at all for a paravitualized guest OS. One is required to build an installation tree for the guest OS on the host dom0 and then use ftp or some similar protocol to access it, which requires configuring vsftpd or apache. And I also read that xen is now out of favour with RedHat and that KVM, which does not apparently support paravirtualization is the new kid on the block. Does this mean that I sould not bother with investigating xen?
In the meantime, since the link given in the VMM GUI help file for the example installation tree is defunct can some kind soul point me to a resource that describes how to build sucha thing from a CentOS-5.2 distro dvd?
Regards,
James B. Byrne wrote on Thu, 9 Oct 2008 10:31:09 -0400 (EDT):
In the meantime, since the link given in the VMM GUI help file for the example installation tree is defunct can some kind soul point me to a resource that describes how to build sucha thing from a CentOS-5.2 distro dvd?
You can just mount the DVD in the ftp server, you don't need to change anything. The directory with the Release-Notes is your installation root.
Kai
On Thu, October 9, 2008 10:31, James B. Byrne wrote:
In the meantime, since the link given in the VMM GUI help file for the example installation tree is defunct can some kind soul point me to a resource that describes how to build sucha thing from a CentOS-5.2 distro dvd?
From: Red Hat Enterprise Linux 5 Red Hat Enterprise Linux Installation Guide 28.9. Making the Installation Tree Available
The kickstart installation must access an installation tree. An installation tree is a copy of the binary Red Hat Enterprise Linux CD-ROMs with the same directory structure.
So: # cd /path/to/vm/os/install_tree # cp -pr /media/CentOS_5.2_Final ./
Thereafter the Install Media URL becomes: /path/to/vm/os/install_tree/CentOS_5.2_Final
On Thu, October 9, 2008 12:09, James B. Byrne wrote:
So: # cd /path/to/vm/os/install_tree # cp -pr /media/CentOS_5.2_Final ./
Thereafter the Install Media URL becomes: /path/to/vm/os/install_tree/CentOS_5.2_Final
Well, RH implementation of xen appears far less useful from an experimentation standpoint than I expected. From the Virtualization Guide:
With Red Hat Virtualization, 32-bit hosts runs only 32-bit paravirtual guests. 64-bit hosts runs only 64-bit paravirtual guests. And a 64-bit full virtualization host runs 32-bit, 32-bit PAE, or 64-bit guests. A 32-bit full virtualization host runs both PAE and non-PAE full virtualization guests.
So, on my test machine that supports only paravirtualization I can only run 64 bit versions of a supported paravirtualized guest OS. This limits me to essentially CentOS-4 and CentOS-5 ix_64. I was hoping to be able to run CentOS-5.2 i386 as a guest as there is no 64 bit Sun JRE that allows Firefox to run Java applets.
Oh well, this was just a trial to see what was involved with virtualization.
James B. Byrne wrote:
So, on my test machine that supports only paravirtualization I can only run 64 bit versions of a supported paravirtualized guest OS. This limits me to essentially CentOS-4 and CentOS-5 ix_64. I was hoping to be able to run CentOS-5.2 i386 as a guest as there is no 64 bit Sun JRE that allows Firefox to run Java applets.
Why not run it in fully virtualized mode instead of paravirtualized? Does your CPU lack the instruction set needed for full virtualization under Xen? I've never used Xen myself, followed it off and on and at least for me it's never looked interesting enough to pull me away from vmware. Now it looks like Red hat has woken up and seen it is a dead end too and is moving to KVM as you mentioned.
nate
On Thursday 09 October 2008 12:31, nate wrote:
Now it looks like Red hat has woken up and seen it is a dead end too and is moving to KVM as you mentioned.
where did you read this? I have just started with xen too but I don't want to be left hanging...
on 10-9-2008 10:19 AM sbeam spake the following:
On Thursday 09 October 2008 12:31, nate wrote:
Now it looks like Red hat has woken up and seen it is a dead end too and is moving to KVM as you mentioned.
where did you read this? I have just started with xen too but I don't want to be left hanging...
RedHat is moving to KVM because they bought it.
http://www.redhat.com/about/news/prarchive/2008/qumranet.html
Why give cash to a competitor if you can keep it in-house?
Scott Silva wrote:
RedHat is moving to KVM because they bought it.
http://www.redhat.com/about/news/prarchive/2008/qumranet.html
Why give cash to a competitor if you can keep it in-house?
Going back even further
http://searchservervirtualization.techtarget.com/news/article/0,289142,sid94...
With only 20,000 lines of code, KVM is simpler to develop and maintain than the 300,000-line Xen, he added.
"The best judge of the better hypervisor is the Linux community," Schnaider said. "And the momentum is shifting from Xen to KVM," with Red Hat and Ubuntu both announcing adoption of KVM, he said. [..] "Xen's been a great solution, but KVM offers more innovation and faster features," Cathrow said. "Technology moves forward, and KVM is the future."
nate
Nate wrote on Thu, 9 Oct 2008 11:36:13 -0700 (PDT):
ut KVM offers more innovation and faster features
I would hope that it actually offers just "faster", but AFAIK that is what it doesn't. AFAIK a PV CentOS 5 on Xen runs much better and faster than in KVM. Is that true? I've used KVM only once for a non-PV guest (old Suse System) and not with the kernel module.
Kai
Kai Schaetzl wrote:
I would hope that it actually offers just "faster", but AFAIK that is what it doesn't. AFAIK a PV CentOS 5 on Xen runs much better and faster than in KVM. Is that true? I've used KVM only once for a non-PV guest (old Suse System) and not with the kernel module.
I think KVM is still probably at least a year away from being really usable outside of specialized edge cases. In the meantime development will shift away from the free Xen causing it to mostly stagnate and onto KVM.
nate
James B. Byrne wrote on Thu, 9 Oct 2008 12:27:15 -0400 (EDT):
Oh well, this was just a trial to see what was involved with virtualization.
James, stop talking to yourself ;-) It's good to look at stock documentation, but it's not enough. Search this list archive for "xen" and have a look at the archives of centos-virt. You *can* run 32bit PV guests in 64bit CentOS. But you need Xen 3.2 for stability. You will find information about that and some necessary patches when you do the archive lookups I suggested.
Xen is really easy and reliably to use on CentOS once you know a bit about it.
Kai
I decided to come at this from a different angle and acquired a "Centrina???" Intel white-box 64 bit Core2 Duo system with Intel VT technology. This should give me "full virtualization" capability for Xen.
However, while the installer of the ix_64 package completes without problem (si long as the acpi=off switch is provided) I get an error when system first boots after the install followed by a halt
I see this message:
BIOS BUG No explicit IRQ entires. Using default mptable (tell hw vendor)
I get a second message relating to IRQ9 telling me to boot with irqpoll.
Does anyone here know what I need to do to get past this?
Regards,
On Thu, October 9, 2008 15:51, James B. Byrne wrote:
I decided to come at this from a different angle and acquired a "Centrina???" Intel white-box 64 bit Core2 Duo system with Intel VT technology. This should give me "full virtualization" capability for Xen.
However, while the installer of the ix_64 package completes without problem (si long as the acpi=off switch is provided) I get an error when system first boots after the install followed by a halt
I see this message:
BIOS BUG No explicit IRQ entires. Using default mptable (tell hw vendor)
The magical incantations to get this system to work were:
1. Discover that the MB is an Intel DQ35JO series. 2. Discover that the BIOS in a newly built system is 18 months out of date. 3. Get the most recent BIOS update from Intel.com as an ISO image. 4. Create a bootable CD-ROM from the BIOS ISO image. 5. Ensure that the BIOS drive settings emulate IDE (otherwise the CD-ROM is invisible to the system on the boot CD). 6. Boot from CD, wait until instructed and remove the CD (referred to as a floppy by the software), reboot and watch the system flash its BIOS. 7. Reset customized settings in the updated BIOS and select desired SATA drive type (AHCI in my case). 8. Install CentOS-5.2 using the command: linux pci=nommconf (per RH KBase) 9. Zoom, we're off and running.
Now, I have a test system that fully supports Intel VT technology and full-virtualization under Xen. However, having crossed that bridge I am now looking at whether KVM is where I should expend my limited time if, as it seems, that is where CentOS is heading.
Opinions?
Hello,
On Fri, Oct 10, 2008 at 10:08, James B. Byrne byrnejb@harte-lyne.ca wrote:
Now, I have a test system that fully supports Intel VT technology and full-virtualization under Xen. However, having crossed that bridge I am now looking at whether KVM is where I should expend my limited time if, as it seems, that is where CentOS is heading.
Opinions?
KVM will most certainly not be available and stable enough before RHEL6 and CentOS6. (Yes, I know you can get it from some repositories and make it work, but it seems to me that it's not perfect yet.)
Xen works right now and it does the job OK. The reasons why RH is moving out of it is not because it doesn't work, but it's because it's hard to upgrade the kernel with Xen supports. KVM is maintained by the kernel developers, so it has a much better chance to work well with newer kernels. The same is not true with Xen (at least right now.)
When RHEL6 and CentOS6 are out, if they support KVM as the preferred virtualization method, there will certainly be a good migration path from RHEL5+Xen to RHEL6+KVM (and the same for CentOS.)
So, in my opinion, you should stick with Xen right now and just worry about the migration to KVM when it's available, stable and supported. That's what I'm doing.
HTH, Filipe
James B. Byrne wrote on Thu, 9 Oct 2008 09:47:13 -0400 (EDT):
Given a DVD containing the CentOS-5.2_Final (i386) distribution mounted at /media/CentOS_5.2_Final on Dom0, what argument do I pass to the "Install Media URL" argument of the "Create a new virtual system" wizard" to install the 32 bit version of CentOS-5.2 onto a vm called test-1?
Is that what you mean the Virtual Machine Manager?
/media/CentOS_5.2_Final
All attempts produce the same negative result. What URL is used to load the 32 bit OS from the dvd?
You need a *URL*, that is not a URL! You can either use http or ftp. nfs may work as well, don't know.
There's a centos-virt list and there's a lot on virtualization on the wiki. Not sure if it would help you here, but it's worth reading!
Kai
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Filipe Brandenburger -
James B. Byrne -
Kai Schaetzl -
nate -
sbeam -
Scott Silva