LinuxQuestions.org
View the Most Wanted LQ Wiki articles.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Virtualization and Cloud
User Name
Password
Linux - Virtualization and Cloud This forum is for the discussion of all topics relating to Linux Virtualization and Linux Cloud platforms. Xen, KVM, OpenVZ, VirtualBox, VMware, Linux-VServer and all other Linux Virtualization platforms are welcome. OpenStack, CloudStack, ownCloud, Cloud Foundry, Eucalyptus, Nimbus, OpenNebula and all other Linux Cloud platforms are welcome. Note that questions relating solely to non-Linux OS's should be asked in the General forum.

Notices

Reply
 
Search this Thread
Old 03-28-2011, 12:44 PM   #1
Nemus
Member
 
Registered: Apr 2007
Distribution: Fedora/Ubuntu
Posts: 63

Rep: Reputation: 15
Unhappy Centos 5.5 Paravirtualization how to?


I am trying to setup a Paravirtualization debian ubuntu guest image using centos 5.5 the thing that I don't understand is the media url

How would I setup a media url ? or is there a public one I could use

thanks
 
Old 03-28-2011, 02:45 PM   #2
acid_kewpie
Moderator
 
Registered: Jun 2001
Location: UK
Distribution: Gentoo, RHEL, Fedora, Centos
Posts: 43,398

Rep: Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964
why would you want to do paravirtualisation? You should want from hyperthreading assuming your hardware supports it. What "media url" are you looking at? If you're booting from a network using kvm / qemu then this can be a simple nfs connection if you are using a network install, but moreover you have the option for an iso image, so you would want that for a first attempt.
 
Old 03-29-2011, 10:09 AM   #3
Nemus
Member
 
Registered: Apr 2007
Distribution: Fedora/Ubuntu
Posts: 63

Original Poster
Rep: Reputation: 15
PV kernel how to ?

so in Centos if you use the vitalization manager

go to page 39
http://www.centos.org/docs/5/html/5....ualization.pdf

it will ask for a media url

I am wondering if you can setup a ubuntu file system to install from a media url like centos so I can install a PV virtual machine.

From what I've been reading a Linux kernel that is "virtual aware" has better performance over a non "virtual aware system"

I am just curious about how I would create my own PV kernel and how I would create my own PV image.

like http://www.stacklet.com/
 
Old 03-29-2011, 12:50 PM   #4
Slax-Dude
Member
 
Registered: Mar 2006
Location: Valadares, Portugal
Distribution: Slackware
Posts: 254

Rep: Reputation: 72
Like the manual says, you have to download an .iso file for debian or ubuntu paravirtualized installation, mount it via loopback and extract the contents to a directory.
Now, make that directory available via nfs, http or ftp.
Point virtual manager to the url from your server.

That's about what it says on page 38 of the .pdf manual you provided.

Which part was confusing to you?
 
1 members found this post helpful.
Old 03-30-2011, 07:09 AM   #5
acid_kewpie
Moderator
 
Registered: Jun 2001
Location: UK
Distribution: Gentoo, RHEL, Fedora, Centos
Posts: 43,398

Rep: Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964
Again, you don't want paravirtualization if you can avoid it.
 
Old 03-30-2011, 11:22 AM   #6
Slax-Dude
Member
 
Registered: Mar 2006
Location: Valadares, Portugal
Distribution: Slackware
Posts: 254

Rep: Reputation: 72
Quote:
Originally Posted by acid_kewpie View Post
Again, you don't want paravirtualization if you can avoid it.
Care to explain why?
 
Old 03-30-2011, 03:09 PM   #7
acid_kewpie
Moderator
 
Registered: Jun 2001
Location: UK
Distribution: Gentoo, RHEL, Fedora, Centos
Posts: 43,398

Rep: Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964
Quote:
Originally Posted by Slax-Dude View Post
Care to explain why?
Because most modern cpus will support hyperthreading and so allow a better level of support from the hardware, rather than processing much of the work in software.
 
Old 03-31-2011, 02:21 AM   #8
Slax-Dude
Member
 
Registered: Mar 2006
Location: Valadares, Portugal
Distribution: Slackware
Posts: 254

Rep: Reputation: 72
Quote:
Originally Posted by acid_kewpie View Post
Because most modern cpus will support hyperthreading and so allow a better level of support from the hardware, rather than processing much of the work in software.
And how does hyperthreading help the OP isolating debian / ubuntu from his centos system?
He's right to look at paravirtualization, IMO.
 
Old 03-31-2011, 02:38 AM   #9
acid_kewpie
Moderator
 
Registered: Jun 2001
Location: UK
Distribution: Gentoo, RHEL, Fedora, Centos
Posts: 43,398

Rep: Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964
Quote:
Originally Posted by Slax-Dude View Post
And how does hyperthreading help the OP isolating debian / ubuntu from his centos system?
He's right to look at paravirtualization, IMO.
As I recall the installation process within libvirt-manager and qemu if hyperthreading is not enabled within a bios then you'll not have the option to run kvm vm's i.e. qemu-kvm only vm's without direct cpu access. This means that, as per the wikipedia article only a subset of specifically ported guest os's can run, and they require an abstracted software layer on the host to map the resources, but HT and association extensions allow direct cut through with the guest running directly against the hardware and not needing to be aware of it's vm status at all for those forms of operations.

Also given the style of question being asked I'm inclined to think that this level of subtlety is not actually required and the OP just wants to get a vm going. The doc originally referenced is about achieving improved virt with xen, which is no longer the preferred vm mechanism and kvm.
 
1 members found this post helpful.
Old 03-31-2011, 11:34 AM   #10
Nemus
Member
 
Registered: Apr 2007
Distribution: Fedora/Ubuntu
Posts: 63

Original Poster
Rep: Reputation: 15
so I downloaded an iso then mounted the iso to /var/www/html/distro made if available by http://x.x.x.x/distro/

and I get this error.

unable to complete install 'exceptions.ValueError Could not find an installable distribution at 'http://x.x.x.x/ubuntu/'
Traceback (most recent call last):
File "/usr/share/virt-manager/virtManager/create.py", line 724, in do_install
dom = guest.start_install(False, meter = meter)
File "/usr/lib/python2.4/site-packages/virtinst/Guest.py", line 539, in start_install
self._prepare_install(meter)
File "/usr/lib/python2.4/site-packages/virtinst/Guest.py", line 594, in _prepare_install
meter = meter)
File "/usr/lib/python2.4/site-packages/virtinst/DistroInstaller.py", line 245, in prepare
self._prepare_kernel_and_initrd(guest, distro, meter)
File "/usr/lib/python2.4/site-packages/virtinst/DistroInstaller.py", line 194, in _prepare_kernel_and_initrd
type=self.os_type, distro=distro)
File "/usr/lib/python2.4/site-packages/virtinst/OSDistro.py", line 156, in acquireKernel
scratchdir, type, distro)
File "/usr/lib/python2.4/site-packages/virtinst/OSDistro.py", line 136, in _acquireMedia
scratchdir=scratchdir, arch=arch)
File "/usr/lib/python2.4/site-packages/virtinst/OSDistro.py", line 100, in _storeForDistro
raise ValueError, _("Could not find an installable distribution at '%s'" %
ValueError: Could not find an installable distribution at 'http://x.x.x.x/ubuntu/'

Last edited by Nemus; 03-31-2011 at 11:41 AM.
 
Old 03-31-2011, 11:39 AM   #11
Nemus
Member
 
Registered: Apr 2007
Distribution: Fedora/Ubuntu
Posts: 63

Original Poster
Rep: Reputation: 15
HVM vs PV (Xen Full virtualization (HVM) Xen Paravirtualization (PV))

so its better to have Xen Full virtualization (HVM) than Xen Paravirtualization (PV)?

I am confused? from everything I've read PV should run better than HVM.

I am just experimenting, but would like to know what is the best to use for visualizing linux distros for optimal performance.

http://wiki.xensource.com/xenwiki/XenOverview

thanks
 
Old 03-31-2011, 12:19 PM   #12
acid_kewpie
Moderator
 
Registered: Jun 2001
Location: UK
Distribution: Gentoo, RHEL, Fedora, Centos
Posts: 43,398

Rep: Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964Reputation: 1964
centos 5.5 uses kvm as default, not Xen. Why are you referring to xen? Do you specifically want to use it?

As for performance, everything going through software interfaces can (surely??) only have an ultimately detrimental effect.
 
Old 04-01-2011, 12:33 PM   #13
Nemus
Member
 
Registered: Apr 2007
Distribution: Fedora/Ubuntu
Posts: 63

Original Poster
Rep: Reputation: 15
I am not sure exactly what the difference between xen and kvm is exactly but I've been using the

xm list
xm create

commands to view and console into vm's and I didn't install kvm during the install process so I am fairly certain I am using xen.

dose kvm have domU?

anyway from what I've been reading hvm uses more software to emulate the the true hardware while I know it does get a bost from the VT technology in the cpu. I am not sure if HVM has better performance than pv where a PV kernel passes its request directly to the xen kernel.
 
  


Reply

Tags
centos55, xen


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
xen paravirtualization and kernel numbers computeringman Linux - Virtualization and Cloud 2 11-02-2010 10:19 PM
LXer: Paravirtualization With Xen On CentOS 5.4 (x86_64) LXer Syndicated Linux News 0 12-15-2009 12:30 PM
LXer: Paravirtualization With Xen On CentOS 5.3 (x86_64) LXer Syndicated Linux News 0 05-17-2009 10:10 AM
Paravirtualization for dummies? Peufelon Linux - Desktop 2 06-14-2008 06:57 PM
paravirtualization hlinux Fedora 3 06-30-2007 12:28 PM


All times are GMT -5. The time now is 11:02 AM.

Main Menu
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
identi.ca: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration