I just installed Centos 5.5 with the xen kernel on an older machine. It has Xeon processors and a 700 Mhz processor speed, so I realize I must use para-virtualized guests. Reading the Centos/RH Virtualization Guide gives examples of the process of installing guest hosts, but it only lists installing Windows as a fully-virtualized host.
Is that because they only showed those types of examples or is it that Windows hosts can't be para-virtualized?
Secondly, what's the normal what to install a Centos guest when it comes to defining the installation media (it lists HTTP, FTP, or NFS). This machine only has a CD drive, so I'm a little confused about the best way to handle this since the Centos installation now consists of 6 CDs. A brief explanation would be handy.
Thanks for any help and time offered. I'm sure there'll be more questions later.
Steve Campbell
--- On Wed, 6/16/10, Steve Campbell campbell@cnpapers.com wrote:
From: Steve Campbell campbell@cnpapers.com Subject: [CentOS-virt] new to xen - got questions, please To: centos-virt@centos.org Date: Wednesday, June 16, 2010, 9:11 AM I just installed Centos 5.5 with the xen kernel on an older machine. It has Xeon processors and a 700 Mhz processor speed, so I realize I must use para-virtualized guests. Reading the Centos/RH Virtualization Guide gives examples of the process of installing guest hosts, but it only lists installing Windows as a fully-virtualized host.
Is that because they only showed those types of examples or is it that Windows hosts can't be para-virtualized?
Secondly, what's the normal what to install a Centos guest when it comes to defining the installation media (it lists HTTP, FTP, or NFS). This machine only has a CD drive, so I'm a little confused about the best way to handle this since the Centos installation now consists of 6 CDs. A brief explanation would be handy.
You want to boot into a PV install. The initrd.img and vmlinuz shown in the filelist below are the tools for this included on the first CD in the set.
------------------ locate netboot boot files ----------- tlviewer@ga-p45:~> sudo mount /data2/kvm/CentOS-5.5-i386-bin-1of7.iso /mnt/iso -o loop tlviewer@ga-p45:~> ls -al /mnt/iso/images/xen/ total 9573 drwxr-xr-x 2 root root 2048 2010-04-29 17:29 . drwxr-xr-x 4 root root 2048 2010-04-29 17:29 .. -rw-r--r-- 2 root root 7552658 2010-04-29 17:23 initrd.img -r--r--r-- 1 root root 441 2010-04-29 17:33 TRANS.TBL -rw-r--r-- 2 root root 2244980 2010-04-29 17:23 vmlinuz ------------------ snip -----------
copy the above 2 to a local dir
#cat cent55.py ------------------- cent55.py --------- kernel = 'vmlinuz' ramdisk = 'initrd.img'
name = "cent55" uuid = "442db20d-7a82-409b-b8aa-a352c1fe127c" maxmem = 512 memory = 512 vcpus = 2 #bootloader = "/usr/bin/pygrub" #bootargs = "-q" on_poweroff = "destroy" on_reboot = "restart" on_crash = "destroy" vfb = [ "type=vnc,vncunused=1,keymap=en-us" ] disk = [ "phy:/dev/maxvm/cent55,xvda,w" ] vif = [ "bridge=br0" ] extra = " install=http://mirrors.kernel.org/centos/5.5/os/i386/ console=tty0 console=ttyS0,38400n8 console=xvc0" ----------------- unsnip --------------
#xm create -c cent55.py
this will start an http PV install. AFAIK the boot files are netboot only and won't allow access to your CD as ISO or otherwise.
Before firstboot, comment out the kernel/ramdisk lines and uncomment the 2 pygrub lines.
Windows guests can use drivers to work directly with the virtual-hardware devices that are presented to the guest. And since windows is acpi, etc. aware, with the right settings it works almost as if its paravirtualized.
When installing, for me its easiest to d/l and store the .iso file for whatever OS I have running, and boot directly from the iso to install. There's no need to mount the iso separately - xen and kvm can work with the file. And guests should be able to use your CD drive directly as well.
As for centos, I always use the network install iso, (which is tiny) and use that to install from the closest http mirror.
On Wed, 2010-06-16 at 12:11 -0400, Steve Campbell wrote:
I just installed Centos 5.5 with the xen kernel on an older machine. It has Xeon processors and a 700 Mhz processor speed, so I realize I must use para-virtualized guests. Reading the Centos/RH Virtualization Guide gives examples of the process of installing guest hosts, but it only lists installing Windows as a fully-virtualized host.
Is that because they only showed those types of examples or is it that Windows hosts can't be para-virtualized?
I'm not sure how far the para-virtualized drivers for MS Windows (XP?) have gotten. I would only install a MS Windows XP virtual machine as a fully virtualized guest, at this time. I haven't begun to work with Vista or 7.
If I were restricted to the older machine, I'd explore using VMWare. The bare metal version should be comparable to XEN performance, but the free version is restricted as far as the number (3?) of virtual machines that can be run. It'll virtualize MS Windows guests on older hardware.
Evaluate why you are using virtual machines... If this is an evaluation period, the older equipment is OK; Explore the alternatives. If this is a production machine, you'll be happier with a newer computer.
Secondly, what's the normal what to install a Centos guest when it comes to defining the installation media (it lists HTTP, FTP, or NFS). This machine only has a CD drive, so I'm a little confused about the best way to handle this since the Centos installation now consists of 6 CDs. A brief explanation would be handy.
Download the DVD and put it in /var/lib/xen/images/, set it as a virtual optical drive. The process is slightly different depending on whether you are creating the virtual machine using a xen config file, virt-install (command line) or virt-manager (gui).
If I were restricted to the older machine, I'd explore using VMWare. The bare metal version should be comparable to XEN performance, but the free version is restricted as far as the number (3?) of virtual machines that can be run. It'll virtualize MS Windows guests on older hardware.
The free ESXi can virtualize more then three guests. The limitations imposed on the free license revolve more around advanced capabilities within the suite. Things like vMotion (automatic guest migration between hosts), High Availability, etc are disabled.
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd...
Down at the bottom you'll find the edition comparatives.
On Wed, 2010-06-16 at 12:40 -0700, Drew wrote:
The free ESXi can virtualize more then three guests. The limitations imposed on the free license revolve more around advanced capabilities within the suite. Things like vMotion (automatic guest migration between hosts), High Availability, etc are disabled.
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd...
Down at the bottom you'll find the edition comparatives.
Thanks for that. Obviously, I am not entirely informed with respect to ESXi. I've used VMWare Server on Linux and MS Windows (XP, 2003) and, while it worked, I wasn't satisfied with the performance for a production environment. Due to my limited budget, I've been 'scared off' from setting up a ESXi testing environment, though it is still 'on my list of things to do'.
On Wed, Jun 16, 2010 at 12:40:48PM -0700, Drew wrote:
??If I were restricted to the older machine, I'd explore using VMWare. The bare metal version should be comparable to XEN performance, but the
The free ESXi can virtualize more then three guests. The limitations
I believe ESXi only works on 64bit machines with hardware VT. And it's very very limitted on the hardware it supports, but there's a nice community that has built out "oem" extensions. Be prepared for some hacking if you don't have a supported setup.
But once you've done that, it's pretty good.
I believe ESXi only works on 64bit machines with hardware VT.
Depends on the version.
ESXI 3.x will run on older 32bit only Intel Processors. I have it running on an old IBM x445 w/ 8 pre-64bit Xeon processors.
ESXi 4.x does require 64bit processors. I can't speak to whether it requires Intel's VT/VT-x or not as the ESXi 4 servers we're bringing in are all vmware certified.
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Steve Campbell