[CentOS-virt] Now on to creation of disk images

Mon Jul 18 12:26:53 UTC 2011
Steve Campbell <campbell at cnpapers.com>

On 6/28/2011 10:50 AM, Ed Heron wrote:
> On Tue, 2011-06-28 at 09:30 -0400, Steve Campbell wrote:
>> Mr. Heron was so kind to make a suggestion that I should use disk images
>> to install VMs. Upon further thought, I kinda like the idea. So I
>> re-read the manual and google a little, and discover I still don't know
>> what should be in these disk images.
>> Should I copy the contents of the CDs to a file or what? I've got a test
>> server at the moment with Centos 5.5 and xen installed as the host OS,
>> but have just downloaded the 5.6 CD ISOs along with the  DVD ISO, so
>> I'll use 5.6 for my VMs. I've read about how I can create an image from
>> something that already exists.
>> Again, any clarity would be appreciated.
>    Just put the ISO's in /var/lib/xen/images and point at them.  If you
> didn't download the discs, you can rip them using:
> dd if=/dev/<optical device>  of=/var/lib/xen/images/<name of disc>
>    For example, if ripping the first 5.6 CD...
> dd if=/dev/hdc of=/var/lib/xen/images/CentOS-5.6-i386-d1.iso
> I generally rip a disc multiple times and then do a file compare to make
> sure I've got a reasonable chance of having an undamaged copy.
>    Keep in mind that it isn't as easy to change discs when you are using
> images on a paravirtual machine.
>    I still recommend setting up a local repository as a much better
> solution because it allows you to take a snapshot so multiple installs
> use the exact same versions of everything.

I moved the iso images to a folder under /var/lib/xen/images and 
selected it during an install for a new VM. I've run into a problem I've 
not yet seen before. The first iso is used just fine, but the second is 
"Not accessible", and nothing I can discover works.

So, should the ISOs be moved directly to the images folder instead of a 
folder below images? Does it matter whether I just copy the iso files 
(actually, I used scp) or do they need to  be run through dd?

Thanks for any help.