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

Mon Jul 18 14:17:12 UTC 2011
Kelvin Edmison <kelvin at kindsight.net>

On 11-07-18 8:26 AM, "Steve Campbell" <campbell at cnpapers.com> wrote:

> 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?

If you have SELinux enabled then it could be denying access to images in a
'non-standard' folder.  Try putting them directly in the images folder, or
alternatively, if you don't care about SELinux, setting SELinux to
Permissive or Disabled.