Re: [Xen-users] Xen Configuration File Understanding

[Alexandre Kouznetsov <alk@xxxxxxxxxx>]

El 20/12/12 05:34, Patrick28 escribió:
> I created with lvm an logical value which is named /test-01/
> Now I want to install on this Logical Volume Centos6.3 from an ISO!
>
> First I don't know if it is possible to take in my Configuration this kernel
> ?
> kernel = "/usr/lib/xen/boot/hvmloader"
> builder = "hvm"
"kernel", from Xen's configuration file point of view, is the executable 
to load first, normally it has to be something that know how to talk to 
the underlaying hypervisor
In a similar way, when you configure your boot loader on a baremetal 
host, you have to pass control to a executable which knows how to talk 
to your hardware. It may be the boot sector of another partition where 
another boot loader resides, or directly a file containing a linux 
kernel for your system architecture.
In Xen's case, the control, within the Virtual Machine context, has to 
be passed to something that knows how to talk to the hypervisor. It may 
be a PV enabled Linux kernel. Or some special layer that could emulate a 
"normal" computer hardware for a unmodified OS, which is the case of 
hvmloader.
Normally, the configuration files for a PV guest and for a HVM guest are 
quite different, specially in the part that describe storage, booting 
and some fancy options to emulate video card and mouse.
pygrub allows you to extract the kernel image from the guest's block 
device, while the guest is still offline, and create the VM as it would 
do with "kernel" and "initrd" directives. Niels just described it in 
details, much better than I could.
> My Second question ist the disk-parameter. Now it looks so.
> disk =
> ['tap:aio:/dev/vg/test-01,sda,w','tap:aio:/mnt/disc/Centos6.3.iso,hdc:cdrom,r']
>
> Is hdc:cdrom korrect ? (For my ISO i created also an Logical Volume which I
> mounted to /mnt/disc/)
hdc:cdrom is correct.

Consider this syntax:
'file:/path/to/Centos6.3.iso,ioemu:hdc:cdrom,r'

Since the file containing your ISO is already a image of a block device, 
it can be exported directly to the VM. You could also copy it's content 
to a Logical Volume (low level copy, with dd or something), but normally 
there is no point to do that. A iso file is much easer to manage. On big 
installations you could even put all your ISOs on a NFS server and share 
them with all your hosts in ro mode.
It's very common to attach to a VM a cdrom using ISO file, and a system 
disk using a block device like a Logical Volume.
Greetings.

--
Alexandre Kouznetsov


_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxx
http://lists.xen.org/xen-users