Re: [OSSTEST Nested PATCH v11 5/7] Add new script to customize nested test configuration

["Pang, LongtaoX" <longtaox.pang@intel.com>]

> -----Original Message-----
> From: Ian Jackson [mailto:Ian.Jackson@eu.citrix.com]
> Sent: Thursday, June 11, 2015 11:15 PM
> To: Pang, LongtaoX
> Cc: xen-devel@lists.xen.org; Ian.Campbell@citrix.com; wei.liu2@citrix.com; Hu,
> Robert
> Subject: RE: [OSSTEST Nested PATCH v11 5/7] Add new script to customize nested
> test configuration
> 
> Pang, LongtaoX writes ("RE: [OSSTEST Nested PATCH v11 5/7] Add new script to
> customize nested test configuration"):
> > [Ian Jackson [mailto:Ian.Jackson@eu.citrix.com]]
> 
> > > We would avoid having to mention /dev/xvdb if we created the VG in the
> > > host, before doing block-attach.  I'm not sure whether that's an
> > > improvement.
> >
> > I am sorry, I cannot get your point. Could you please make it more
> > clear? Thanks.
> 
> As you explain in the comment, you have to mention /dev/xvdb here even
> though after rebooting into Xen this will be /dev/sdb.
> 
> This wrinkle would become invisible if you did pvcreate and vgcreate
> in the L0 (before attach), rather than the L1 (after attach).
> Because, then none of your operations on L1 would not need to name the
> physical device.
> 
Thanks for your explanation.
For nested job, we will install L2 guest inside L1 reuse 'ts-debian-hvm-install' script.
But according to recent code design, inside L1 HVM guest, there is no vg group, so that we need to
create a vg group for L2 installation.
So, inside L0, we create storage lv(lvcreate -L ${guest_storage_lv_size}M -n $guest_storage_lv_name $vgname), 
attach this lv to L1. Then inside L1, using the attached disk to create a pv(pvcreate /dev/xvdb),
then create a vg(vgcreate ${l1_gn}-disk /dev/xvdb) base on the pv. Then, using this vg for installing L2.
I think '/dev/xvdb' is necessary when create vg inside L1, using command 'vgcreate ${l1_gn}-disk /dev/xvdb' .
Please correct me if I am wrong.

> Ian.