From 418c08f5a4ef5c526fe172dbd3670bfffbf1b11d Mon Sep 17 00:00:00 2001
From: jbjohnso <jbjohnso@8638fb3e-16cb-4fca-ae20-7b5d299a9bcd>
Date: Thu, 26 Aug 2010 20:46:39 +0000
Subject: [PATCH] -check in some hints on how to do the clonevm stuff in kvm

git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@7269 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd
---
 xCAT-server/lib/xcat/plugins/kvm.pm | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/xCAT-server/lib/xcat/plugins/kvm.pm b/xCAT-server/lib/xcat/plugins/kvm.pm
index e45c49481..c8dd4fbe6 100644
--- a/xCAT-server/lib/xcat/plugins/kvm.pm
+++ b/xCAT-server/lib/xcat/plugins/kvm.pm
@@ -200,7 +200,22 @@ sub get_filepath_by_url { #at the end of the day, the libvirt storage api gives
         }
     }
     if ($create) { 
-        if ($create =~ /^clone=/) {
+        if ($create =~ /^clone=(.*)$/) {
+            my $src = $1;
+            my $fmt='raw';
+            if ($src =~ /\.qcow2$/) {
+                $fmt='qcow2';
+            }
+            my $vol = $poolobj->create_volume("<volume><name>".$desiredname."</name><target><format type='$format'/></target><capacity>100</capacity><backingStore><path>$src</path><format type='$fmt'/></backingStore></volume>");
+            #ok, this is simply hinting, not the real deal, so to speak
+            #  1)  sys::virt complains if capacity isn't defined.  We say '100', knowing full well it will be promptly ignored down the code.  This is aggravating
+            #      and warrants recheck with the RHEL6 stack
+            #  2) create_volume with backingStore is how we do the clone from master (i.e. a thin clone, a la qemu-img create)
+            #     note how backing store is full path, allowing cross-pool clones
+            #  3) clone_volume is the way to invoke qemu-img convert (i.e. to 'promote' and flatten a vm image to a standalone duplicate volume
+            #     incidentally, promote to master will be relatively expensive compared to the converse operation, as expected
+            #     will have to verify as it is investigated whether this can successfully cross pools (hope so)
+            #  4) qemu-img was so much more transparent and easy to figure out than this
         } else {
             my $vol = $poolobj->create_volume("<volume><name>".$desiredname."</name><target><format type='$format'/></target><capacity>".getUnits($create,"G",1)."</capacity><allocation>0</allocation></volume>");
             if ($vol) { return $vol->get_path(); }