cloner: don't fail to clone VM if nvram file doesn't exist

If a VM is defined and never started the nvram file might not exist and
in that case it's created by libvirt automatically on the first start.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1679018

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>

tests/clone-xml/nvram-missing-in.xml

@@ -0,0 +1,23 @@
+<domain type='kvm'>
+  <name>clone-orig</name>
+  <uuid>aaa3ae22-fed2-bfbd-ac02-3bea3bcfad82</uuid>
+  <memory>262144</memory>
+  <currentMemory>262144</currentMemory>
+  <vcpu>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='cdrom'/>
+    <loader readonly='yes' type='pflash'>/usr/share/ovmf/ovmf-efi.fd</loader>
+    <nvram>/nvram/clone-orig-missing_VARS.fd</nvram>
+  </os>
+  <features>
+    <acpi/>
+  </features>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-kvm</emulator>
+  </devices>
+</domain>

tests/clone-xml/nvram-missing-out.xml

@@ -0,0 +1,23 @@
+<domain type="kvm">
+  <name>clone-new</name>
+  <uuid>12345678-1234-1234-1234-123456789012</uuid>
+  <memory>262144</memory>
+  <currentMemory>262144</currentMemory>
+  <vcpu>1</vcpu>
+  <os>
+    <type arch="i686" machine="pc">hvm</type>
+    <boot dev="cdrom"/>
+    <loader readonly="yes" type="pflash">/usr/share/ovmf/ovmf-efi.fd</loader>
+    <nvram>/nvram/clone-new_VARS.fd</nvram>
+  </os>
+  <features>
+    <acpi/>
+  </features>
+  <clock offset="utc"/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu-kvm</emulator>
+  </devices>
+</domain>

tests/clonetest.py

@@ -162,6 +162,9 @@ class TestClone(unittest.TestCase):
     def testCloneNvramNewpool(self):
         self._clone("nvram-newpool")
 
+    def testCloneNvramMissing(self):
+        self._clone("nvram-missing")
+
     def testCloneGraphicsPassword(self):
         self._clone("graphics-password")
 

virtinst/cloner.py

@@ -346,16 +346,15 @@ class Cloner(object):
             self.clone_nvram = os.path.join(nvram_dir,
                                             "%s_VARS.fd" % self._clone_name)
 
+        old_nvram = DeviceDisk(self.conn)
+        old_nvram.path = self._guest.os.nvram
+
         nvram = DeviceDisk(self.conn)
         nvram.path = self.clone_nvram
-        if (not self.preserve_dest_disks and
-            nvram.wants_storage_creation()):
 
-            old_nvram = DeviceDisk(self.conn)
-            old_nvram.path = self._guest.os.nvram
-            if not old_nvram.get_vol_object():
-                raise RuntimeError(_("Path does not exist: %s") %
-                                     old_nvram.path)
+        if (not self.preserve_dest_disks and
+            nvram.wants_storage_creation() and
+            old_nvram.get_vol_object()):
 
             nvram_install = DeviceDisk.build_vol_install(
                     self.conn, os.path.basename(nvram.path),
@@ -365,8 +364,9 @@ class Cloner(object):
             nvram_install.reflink = self.reflink
             nvram.set_vol_install(nvram_install)
 
-        nvram.validate()
-        self._nvram_disk = nvram
+            nvram.validate()
+            self._nvram_disk = nvram
+
         self._guest.os.nvram = nvram.path