tests: NoCloudKVMImage do not modify the original local cache image.

The NoCloudKVMImage.execute() would modify the image in /srv/citest
that meant that after the first time you ran a test, the image was
dirty.

The change here is to make the image operate on a qcow backed image.

Also modify Snapshot to then copy the qcow rather
than creating another chained qcow. The reason being that the image
might go away or change after the snapshot has been returned.

Also
 * drop use of 'override_templates' which was only relevant to LXD.
 * NoCloudKVM.create_image() returned an instance before
   now it has create_instance which creates an instance.
 * NoCloudKVMInstance has a 'disk' attribute separate from 'name'

1 files changed, 11 insertions, 6 deletions

diff --git a/tests/cloud_tests/snapshots/nocloudkvm.py b/tests/cloud_tests/snapshots/nocloudkvm.py
index 09998349..21e908da 100644
--- a/tests/cloud_tests/snapshots/nocloudkvm.py
+++ b/tests/cloud_tests/snapshots/nocloudkvm.py
@@ -2,6 +2,8 @@
 
 """Base NoCloud KVM snapshot."""
 import os
+import shutil
+import tempfile
 
 from tests.cloud_tests.snapshots import base
 
@@ -11,16 +13,19 @@ class NoCloudKVMSnapshot(base.Snapshot):
 
     platform_name = "nocloud-kvm"
 
-    def __init__(self, platform, properties, config, features,
-                 instance):
+    def __init__(self, platform, properties, config, features, image_path):
         """Set up snapshot.
 
         @param platform: platform object
         @param properties: image properties
         @param config: image config
         @param features: supported feature flags
+        @param image_path: image file to snapshot.
         """
-        self.instance = instance
+        self._workd = tempfile.mkdtemp(prefix='NoCloudKVMSnapshot')
+        snapshot = os.path.join(self._workd, 'snapshot')
+        shutil.copyfile(image_path, snapshot)
+        self._image_path = snapshot
 
         super(NoCloudKVMSnapshot, self).__init__(
             platform, properties, config, features)
@@ -40,9 +45,9 @@ class NoCloudKVMSnapshot(base.Snapshot):
                                 self.platform.config['public_key'])
         user_data = self.inject_ssh_key(user_data, key_file)
 
-        instance = self.platform.create_image(
+        instance = self.platform.create_instance(
             self.properties, self.config, self.features,
-            self.instance.name, image_desc=str(self), use_desc=use_desc,
+            self._image_path, image_desc=str(self), use_desc=use_desc,
             user_data=user_data, meta_data=meta_data)
 
         if start:
@@ -68,7 +73,7 @@ class NoCloudKVMSnapshot(base.Snapshot):
 
     def destroy(self):
         """Clean up snapshot data."""
-        self.instance.destroy()
+        shutil.rmtree(self._workd)
         super(NoCloudKVMSnapshot, self).destroy()
 
 # vi: ts=4 expandtab