Fix QA tests related to OS image

If QA storage is enabled, fetch OS images and use them to test
instance reinstalls.  Otherwise, just skip the two tests regarding OS
images.
Signed-off-by: Jose A. Lopes <jabolopes@google.com>
Reviewed-by: Hrvoje Ribicic <riba@google.com>

qa/qa_instance.py

@@ -340,73 +340,40 @@ def TestInstanceReinstall(instance):
     print qa_utils.FormatInfo("Test not supported for diskless instances")
     return
 
-  master = qa_config.GetMasterNode()
-
-  AssertCommand(["gnt-backup", "export", "-n", master.primary, instance.name])
-
-  instance_info = GetInstanceInfo(instance.name)
-  disk0 = None
-
-  for volume in instance_info["volumes"]:
-    if "disk0" in volume:
-      i = volume.find("/")
-      if i >= 0:
-        disk0_id = volume[(i + 1):]
-      else:
-        disk0_id = volume
+  qa_storage = qa_config.get("qa-storage")
 
-      disk0_path = "/srv/ganeti/export/%s/%s.snap" % (instance.name, disk0_id)
-
-      try:
-        AssertCommand(["stat", disk0_path])
-        disk0 = disk0_path
-        break
-      except qa_error.Error:
-        pass
-
-  if disk0 is None:
-    raise qa_error.Error("Could not determine exported disk for instance '%s'" %
-                         instance.name)
-
-  image = qa_utils.BackupFile(master.primary, disk0)
+  if qa_storage is None:
+    print qa_utils.FormatInfo("Test not supported because the additional QA"
+                              " storage is not available")
+  else:
+    # Reinstall with OS image from QA storage
+    url = "%s/busybox.img" % qa_storage
+    AssertCommand(["gnt-instance", "reinstall",
+                   "--os-parameters", "os-image=" + url,
+                   "-f", instance.name])
 
-  AssertCommand(["gnt-instance", "reinstall",
-                 "--os-parameters", "os-image=" + image,
-                 "-f", instance.name])
+    # Reinstall with OS image as local file on the node
+    pnode = _GetInstanceField(instance.name, "pnode")
 
-  try:
-    port = 8000
-
-    while True:
-      cmd = "( cd /srv/ganeti/export; python -m SimpleHTTPServer %d )" % port
-      ssh_cmd = qa_utils.GetSSHCommand(master.primary, cmd)
-
-      try:
-        server_process = qa_utils.StartLocalCommand(ssh_cmd)
-        break
-      except OSError:
-        if port < 9000:
-          port += 1
-        else:
-          raise
+    cmd = ("wget -O busybox.img %s &> /dev/null &&"
+           " echo $(pwd)/busybox.img") % url
+    image = qa_utils.GetCommandOutput(pnode, cmd).strip()
 
-    url = "http://localhost:%d/%s" % (port, os.path.basename(image))
     AssertCommand(["gnt-instance", "reinstall",
-                   "--os-parameters", "os-image=" + url,
+                   "--os-parameters", "os-image=" + image,
                    "-f", instance.name])
 
-    AssertCommand(["rm", "-f", image])
-  finally:
-    server_process.terminate()
-
+  # Reinstall non existing local file
   AssertCommand(["gnt-instance", "reinstall",
                  "--os-parameters", "os-image=NonExistantOsForQa",
                  "-f", instance.name], fail=True)
 
+  # Reinstall non existing URL
   AssertCommand(["gnt-instance", "reinstall",
                  "--os-parameters", "os-image=http://NonExistantOsForQa",
                  "-f", instance.name], fail=True)
 
+  # Reinstall using OS scripts
   AssertCommand(["gnt-instance", "reinstall", "-f", instance.name])
 
   # Test with non-existant OS definition