xenapi: remove pv detection

It was assumed that pygrub is there in domU, so that the RAW and unknown
disks were attached to domU and investigated with pygrub to find out if
PV could be used. This patch removes this functionality. Also some
cleanup is made around the ImageType mess.

From now RAW and unknown disks will not be investigated for PV-ness and
will boot as HVM.

Fixes bug 1196570

Change-Id: If84b93cee36938257b7ad0fa44b3b22878520506

nova/tests/virt/xenapi/stubs.py

@@ -83,12 +83,6 @@ def fake_stream_disk(*args, **kwargs):
     stubs.Set(vm_utils, '_stream_disk', fake_stream_disk)
 
 
-def stubout_is_vdi_pv(stubs):
-    def f(_1):
-        return False
-    stubs.Set(vm_utils, '_is_vdi_pv', f)
-
-
 def stubout_determine_is_pv_objectstore(stubs):
     """Assumes VMs stu have PV kernels."""
 

nova/tests/virt/xenapi/test_xenapi.py

@@ -147,7 +147,7 @@ def get_fake_device_info():
     return fake
 
 
-def stub_vm_utils_with_vdi_attached_here(function, should_return=True):
+def stub_vm_utils_with_vdi_attached_here(function):
     """
     vm_utils.with_vdi_attached_here needs to be stubbed out because it
     calls down to the filesystem to attach a vdi. This provides a
@@ -163,19 +163,13 @@ def fake_vdi_attached_here(*args, **kwargs):
         def fake_image_download(*args, **kwargs):
             pass
 
-        def fake_is_vdi_pv(*args, **kwargs):
-            return should_return
-
         orig_vdi_attached_here = vm_utils.vdi_attached_here
         orig_image_download = fake_image._FakeImageService.download
-        orig_is_vdi_pv = vm_utils._is_vdi_pv
         try:
             vm_utils.vdi_attached_here = fake_vdi_attached_here
             fake_image._FakeImageService.download = fake_image_download
-            vm_utils._is_vdi_pv = fake_is_vdi_pv
             return function(self, *args, **kwargs)
         finally:
-            vm_utils._is_vdi_pv = orig_is_vdi_pv
             fake_image._FakeImageService.download = orig_image_download
             vm_utils.vdi_attached_here = orig_vdi_attached_here
 
@@ -328,7 +322,6 @@ def setUp(self):
         xenapi_fake.create_network('fake', CONF.flat_network_bridge)
         stubs.stubout_session(self.stubs, stubs.FakeSessionForVMTests)
         stubs.stubout_get_this_vm_uuid(self.stubs)
-        stubs.stubout_is_vdi_pv(self.stubs)
         stubs.stub_out_vm_methods(self.stubs)
         fake_processutils.stub_out_processutils_execute(self.stubs)
         self.user_id = 'fake'
@@ -810,10 +803,9 @@ def test_spawn_fail_cleanup_3(self):
         # No additional VMs should be found.
         self.assertEqual(start_vms, end_vms)
 
-    @stub_vm_utils_with_vdi_attached_here
     def test_spawn_raw_glance(self):
         self._test_spawn(IMAGE_RAW, None, None)
-        self.check_vm_params_for_linux()
+        self.check_vm_params_for_windows()
 
     def test_spawn_vhd_glance_linux(self):
         self._test_spawn(IMAGE_VHD, None, None,
@@ -1886,19 +1878,17 @@ def test_windows_vhd(self):
     def test_linux_vhd(self):
         self.assert_pv_status(vm_utils.ImageType.DISK_VHD, 'linux', True)
 
-    @stub_vm_utils_with_vdi_attached_here
     def test_raw(self):
-        self.assert_pv_status(vm_utils.ImageType.DISK_RAW, 'linux', True)
+        self.assert_pv_status(vm_utils.ImageType.DISK_RAW, 'linux', False)
 
     def test_disk(self):
         self.assert_pv_status(vm_utils.ImageType.DISK, None, True)
 
     def test_iso(self):
         self.assert_pv_status(vm_utils.ImageType.DISK_ISO, None, False)
 
-    @stub_vm_utils_with_vdi_attached_here
     def test_none(self):
-        self.assert_pv_status(None, None, True)
+        self.assert_pv_status(None, None, False)
 
 
 class CompareVersionTestCase(test.TestCase):

nova/virt/xenapi/vm_utils.py

@@ -1436,24 +1436,27 @@ def determine_disk_image_type(image_meta):
     disk_format = image_meta['disk_format']
 
     disk_format_map = {
-        'ami': 'DISK',
-        'aki': 'KERNEL',
-        'ari': 'RAMDISK',
-        'raw': 'DISK_RAW',
-        'vhd': 'DISK_VHD',
-        'iso': 'DISK_ISO',
+        'ami': ImageType.DISK,
+        'aki': ImageType.KERNEL,
+        'ari': ImageType.RAMDISK,
+        'raw': ImageType.DISK_RAW,
+        'vhd': ImageType.DISK_VHD,
+        'iso': ImageType.DISK_ISO,
     }
 
     try:
-        image_type_str = disk_format_map[disk_format]
+        image_type = disk_format_map[disk_format]
     except KeyError:
         raise exception.InvalidDiskFormat(disk_format=disk_format)
 
-    image_type = getattr(ImageType, image_type_str)
-
     image_ref = image_meta['id']
+
+    params = {
+        'image_type_str': ImageType.to_string(image_type),
+        'image_ref': image_ref
+    }
     LOG.debug(_("Detected %(image_type_str)s format for image %(image_ref)s"),
-              {'image_type_str': image_type_str, 'image_ref': image_ref})
+              params)
 
     return image_type
 
@@ -1463,21 +1466,15 @@ def determine_is_pv(session, vdi_ref, disk_image_type, os_type):
     Determine whether the VM will use a paravirtualized kernel or if it
     will use hardware virtualization.
 
-        1. Glance (VHD): then we use `os_type`, raise if not set
+        1. Glance (VHD): if `os_type` is windows, HVM, otherwise PV
 
-        2. Glance (DISK_RAW): use Pygrub to figure out if pv kernel is
-           available
+        2. Glance (DISK_RAW): HVM
 
-        3. Glance (DISK): pv is assumed
+        3. Glance (DISK): PV
 
-        4. Glance (DISK_ISO): no pv is assumed
+        4. Glance (DISK_ISO): HVM
 
-        5. Boot From Volume - without image metadata (None): attempt to
-           use Pygrub to figure out if the volume stores a PV VM or a
-           HVM one. Log a warning, because there may be cases where the
-           volume is RAW (in which case using pygrub is fine) and cases
-           where the content of the volume is VHD, and pygrub might not
-           work as expected.
+        5. Boot From Volume - without image metadata (None): use HVM
            NOTE: if disk_image_type is not specified, instances launched
            from remote volumes will have to include kernel and ramdisk
            because external kernel and ramdisk will not be fetched.
@@ -1492,20 +1489,15 @@ def determine_is_pv(session, vdi_ref, disk_image_type, os_type):
             is_pv = True
     elif disk_image_type == ImageType.DISK_RAW:
         # 2. RAW
-        with vdi_attached_here(session, vdi_ref, read_only=True) as dev:
-            is_pv = _is_vdi_pv(dev)
+        is_pv = False
     elif disk_image_type == ImageType.DISK:
         # 3. Disk
         is_pv = True
     elif disk_image_type == ImageType.DISK_ISO:
         # 4. ISO
         is_pv = False
     elif not disk_image_type:
-        LOG.warning(_("Image format is None: trying to determine PV status "
-                      "using pygrub; if instance with vdi %s does not boot "
-                      "correctly, try with image metadata.") % vdi_ref)
-        with vdi_attached_here(session, vdi_ref, read_only=True) as dev:
-            is_pv = _is_vdi_pv(dev)
+        is_pv = False
     else:
         raise exception.NovaException(_("Unknown image format %s") %
                                       disk_image_type)
@@ -2018,27 +2010,6 @@ def _get_this_vm_ref(session):
     return session.call_xenapi("VM.get_by_uuid", get_this_vm_uuid())
 
 
-def _is_vdi_pv(dev):
-    LOG.debug(_("Running pygrub against %s"), dev)
-    dev_path = utils.make_dev_path(dev)
-    try:
-        out, err = utils.execute('pygrub', '-qn', dev_path, run_as_root=True)
-        for line in out:
-            # try to find kernel string
-            m = re.search('(?<=kernel:)/.*(?:>)', line)
-            if m and m.group(0).find('xen') != -1:
-                LOG.debug(_("Found Xen kernel %s") % m.group(0))
-                return True
-        LOG.debug(_("No Xen kernel found.  Booting HVM."))
-    except processutils.ProcessExecutionError:
-        LOG.exception(_("Error while executing pygrub! Please, ensure the "
-                        "binary is installed correctly, and available in your "
-                        "PATH; on some Linux distros, pygrub may be installed "
-                        "in /usr/lib/xen-X.Y/bin/pygrub. Attempting to boot "
-                        "in HVM mode."))
-    return False
-
-
 def _get_partitions(dev):
     """Return partition information (num, size, type) for a device."""
     dev_path = utils.make_dev_path(dev)