Don't try to call GRUB when root UUID is not provided

We don't have a really working way to detect root UUID for whole
disk images at the moment, which results in an ignored traceback
every time install_bootloader is called with whole disk images in
UEFI mode. Avoid it by skipping GRUB2 if root UUID is unknown.

Change-Id: I84245538f59c664b72d1cafbca8d61be0978f489

ironic_python_agent/extensions/image.py

@@ -744,6 +744,13 @@ class ImageExtension(base.BaseAgentExtension):
                                 efi_system_part_uuid=efi_system_part_uuid):
                     return
 
+        # We don't have a working root UUID detection for whole disk images.
+        # Until we can do it, avoid a confusing traceback.
+        if root_uuid == '0x00000000' or root_uuid is None:
+            LOG.info('Not using grub2-install since root UUID is not provided.'
+                     ' Assuming a whole disk image')
+            return
+
         # In case we can't use efibootmgr for uefi we will continue using grub2
         LOG.debug('Using grub2-install to set up boot files')
         _install_grub2(device,

ironic_python_agent/tests/unit/extensions/test_image.py

@@ -95,6 +95,21 @@ class TestImageExtension(base.IronicAgentTest):
         )
         mock_iscsi_clean.assert_called_once_with(self.fake_dev)
 
+    @mock.patch.object(iscsi, 'clean_up', autospec=True)
+    @mock.patch.object(image, '_install_grub2', autospec=True)
+    def test__install_bootloader_no_root(self, mock_grub2, mock_iscsi_clean,
+                                         mock_execute, mock_dispatch):
+        mock_dispatch.side_effect = [
+            self.fake_dev, hardware.BootInfo(current_boot_mode='bios')
+        ]
+        self.agent_extension.install_bootloader(
+            root_uuid='0x00000000').join()
+        mock_dispatch.assert_any_call('get_os_install_device')
+        mock_dispatch.assert_any_call('get_boot_info')
+        self.assertEqual(2, mock_dispatch.call_count)
+        self.assertFalse(mock_grub2.called)
+        mock_iscsi_clean.assert_called_once_with(self.fake_dev)
+
     @mock.patch.object(hardware, 'is_md_device', lambda *_: False)
     @mock.patch.object(os.path, 'exists', lambda *_: False)
     @mock.patch.object(iscsi, 'clean_up', autospec=True)

releasenotes/notes/whole-disk-grub-0b1b8b9c44e31d28.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Avoids a traceback when using ``install_bootloader`` with whole disk
+    images. If the root UUID cannot be detected, don't try to call grub.