diff --git a/ironic_lib/disk_utils.py b/ironic_lib/disk_utils.py
index cfcf6674..a2e3134b 100644
--- a/ironic_lib/disk_utils.py
+++ b/ironic_lib/disk_utils.py
@@ -501,7 +501,8 @@ def work_on_disk(dev, root_mb, swap_mb, ephemeral_mb, ephemeral_format,
         no ephemeral partition will be created.
     :param ephemeral_format: The type of file system to format the ephemeral
         partition.
-    :param image_path: Path for the instance's disk image.
+    :param image_path: Path for the instance's disk image. If ``None``,
+        the root partition is prepared but not populated.
     :param node_uuid: node's uuid. Used for logging.
     :param preserve_ephemeral: If True, no filesystem is written to the
         ephemeral block device, preserving whatever content it had (if the
@@ -526,6 +527,7 @@ def work_on_disk(dev, root_mb, swap_mb, ephemeral_mb, ephemeral_format,
         'root uuid': UUID of root partition
         'efi system partition uuid': UUID of the uefi system partition
         (if boot mode is uefi).
+        `partitions`: mapping of partition types to their device paths.
         NOTE: If key exists but value is None, it means partition doesn't
         exist.
     """
@@ -595,9 +597,13 @@ def work_on_disk(dev, root_mb, swap_mb, ephemeral_mb, ephemeral_format,
         if configdrive_file:
             utils.unlink_without_raise(configdrive_file)
 
-    populate_image(image_path, root_part, conv_flags=conv_flags)
-    LOG.info("Image for %(node)s successfully populated",
-             {'node': node_uuid})
+    if image_path is not None:
+        populate_image(image_path, root_part, conv_flags=conv_flags)
+        LOG.info("Image for %(node)s successfully populated",
+                 {'node': node_uuid})
+    else:
+        LOG.debug("Root partition for %s was created, but not populated",
+                  node_uuid)
 
     if swap_part:
         utils.mkfs(fs='swap', path=swap_part, label='swap1')
@@ -631,7 +637,7 @@ def work_on_disk(dev, root_mb, swap_mb, ephemeral_mb, ephemeral_format,
         with excutils.save_and_reraise_exception():
             LOG.error("Failed to detect %s", part)
 
-    return uuids_to_return
+    return dict(partitions=part_dict, **uuids_to_return)
 
 
 def list_opts():
diff --git a/ironic_lib/tests/test_disk_utils.py b/ironic_lib/tests/test_disk_utils.py
index 6d2ddfc6..2c311b47 100644
--- a/ironic_lib/tests/test_disk_utils.py
+++ b/ironic_lib/tests/test_disk_utils.py
@@ -200,6 +200,40 @@ class WorkOnDiskTestCase(base.IronicLibTestCase):
                                              cpu_arch="")
         mock_unlink.assert_called_once_with('fake-path')
 
+    @mock.patch.object(utils, 'mkfs', lambda fs, path, label=None: None)
+    @mock.patch.object(disk_utils, 'block_uuid', lambda p: 'uuid')
+    @mock.patch.object(disk_utils, 'populate_image', autospec=True)
+    def test_without_image(self, mock_populate):
+        ephemeral_part = '/dev/fake-part1'
+        swap_part = '/dev/fake-part2'
+        root_part = '/dev/fake-part3'
+        ephemeral_mb = 256
+        ephemeral_format = 'exttest'
+
+        self.mock_mp.return_value = {'ephemeral': ephemeral_part,
+                                     'swap': swap_part,
+                                     'root': root_part}
+        self.mock_ibd.return_value = True
+        calls = [mock.call(root_part),
+                 mock.call(swap_part),
+                 mock.call(ephemeral_part)]
+        res = disk_utils.work_on_disk(self.dev, self.root_mb,
+                                      self.swap_mb, ephemeral_mb,
+                                      ephemeral_format,
+                                      None, self.node_uuid)
+        self.assertEqual(self.mock_ibd.call_args_list, calls)
+        self.mock_mp.assert_called_once_with(self.dev, self.root_mb,
+                                             self.swap_mb, ephemeral_mb,
+                                             self.configdrive_mb,
+                                             self.node_uuid, commit=True,
+                                             boot_option="netboot",
+                                             boot_mode="bios",
+                                             disk_label=None,
+                                             cpu_arch="")
+        self.assertEqual(root_part, res['partitions']['root'])
+        self.assertEqual('uuid', res['root uuid'])
+        self.assertFalse(mock_populate.called)
+
     @mock.patch.object(utils, 'mkfs', lambda fs, path, label=None: None)
     @mock.patch.object(disk_utils, 'block_uuid', lambda p: 'uuid')
     @mock.patch.object(disk_utils, 'populate_image', lambda image_path,