Fix fast track when exiting cleaning

When exiting cleaning, previously the agent token was purged
from ironic's database and agents continuing to run would not
be able to heartbeat to the conductor. With agent token, this
would orphan the agent such that it thought it had an agent
token, yet the conductor did not.

Change-Id: Id6f8609bcda369649d0f677aceed26ed5e72a313
(cherry picked from commit 5b785569b6)

ironic/conductor/cleaning.py

@@ -218,12 +218,13 @@ def do_next_clean_step(task, step_index):
     driver_internal_info.pop('clean_step_index', None)
     driver_internal_info.pop('cleaning_reboot', None)
     driver_internal_info.pop('cleaning_polling', None)
-    driver_internal_info.pop('agent_secret_token', None)
-    driver_internal_info.pop('agent_secret_token_pregenerated', None)
 
     # Remove agent_url
     if not utils.fast_track_able(task):
         driver_internal_info.pop('agent_url', None)
+        driver_internal_info.pop('agent_secret_token', None)
+        driver_internal_info.pop('agent_secret_token_pregenerated', None)
+
     node.driver_internal_info = driver_internal_info
     node.save()
     try:

ironic/tests/unit/conductor/test_cleaning.py

@@ -888,8 +888,9 @@ class DoNodeCleanTestCase(db_base.DbTestCase):
             self.config(fast_track=True, group='deploy')
 
         for info in ({'clean_steps': None, 'clean_step_index': None,
-                      'agent_url': 'test-url'},
-                     {'clean_steps': None, 'agent_url': 'test-url'}):
+                      'agent_url': 'test-url', 'agent_secret_token': 'magic'},
+                     {'clean_steps': None, 'agent_url': 'test-url',
+                      'agent_secret_token': 'it_is_a_kind_of_magic'}):
             # Resume where there are no steps, should be a noop
             tgt_prov_state = states.MANAGEABLE if manual else states.AVAILABLE
 
@@ -917,8 +918,12 @@ class DoNodeCleanTestCase(db_base.DbTestCase):
             if fast_track:
                 self.assertEqual('test-url',
                                  node.driver_internal_info.get('agent_url'))
+                self.assertIsNotNone(
+                    node.driver_internal_info.get('agent_secret_token'))
             else:
                 self.assertNotIn('agent_url', node.driver_internal_info)
+                self.assertNotIn('agent_secret_token',
+                                 node.driver_internal_info)
             mock_execute.reset_mock()
 
     def test__do_next_clean_step_automated_no_steps(self):

releasenotes/notes/fast-track-with-cleaning-438225116a11662d.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    Fixes a bug in "fast track" where Ironic would delete the ``agent token``
+    upon exiting cleaning steps. However, if we are in fast track mode, we can
+    preserve the token and continue operations with the agent as it is not
+    powered off during fast track operations.