Avoid using introspection start delays with non-managed boot

When boot is managed by the ironic side, a node is powered on
right after starting introspection. Inspector's own delays play
no role and may actually prevent introspectin from happening if
a node boots faster than it's whitelisted in the PXE filter.

This changes moves the delay handling later in the process and
only does it when manage_boot is True.

Change-Id: If7de8b66ea42eff2966c62a9a0529ab9a5c06f26
Story: #2007658
Task: #39745

ironic_inspector/conf/default.py

@@ -58,7 +58,9 @@ _OPTS = [
                help=_('The green thread pool size.')),
     cfg.IntOpt('introspection_delay',
                default=5,
-               help=_('Delay (in seconds) between two introspections.')),
+               help=_('Delay (in seconds) between two introspections. Only '
+                      'applies when boot is managed by ironic-inspector (i.e. '
+                      'manage_boot==True).')),
     cfg.ListOpt('ipmi_address_fields',
                 default=['ilo_address', 'drac_host', 'drac_address',
                          'cimc_address'],

ironic_inspector/introspect.py

@@ -65,25 +65,6 @@ def introspect(node_id, manage_boot=True, token=None):
     utils.executor().submit(_background_introspect, node_info, ironic)
 
 
-@node_cache.release_lock
-@node_cache.fsm_transition(istate.Events.wait)
-def _background_introspect(node_info, ironic):
-    global _LAST_INTROSPECTION_TIME
-
-    LOG.debug('Attempting to acquire lock on last introspection time')
-    with _LAST_INTROSPECTION_LOCK:
-        delay = (_LAST_INTROSPECTION_TIME - time.time()
-                 + CONF.introspection_delay)
-        if delay > 0:
-            LOG.debug('Waiting %d seconds before sending the next '
-                      'node on introspection', delay)
-            time.sleep(delay)
-        _LAST_INTROSPECTION_TIME = time.time()
-
-    node_info.acquire_lock()
-    _background_introspect_locked(node_info, ironic)
-
-
 def _persistent_ramdisk_boot(node):
     """If the ramdisk should be configured as a persistent boot device."""
     value = node.driver_info.get('force_persistent_boot_device', 'Default')
@@ -93,7 +74,27 @@ def _persistent_ramdisk_boot(node):
         return strutils.bool_from_string(value, False)
 
 
-def _background_introspect_locked(node_info, ironic):
+def _wait_for_turn(node_info):
+    """Wait for the node's turn to be introspected."""
+    global _LAST_INTROSPECTION_TIME
+
+    LOG.debug('Attempting to acquire lock on last introspection time',
+              node_info=node_info)
+    with _LAST_INTROSPECTION_LOCK:
+        delay = (_LAST_INTROSPECTION_TIME - time.time()
+                 + CONF.introspection_delay)
+        if delay > 0:
+            LOG.debug('Waiting %d seconds before sending the next '
+                      'node on introspection', delay, node_info=node_info)
+            time.sleep(delay)
+        _LAST_INTROSPECTION_TIME = time.time()
+
+
+@node_cache.release_lock
+@node_cache.fsm_transition(istate.Events.wait)
+def _background_introspect(node_info, ironic):
+    node_info.acquire_lock()
+
     # TODO(dtantsur): pagination
     macs = list(node_info.ports())
     if macs:
@@ -122,6 +123,8 @@ def _background_introspect_locked(node_info, ironic):
             raise utils.Error(_('Failed to set boot device to PXE: %s') % exc,
                               node_info=node_info)
 
+        _wait_for_turn(node_info)
+
         try:
             ironic.set_node_power_state(node_info.uuid, 'rebooting')
         except Exception as exc:

ironic_inspector/test/unit/test_introspect.py

@@ -400,6 +400,24 @@ class TestIntrospect(BaseTest):
         # updated to the current time.time()
         self.assertEqual(42, introspect._LAST_INTROSPECTION_TIME)
 
+    @mock.patch.object(time, 'time', autospec=True)
+    def test_introspection_no_delay_without_manage_boot(self, time_mock,
+                                                        client_mock,
+                                                        start_mock):
+        time_mock.return_value = 42
+        introspect._LAST_INTROSPECTION_TIME = 40
+        CONF.set_override('introspection_delay', 10)
+
+        self._prepare(client_mock)
+        start_mock.return_value = self.node_info
+        self.node_info.manage_boot = False
+
+        introspect.introspect(self.uuid, manage_boot=False)
+
+        self.assertFalse(self.sleep_fixture.mock.called)
+        # not updated
+        self.assertEqual(40, introspect._LAST_INTROSPECTION_TIME)
+
     @mock.patch.object(time, 'time', autospec=True)
     def test_introspection_delay_not_needed(self, time_mock, client_mock,
                                             start_mock):

releasenotes/notes/unmanaged-delay-d39871e1346d9448.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    No longer uses introspection delay for nodes with ``manage_boot==False``
+    (i.e. boot is managed by ironic). It is useless and may actually break
+    introspection if a node boots before it gets whitelisted in the PXE filter.