conservative method to validating that a job can be launched from a node

awx/main/models/jobs.py

@@ -606,11 +606,10 @@ class Job(UnifiedJob, JobOptions, SurveyJobMixin, JobNotificationMixin):
         evars.update(extra_vars)
         self.update_fields(extra_vars=json.dumps(evars))
 
-    def signal_start(self, **kwargs):
+    def _resources_sufficient_for_launch(self):
-        # Block cases that would cause the task manager to error
+        if self.job_type == PERM_INVENTORY_SCAN:
-        if self.inventory_id is None or self.project_id is None:
+            return self.inventory_id is not None
-            return False
+        return not (self.inventory_id is None or self.project_id is None)
-        return super(Job, self).signal_start(**kwargs)
 
     def display_artifacts(self):
         '''

awx/main/models/unified_jobs.py

@@ -561,6 +561,9 @@ class UnifiedJob(PolymorphicModel, PasswordFieldsModel, CommonModelNameNotUnique
         "Override in child classes, None value indicates this is not configurable"
         return None
 
+    def _resources_sufficient_for_launch(self):
+        return True
+
     def __unicode__(self):
         return u'%s-%s-%s' % (self.created, self.id, self.status)
 

awx/main/scheduler/__init__.py

@@ -121,7 +121,10 @@ class TaskManager():
                 job = spawn_node.unified_job_template.create_unified_job(**kv)
                 spawn_node.job = job
                 spawn_node.save()
-                can_start = job.signal_start(**kv)
+                if job._resources_sufficient_for_launch():
+                    can_start = job.signal_start(**kv)
+                else:
+                    can_start = False
                 if not can_start:
                     job.status = 'failed'
                     job.job_explanation = _("Job spawned from workflow could not start because it "