if the user provides a uuid and it exists, allow that to tie to the i…

…nstance, which allows the user to update the instance based on the UUID (includeding updating the hostname) should they choose to do so.

awx/main/managers.py

@@ -101,11 +101,13 @@ class InstanceManager(models.Manager):
     instance or role.
     """
 
+    UUID_DEFAULT = '00000000-0000-0000-0000-000000000000'
+
     def me(self):
         """Return the currently active instance."""
         # If we are running unit tests, return a stub record.
         if settings.IS_TESTING(sys.argv) or hasattr(sys, '_called_from_test'):
-            return self.model(id=1, hostname=settings.CLUSTER_HOST_ID, uuid='00000000-0000-0000-0000-000000000000')
+            return self.model(id=1, hostname=settings.CLUSTER_HOST_ID, uuid=self.UUID_DEFAULT)
 
         node = self.filter(hostname=settings.CLUSTER_HOST_ID)
         if node.exists():
@@ -115,6 +117,7 @@ def me(self):
     def register(self, uuid=None, hostname=None, ip_address=None, node_type='hybrid', defaults=None):
         if not hostname:
             hostname = settings.CLUSTER_HOST_ID
+
         with advisory_lock('instance_registration_%s' % hostname):
             if settings.AWX_AUTO_DEPROVISION_INSTANCES:
                 # detect any instances with the same IP address.
@@ -127,11 +130,21 @@ def register(self, uuid=None, hostname=None, ip_address=None, node_type='hybrid'
                         other_inst.save(update_fields=['ip_address'])
                         logger.warning("IP address {0} conflict detected, ip address unset for host {1}.".format(ip_address, other_hostname))
 
-            # Return existing instance that matches hostname
+            # get the instance based on the hostname
             instance = self.filter(hostname=hostname)
+
+            # Check or update the existing uuid
+            if uuid != None and uuid != self.UUID_DEFAULT:
+                if self.filter(uuid=uuid).exists():
+                    instance = self.filter(uuid=uuid)
+
+            # Return existing instance
             if instance.exists():
                 instance = instance.get()
                 update_fields = []
+                if instance.hostname != hostname:
+                    instance.hostname = hostname
+                    update_fields.append('hostname')
                 if instance.ip_address != ip_address:
                     instance.ip_address = ip_address
                     update_fields.append('ip_address')