diff --git a/ansible/library/kolla_toolbox.py b/ansible/library/kolla_toolbox.py
index b3bc82dc42..569b060522 100644
--- a/ansible/library/kolla_toolbox.py
+++ b/ansible/library/kolla_toolbox.py
@@ -162,7 +162,9 @@ def use_docker(module):
                    "ANSIBLE_LOAD_CALLBACK_PLUGINS": "True"}
     job = client.exec_create(kolla_toolbox, command_line,
                              environment=environment, **kwargs)
-    json_output = client.exec_start(job)
+    json_output, error = client.exec_start(job, demux=True)
+    if error:
+        module.log(msg='Inner module stderr: %s' % error)
 
     try:
         output = json.loads(json_output)
diff --git a/releasenotes/notes/kolla-toolbox-demux-c5e8d27bc7214069.yaml b/releasenotes/notes/kolla-toolbox-demux-c5e8d27bc7214069.yaml
new file mode 100644
index 0000000000..5142566597
--- /dev/null
+++ b/releasenotes/notes/kolla-toolbox-demux-c5e8d27bc7214069.yaml
@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Fixes parsing of JSON output of inner modules called by ``kolla-toolbox``
+    when data was returned on standard error.
+    `LP#2080544 <https://launchpad.net/bugs/2080544>`__