diff --git a/deployment/nova/nova-compute-container-puppet.yaml b/deployment/nova/nova-compute-container-puppet.yaml
index 96221b607f..902fd838c6 100644
--- a/deployment/nova/nova-compute-container-puppet.yaml
+++ b/deployment/nova/nova-compute-container-puppet.yaml
@@ -432,7 +432,7 @@ parameters:
   NovaHWMachineType:
     description: >
       To specify a default machine type per host architecture.
-    default: 'x86_64=pc-i440fx-rhel7.6.0,aarch64=virt-rhel7.6.0,ppc64=pseries-rhel7.6.0,ppc64le=pseries-rhel7.6.0'
+    default: ''
     type: string
     tags:
       - role_specific
diff --git a/releasenotes/notes/nova-machine-type-default-changed-27244a925f6d6200.yaml b/releasenotes/notes/nova-machine-type-default-changed-27244a925f6d6200.yaml
new file mode 100644
index 0000000000..ed237f81e1
--- /dev/null
+++ b/releasenotes/notes/nova-machine-type-default-changed-27244a925f6d6200.yaml
@@ -0,0 +1,6 @@
+---
+upgrade:
+  - |
+    The ``NovaHWMachineType`` parameter now defaults to an empty string with
+    per architecture machine type defaults instead being provided directly by
+    OpenStack Nova.