diff --git a/ansible/roles/ironic-enrolment/tasks/node.yml b/ansible/roles/ironic-enrolment/tasks/node.yml
index 5bc086b..5b73b0a 100644
--- a/ansible/roles/ironic-enrolment/tasks/node.yml
+++ b/ansible/roles/ironic-enrolment/tasks/node.yml
@@ -87,10 +87,21 @@
               --{{ iface }}-interface {{ node.ironic_config[iface + '_interface'] }}
             {% endif %}
           {% endfor %}
-          {% for key, val in (
-               node.ironic_config.properties | default({})).iteritems() %}
+          {% for key, val in properties.iteritems() %}
             --property '{{ key }}={{ val }}'
           {% endfor %}
+      vars:
+        properties: "{{ default_properties | combine(custom_properties) }}"
+        custom_properties: "{{ node.ironic_config.get('properties', {}) }}"
+        # Although properties are not required for scheduling, the os_ironic module
+        # adds silly defaults that cause the validation API call to fail,
+        # preventing deployment.  We add them here because the os_ironic module
+        # uses unusual names (cpus, ram, disk_size) for scheduling properties,
+        # and doesn't support setting other properties.
+        default_properties:
+          cpus: "{{ node.vcpus }}"
+          memory_mb: "{{ node.memory_mb }}"
+          local_gb: "{{ node.volumes[0].capacity | size_string_to_gb if node.volumes | length > 0 else 0 }}"
 
     - name: Add Ironic node traits
       command: >-
diff --git a/releasenotes/notes/default-properties-a59636e41be05d66.yaml b/releasenotes/notes/default-properties-a59636e41be05d66.yaml
new file mode 100644
index 0000000..19359ba
--- /dev/null
+++ b/releasenotes/notes/default-properties-a59636e41be05d66.yaml
@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    Adds support for setting default properties on ironic nodes. This avoids an
+    issue where nodes are registered with the standard scheduling properties
+    all set to 1, causing ironic validation failures. See `story 2004908
+    <https://storyboard.openstack.org/#!/story/2004908>`__ for details.