url_string is required on Slave Instances.

master/bt5/slapos_cloud/PortalTypePropertySheetTemplateItem/property_sheet_list.xml

@@ -12,6 +12,7 @@
   <item>SlaveInstanceConstraint</item>
   <item>SoftwareInstance</item>
   <item>TextDocument</item>
+  <item>Url</item>
   <item>VariationRange</item>
  </portal_type>
  <portal_type id="Software Installation">

master/bt5/slapos_cloud/PropertySheetTemplateItem/portal_property_sheets/SlaveInstanceConstraint/url_string_property_constraint.xml

+<?xml version="1.0"?>
+<ZopeData>
+  <record id="1" aka="AAAAAAAAAAE=">
+    <pickle>
+      <global name="Property Existence Constraint" module="erp5.portal_type"/>
+    </pickle>
+    <pickle>
+      <dictionary>
+        <item>
+            <key> <string>_identity_criterion</string> </key>
+            <value>
+              <persistent> <string encoding="base64">AAAAAAAAAAI=</string> </persistent>
+            </value>
+        </item>
+        <item>
+            <key> <string>_range_criterion</string> </key>
+            <value>
+              <persistent> <string encoding="base64">AAAAAAAAAAM=</string> </persistent>
+            </value>
+        </item>
+        <item>
+            <key> <string>constraint_property</string> </key>
+            <value>
+              <tuple>
+                <string>url_string</string>
+              </tuple>
+            </value>
+        </item>
+        <item>
+            <key> <string>description</string> </key>
+            <value>
+              <none/>
+            </value>
+        </item>
+        <item>
+            <key> <string>id</string> </key>
+            <value> <string>url_string_property_constraint</string> </value>
+        </item>
+        <item>
+            <key> <string>portal_type</string> </key>
+            <value> <string>Property Existence Constraint</string> </value>
+        </item>
+      </dictionary>
+    </pickle>
+  </record>
+  <record id="2" aka="AAAAAAAAAAI=">
+    <pickle>
+      <global name="PersistentMapping" module="Persistence.mapping"/>
+    </pickle>
+    <pickle>
+      <dictionary>
+        <item>
+            <key> <string>data</string> </key>
+            <value>
+              <dictionary/>
+            </value>
+        </item>
+      </dictionary>
+    </pickle>
+  </record>
+  <record id="3" aka="AAAAAAAAAAM=">
+    <pickle>
+      <global name="PersistentMapping" module="Persistence.mapping"/>
+    </pickle>
+    <pickle>
+      <dictionary>
+        <item>
+            <key> <string>data</string> </key>
+            <value>
+              <dictionary/>
+            </value>
+        </item>
+      </dictionary>
+    </pickle>
+  </record>
+</ZopeData>

master/bt5/slapos_cloud/bt/revision

-118
\ No newline at end of file
+119
\ No newline at end of file

master/bt5/slapos_cloud/bt/template_portal_type_property_sheet_list

@@ -8,6 +8,7 @@ Slave Instance | Reference
 Slave Instance | SlaveInstanceConstraint
 Slave Instance | SoftwareInstance
 Slave Instance | TextDocument
+Slave Instance | Url
 Slave Instance | VariationRange
 Software Installation | Url
 Software Installation | VariationRange