diff --git a/xml/constraints-2.6.rng b/xml/constraints-2.6.rng
new file mode 100644
index 0000000000..17f7afac02
--- /dev/null
+++ b/xml/constraints-2.6.rng
@@ -0,0 +1,252 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<grammar xmlns="http://relaxng.org/ns/structure/1.0" 
+         datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
+  <start>
+      <ref name="element-constraints"/>
+  </start>
+
+  <define name="element-constraints">
+    <element name="constraints">
+      <zeroOrMore>
+        <choice>
+          <ref name="element-location"/>
+          <ref name="element-colocation"/>
+          <ref name="element-order"/>
+          <ref name="element-rsc_ticket"/>
+        </choice>
+      </zeroOrMore>
+    </element>
+  </define>
+
+  <define name="element-location">
+    <element name="rsc_location">
+      <attribute name="id"><data type="ID"/></attribute>
+      <choice>
+        <group>
+          <attribute name="rsc"><data type="IDREF"/></attribute>
+          <optional>
+            <attribute name="role">
+              <ref name="attribute-roles"/>
+            </attribute>
+          </optional>
+        </group>
+        <oneOrMore>
+          <ref name="element-resource-set"/>
+        </oneOrMore>
+      </choice>
+      <choice>
+        <group>
+          <externalRef href="score.rng"/>
+          <attribute name="node"><text/></attribute>
+        </group>
+        <oneOrMore>
+          <externalRef href="rule.rng"/>
+        </oneOrMore>
+      </choice>
+      <optional>
+        <ref name="element-lifetime"/>
+      </optional>
+      <optional>
+        <attribute name="resource-discovery">
+          <ref name="attribute-discovery"/>
+        </attribute>
+      </optional>
+    </element>
+  </define>
+
+  <define name="element-resource-set">
+    <element name="resource_set">
+      <choice>
+        <attribute name="id-ref"><data type="IDREF"/></attribute>
+        <group>
+          <attribute name="id"><data type="ID"/></attribute>
+          <optional>
+            <attribute name="sequential"><data type="boolean"/></attribute>
+          </optional>
+          <optional>
+            <attribute name="require-all"><data type="boolean"/></attribute>
+          </optional>
+          <optional>
+            <attribute name="ordering">
+              <choice>
+                <value>group</value>
+                <value>listed</value>
+              </choice>
+            </attribute>
+          </optional>
+          <optional>
+            <attribute name="action">
+              <ref name="attribute-actions"/>
+            </attribute>
+          </optional>
+          <optional>
+            <attribute name="role">
+              <ref name="attribute-roles"/>
+            </attribute>
+          </optional>
+          <optional>
+            <externalRef href="score.rng"/>
+          </optional>
+          <oneOrMore>
+            <element name="resource_ref">
+              <attribute name="id"><data type="IDREF"/></attribute>
+            </element>
+          </oneOrMore>
+        </group>
+      </choice>
+    </element>
+  </define>
+
+  <define name="element-colocation">
+    <element name="rsc_colocation">
+      <attribute name="id"><data type="ID"/></attribute>
+      <optional>
+        <choice>
+          <externalRef href="score.rng"/>
+          <attribute name="score-attribute"><text/></attribute>
+          <attribute name="score-attribute-mangle"><text/></attribute>
+        </choice>
+      </optional>
+      <optional>
+        <ref name="element-lifetime"/>
+      </optional>
+      <choice>
+        <oneOrMore>
+          <ref name="element-resource-set"/>
+        </oneOrMore>
+        <group>
+          <attribute name="rsc"><data type="IDREF"/></attribute>
+          <attribute name="with-rsc"><data type="IDREF"/></attribute>
+          <optional>
+            <attribute name="node-attribute"><text/></attribute>
+          </optional>
+          <optional>
+            <attribute name="rsc-role">
+              <ref name="attribute-roles"/>
+            </attribute>
+          </optional>
+          <optional>
+            <attribute name="with-rsc-role">
+              <ref name="attribute-roles"/>
+            </attribute>
+          </optional>
+        </group>
+      </choice>
+    </element>
+  </define>
+
+  <define name="element-order">
+    <element name="rsc_order">
+      <attribute name="id"><data type="ID"/></attribute>
+      <optional>
+        <ref name="element-lifetime"/>
+      </optional>
+      <optional>
+        <attribute name="symmetrical"><data type="boolean"/></attribute>
+      </optional>
+      <optional>
+        <attribute name="require-all"><data type="boolean"/></attribute>
+      </optional>
+      <optional>
+        <choice>
+          <externalRef href="score.rng"/>
+          <attribute name="kind">
+            <ref name="order-types"/>
+          </attribute>
+        </choice>
+      </optional>
+      <choice>
+        <oneOrMore>
+          <ref name="element-resource-set"/>
+        </oneOrMore>
+        <group>
+          <attribute name="first"><data type="IDREF"/></attribute>
+          <attribute name="then"><data type="IDREF"/></attribute>
+          <optional>
+            <attribute name="first-action">
+              <ref name="attribute-actions"/>
+            </attribute>
+          </optional>
+          <optional>
+            <attribute name="then-action">
+              <ref name="attribute-actions"/>
+            </attribute>
+          </optional>
+        </group>
+      </choice>
+    </element>
+  </define>
+ 
+  <define name="element-rsc_ticket">
+    <element name="rsc_ticket">
+      <attribute name="id"><data type="ID"/></attribute>
+      <choice>
+        <oneOrMore>
+          <ref name="element-resource-set"/>
+        </oneOrMore>
+        <group>
+          <attribute name="rsc"><data type="IDREF"/></attribute>
+          <optional>
+            <attribute name="rsc-role">
+              <ref name="attribute-roles"/>
+            </attribute>
+          </optional>
+        </group>
+      </choice>
+      <attribute name="ticket"><text/></attribute>
+      <optional>
+        <attribute name="loss-policy">
+          <choice>
+            <value>stop</value>
+            <value>demote</value>
+            <value>fence</value>
+            <value>freeze</value>
+          </choice>
+        </attribute>
+      </optional>
+    </element>
+  </define>
+
+  <define name="attribute-discovery">
+    <choice>
+      <value>always</value>
+      <value>never</value>
+      <value>exclusive</value>
+    </choice>
+  </define>
+
+  <define name="attribute-actions">
+    <choice>
+      <value>start</value>
+      <value>promote</value>
+      <value>demote</value>
+      <value>stop</value>
+    </choice>
+  </define>
+      
+  <define name="attribute-roles">
+    <choice>
+      <value>Stopped</value>
+      <value>Started</value>
+      <value>Master</value>
+      <value>Slave</value>
+    </choice>
+  </define>
+
+  <define name="order-types">
+    <choice>
+      <value>Optional</value>
+      <value>Mandatory</value>
+      <value>Serialize</value>
+    </choice>
+  </define>
+
+  <define name="element-lifetime">
+    <element name="lifetime">
+      <oneOrMore>
+        <externalRef href="rule.rng"/>
+      </oneOrMore>
+    </element>
+  </define>
+  
+</grammar>