service composition, WIP
diff --git a/xos/tosca/custom_types/xos.yaml b/xos/tosca/custom_types/xos.yaml
index 95fe2dc..87c96b4 100644
--- a/xos/tosca/custom_types/xos.yaml
+++ b/xos/tosca/custom_types/xos.yaml
@@ -1,6 +1,9 @@
 tosca_definitions_version: tosca_simple_yaml_1_0
 
 node_types:
+    tosca.nodes.Service:
+        derived_from: tosca.nodes.Root
+   
     tosca.nodes.Slice:
         derived_from: tosca.nodes.Root
         properties:
@@ -11,4 +14,8 @@
     tosca.relationships.MemberOfSlice:
         derived_from: tosca.relationships.Root
 
-    
\ No newline at end of file
+    tosca.relationships.MemberOfService:
+        derived_from: tosca.relationships.Root
+
+    tosca.relationships.TenantOfService:
+        derived_from: tosca.relationships.Root
diff --git a/xos/tosca/samples/composition.yaml b/xos/tosca/samples/composition.yaml
new file mode 100644
index 0000000..8340b21
--- /dev/null
+++ b/xos/tosca/samples/composition.yaml
@@ -0,0 +1,55 @@
+tosca_definitions_version: tosca_simple_yaml_1_0
+
+description: Template for deploying a single server with predefined properties.
+
+imports:
+   - custom_types/xos.yaml
+
+topology_template:
+  node_templates:
+    # CORD Services
+    service_volt:
+      type: tosca.nodes.Service
+      requirements:
+          - vcpe_tenant:
+              node: service_vcpe
+              relationship: tosca.relationships.IsTenantOf
+
+    service_vcpe:
+      type: tosca.nodes.Service
+      requirements:
+          - vbng_tenant:
+              node: service_vbng
+              relationship: tosca.relationships.IsTenantOf
+
+    service_vbng:
+      type: tosca.nodes.Service
+
+    mysite_tosca:
+      type: tosca.nodes.Slice
+      requirements:
+          - volt_service:
+              node: service_volt
+              relationship: tosca.relationships.MemberOfService
+
+    my_server:
+      type: tosca.nodes.Compute
+      capabilities:
+        # Host container properties
+        host:
+         properties:
+           num_cpus: 1
+           disk_size: 10 GB
+           mem_size: 4 MB
+        # Guest Operating System properties
+        os:
+          properties:
+            # host Operating System image properties
+            architecture: x86_64
+            type: linux
+            distribution: rhel
+            version: 6.5
+      requirements:
+          - slice:
+                node: mysite_tosca
+                relationship: tosca.relationships.MemberOfSlice