diff --git a/nixops/resources/elastic_ip.py b/nixops/resources/elastic_ip.py
index 6a461e0d4..74ba9675a 100644
--- a/nixops/resources/elastic_ip.py
+++ b/nixops/resources/elastic_ip.py
@@ -51,6 +51,15 @@ def show_type(self):
     def resource_id(self):
         return self.allocation_id
 
+    def get_physical_spec(self):
+        physical = {}
+        if self.public_ipv4:
+            physical['address'] = self.public_ipv4
+        return physical
+
+    def prefix_definition(self, attr):
+        return {('resources', 'elasticIPs'): attr}
+
     def connect(self, region):
         if self._client:
             return