diff --git a/exercises/volumes.sh b/exercises/volumes.sh
index 3f75483..1f7c25f 100755
--- a/exercises/volumes.sh
+++ b/exercises/volumes.sh
@@ -41,7 +41,7 @@
 # returns a token and catalog of endpoints.  We use python to parse the token
 # and save it.
 
-TOKEN=`curl -s -d  "{\"auth\":{\"passwordCredentials\": {\"username\": \"$NOVA_USERNAME\", \"password\": \"$NOVA_PASSWORD\"}}}" -H "Content-type: application/json" http://$HOST_IP:5000/v2.0/tokens | python -c "import sys; import json; tok = json.loads(sys.stdin.read()); print tok['access']['token']['id'];"`
+TOKEN=`curl -s -d  "{\"auth\":{\"passwordCredentials\": {\"username\": \"$OS_USERNAME\", \"password\": \"$OS_PASSWORD\"}}}" -H "Content-type: application/json" ${OS_AUTH_URL%/}/tokens | python -c "import sys; import json; tok = json.loads(sys.stdin.read()); print tok['access']['token']['id'];"`
 
 # Launching a server
 # ==================