diff --git a/ansible/roles/apache-hadoop/vars/main.yml b/ansible/roles/apache-hadoop/vars/main.yml
index b58d118cdc159014df3255558bb039b671989700..602b1befe131669b09a8877180c7a6e658a4fa06 100644
--- a/ansible/roles/apache-hadoop/vars/main.yml
+++ b/ansible/roles/apache-hadoop/vars/main.yml
@@ -3,5 +3,5 @@ mirror_url: "http://mirrors.myaegean.gr/apache/hadoop/common"
 version: "2.7.0"
 download_path: "/root"
 installation_path: "/usr/local"
-dfs_replication: {{ groups['slaves']|count }}
+dfs_replication: "{{ groups['slaves']|count }}"