diff --git a/peel-extensions/src/main/resources/reference.spark.conf b/peel-extensions/src/main/resources/reference.spark.conf
index d2c0e9f7..aba0fcc5 100644
--- a/peel-extensions/src/main/resources/reference.spark.conf
+++ b/peel-extensions/src/main/resources/reference.spark.conf
@@ -22,6 +22,7 @@ system {
             slaves = ${system.default.config.slaves}
             # spark-env.sh entries
             env {
+                HADOOP_CONF_DIR = ${?system.hadoop-2.path.config}
                 JAVA_HOME = ${system.default.config.java.home}
                 SPARK_PID_DIR = "/tmp/spark-pid"
                 SPARK_MASTER_WEBUI_PORT = 8060