diff --git a/Dockerfile b/Dockerfile
index 58479fe..dcb1e62 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,8 @@
 FROM alpine:3.10.3
 LABEL maintainer "Stefan Hoffmann, Nils Jakobi"
 
+VOLUME [ "/opt/data" ]
+
 # Configure cron
 COPY crontab /etc/cron/crontab
 
diff --git a/nodePoller.sh b/nodePoller.sh
index e6ffc7f..cfac272 100755
--- a/nodePoller.sh
+++ b/nodePoller.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 
 for i in 4 5 6 7
 do