diff --git a/labs/docker/kurento/Dockerfile b/labs/docker/kurento/Dockerfile
index ed3d61c803ff3c390f71ac2dab94c7b94df769f2..97dbf889259eeca09b76fdb364bd280d9b317c37 100644
--- a/labs/docker/kurento/Dockerfile
+++ b/labs/docker/kurento/Dockerfile
@@ -1,5 +1,7 @@
 FROM ubuntu:16.04
 
+ENV DEBIAN_FRONTEND noninteractive
+
 RUN apt-get update \
  && apt-get -y dist-upgrade \
  && apt-get install -y software-properties-common curl wget apt-transport-https
diff --git a/labs/docker/kurento/docker-entrypoint.sh b/labs/docker/kurento/docker-entrypoint.sh
index 747733084c2b0b27bf8d3c01a0e73117787f1de3..4d1d3a444ebd238994df8c48195f5027b68f6d4e 100755
--- a/labs/docker/kurento/docker-entrypoint.sh
+++ b/labs/docker/kurento/docker-entrypoint.sh
@@ -15,7 +15,8 @@ if [ -n "$KMS_STUN_IP" -a -n "$KMS_STUN_PORT" ]; then
   echo "stunServerPort=$KMS_STUN_PORT" >> /etc/kurento/modules/kurento/WebRtcEndpoint.conf.ini
 fi
 
-cat /etc/kurento/kurento.conf.json | sed '/^[ ]*\/\//d' | jq ".mediaServer.net.websocket.port = $PORT" > /etc/kurento/kurento.conf.json
+KMS_CONFIG=$(cat /etc/kurento/kurento.conf.json | sed '/^[ ]*\/\//d' | jq ".mediaServer.net.websocket.port = $PORT")
+echo $KMS_CONFIG > /etc/kurento/kurento.conf.json
 
 # Remove ipv6 local loop until ipv6 is supported
 cat /etc/hosts | sed '/::1/d' | tee /etc/hosts > /dev/null