diff --git a/nagios/Dockerfile.ubuntu_bionic b/nagios/Dockerfile.ubuntu_bionic
index 1cff7d8b..0dbf793e 100644
--- a/nagios/Dockerfile.ubuntu_bionic
+++ b/nagios/Dockerfile.ubuntu_bionic
@@ -1,6 +1,7 @@
 ARG FROM=docker.io/ubuntu:bionic
 FROM ${FROM}
 
+ENV DEBIAN_FRONTEND=noninteractive
 ENV APACHE_FRONTEND_PORT 8000
 ENV APACHE_FRONTEND_SECURE_PORT 8443
 ENV ES_DSL_VERSION=5.4.0
@@ -20,7 +21,7 @@ RUN apt-get -o Acquire::ForceIPv4=true -y update \
 RUN rm -f /usr/bin/python
 RUN ln -s /usr/bin/python3 /usr/bin/python
 
-RUN pip3 --no-cache-dir install --upgrade pip3 \
+RUN pip3 install --upgrade pip \
         && hash -r \
         && pip3 --no-cache-dir install --upgrade setuptools \
         && pip3 --no-cache-dir install --upgrade kubernetes \
diff --git a/nagios/Dockerfile.ubuntu_xenial b/nagios/Dockerfile.ubuntu_xenial
index 62129f37..6173b418 100644
--- a/nagios/Dockerfile.ubuntu_xenial
+++ b/nagios/Dockerfile.ubuntu_xenial
@@ -1,6 +1,7 @@
 ARG FROM=docker.io/ubuntu:xenial
 FROM ${FROM}
 
+ENV DEBIAN_FRONTEND=noninteractive
 ENV APACHE_FRONTEND_PORT 8000
 ENV APACHE_FRONTEND_SECURE_PORT 8443
 ENV ES_DSL_VERSION=5.4.0