diff --git a/tests/docker/dockerfiles/ubuntu.docker b/tests/docker/dockerfiles/ubuntu.docker
index dabbf2a8a4..c03520ce3f 100644
--- a/tests/docker/dockerfiles/ubuntu.docker
+++ b/tests/docker/dockerfiles/ubuntu.docker
@@ -1,7 +1,6 @@
 FROM ubuntu:16.04
 RUN echo "deb http://archive.ubuntu.com/ubuntu/ trusty universe multiverse" >> \
     /etc/apt/sources.list
-RUN apt-get update
 ENV PACKAGES flex bison \
     libusb-1.0-0-dev libiscsi-dev librados-dev libncurses5-dev libncursesw5-dev \
     libseccomp-dev libgnutls-dev libssh2-1-dev  libspice-server-dev \
@@ -13,6 +12,7 @@ ENV PACKAGES flex bison \
     libjemalloc-dev libcacard-dev libusbredirhost-dev libnfs-dev libcap-dev libattr1-dev \
     texinfo \
     gettext git make ccache python-yaml gcc clang sparse
-RUN apt-get -y install $PACKAGES
+RUN apt-get update && \
+    apt-get -y install $PACKAGES
 RUN dpkg -l $PACKAGES | sort > /packages.txt
 ENV FEATURES clang pyyaml