diff --git a/Dockerfile.tester b/Dockerfile.tester
index e36faad..6cc827b 100644
--- a/Dockerfile.tester
+++ b/Dockerfile.tester
@@ -15,7 +15,7 @@
  cd openvswitch-2.5.0 && \
  ./configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var --disable-ssl && make && make install)
 RUN service openvswitch-switch restart || /bin/true
-RUN pip install -U scapy scapy-ssl_tls monotonic configObj docker-py pyyaml nsenter pyroute2 netaddr
+RUN pip install -U scapy scapy-ssl_tls monotonic configObj docker-py pyyaml nsenter pyroute2 netaddr python-daemon
 RUN mv /usr/sbin/tcpdump /sbin/
 RUN ln -sf /sbin/tcpdump /usr/sbin/tcpdump
 WORKDIR /root