cAdvisor needs access to dmsetup for devicemapper info

Add device-mapper to yum install in base image

Author: smarterclayton

images/base/Dockerfile

@@ -7,5 +7,6 @@
 FROM centos:centos7
 
 # components from EPEL must be installed in a separate yum install step
-RUN yum install -y git tar wget socat hostname sysvinit-tools util-linux bsdtar epel-release ethtool iptables && \
+RUN yum install -y git tar wget hostname sysvinit-tools util-linux bsdtar epel-release \
+    socat ethtool device-mapper iptables && \
     yum clean all