you might try adding the following to core-site.xml seems like the error is talking about the root group. 

hadoop.proxyuser.root.groups=*
hadoop.proxyuser.root.hosts=*

If you are running cloudera manager, you need to add those in cloudera manager itself, the config is not in the traditional space, but instead in a seperate folder managed by cloudera for each individual service. Confusingly, the config is in the traditional space is for the "gateway".