When choosing CentOS, cookbooks/opennms-light/recipes/default.rb assumes it is going to be version 6

[agalue]

when "rhel"
home_dir = "/opt/opennms"
template "/etc/yum.repos.d/opennms-rhel6.repo" do
source "opennms.yum.repo.erb"
owner "root"
group "root"
mode "0644"
end

Instead of rhel6, you should use the proper version, otherwise it might work with CentOS 7, but it is not replicating a real environment.