[CentOS] selinux & rsyncd: Allowing global read for backup

Wed Jan 4 11:59:45 UTC 2017
Kenneth Porter <shiva at sewingwitch.com>

I want to set up rsyncd to expose the whole drive read-only to BackupPC 
running on another machine. So I need to set selinux to allow this. 
According to the Fedora wiki I can do so like this:

setsebool -P rsync_disable_trans 1


But when I run the command on CentOS 7.3 it tells me that this bool is not 
defined. So what do I do now?

(Everything works fine if I set SELinux to permissive.)