The OL7 EPEL x86_64 repository is currently throwing the "Metadata file does not match checksum" error for most yum operations (at least for me). This has been happening for a couple of days for both updateinfo.xml.gz and primary.xml.gz. yum clean all doesn't help.
One side effect of this is that most new installations of Oracle's Vagrant boxes on GitHub are failing. (The EPEL repository is enabled for the OL7 base box that's used for all but one of the Vagrant boxes, and the installation scripts include yum upgrade and/or yum install operations.)
I know that this is a temporary issue, but I wanted to get it out there in case anyone else encounters it.