You’ve got two main options:
– grab a DVD of CentOS 7,
– use the Internet to download the equivalent iso distribution.
If you follow the second option, choose your CentOS mirror and get a copy of the last version of CentOS 7 x86_64.
I personally chose to download the DVD version (4GB) for the KVM host and the Everything version (7GB) for the VM repository but you can use the DVD version for both.
CentOS 7 is fully compatible with RHEL 7 because build from the same sources.
The main differences are:
- the Red Hat copyrights and logos are removed from the sources,
- the kernel is recompiled with additional drivers not supported by Red Hat.