How does createrepo work. How does yum understand parse its files. A conceptual explanation

Question

I am not looking for a how-to on creating a repo (createrepo) or using yum.

I want to understand how they work together.
I want to know what files yum looks at and why, what those files contain.
I want to understand the structure of the repo and its files. I want to understand how it all works together.
I have read many how-to's, I am looking for a more conceptual understanding.

I working with Centos 6 32bit.

Solution 1

Createrepo creates some informational files that can be used by yum tool while fetching data from a reposiotry. The files are filelists.xml,repomd.xml etc. the below tutorial explains the complete yum working. How does YUM work?

Solution 2

I can't provide a complete answer to the entire flow of yum, but the following page describes createrepo and the rpm-metadata provided by createrepo.

http://createrepo.baseurl.org/