yum repository - How it works

Its for new comers ..


Needs and use cases
1. You wish to install some tools or packages 
2. you wish to install all the dependent packages automatically

Options:
1. either you download all the software manually using rpm
2. run "make/configure" commands to install the software/tools/packages
3. yum install <package_name>

Option-3 : yum install <package_name>

How it works, simple
1. /usr/bin/yum will look at yum repositories,
2. search for that package name 
3. if found, downloads and installs it, in to the local machine

What is yum repository and how to configure it

yum repository are place where Linux distribution packages/tools installation are stored, in forms like rpm etc, 
These repositories are access via htp/https protocol, which are configured in each yum repository configuration at :
  /etc/yum.repos.d/

Note : repo name ends with ".repo" in order to yum tool to search for it

Example :
 cat rdo-release.repo
[openstack-mitaka]
name=OpenStack Mitaka Repository
baseurl=http://cdnus.minefield.fr/centos/7/cloud/$basearch/openstack-mitaka/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-SIG-Cloud




Understanding yum repository configuration 
In above yum repository 
[openstack-mitaka] --> Name of repository
baseurl --> repository main url, where different types of repository will be available
enabled --> 1 = enabled, 0=disable, mean during yum install, this repo will not be searched for given package


What is "yum update", yum make , yum cache, etc

to be continue...