To enable the priority-plugin the option of plugin should be enabled in /etc/yum.conf file as follows:
# vim /etc/yum.conf
[main] cachedir=/var/cache/yum/$basearch/$releasever keepcache=0 debuglevel=2 logfile=/var/log/yum.log exactarch=1 obsoletes=1 gpgcheck=1 plugins=1 installonly_limit=5 distroverpkg=centos-release The priorities plugin is available at two locations: By default enabled CentOS Extras Repository where yum-plugin-priority can be installed using following command : # yum install yum-plugin-priorities yum-utils sources which has README file with instructions to install the plugin in the archieve directory. Once the package is installed it should also be enabled in the /etc/yum/pluginconf.d/priorities.conf : [main] enabled = 1 Following the above steps enables the plugin.Now we can add priorities to the repositories by appending following line priority=N to the targeted repository,where N is integer ranging from 1 to 99. Repositories with the lowest numerical value have the highestpriority. It is best practice to give CentOS base and update repositories very high priority. The default priority for repositories is 99.