Create a group


yum-groups-manager -n "My Group" --id=mygroup --save=mygroups.xml --mandatory yum glibc rpm
createrepo -g /path/to/mygroups.xml /srv/my/repo

Find the package that provides a library

yum whatprovides *Xlib.h


RPM is either yum-versionlock or yum-plugin-versionlock


# add lock at current version
yum versionlock add PACKAGE
# list locked version
yum versionlock list
# delete an entry
yum versionlock delete PACKAGE
# blow away entire versionlock file
yum versionlock clear