Boot partition full? It’s most likely old kernels, here’s some simple commands to clean up /boot by safely removing old kernels with yum
# Install yum-utils (if they aren’t already installed)
yum install yum-utils
# Cleanup old kernels and don’t keep more than 2
package-cleanup –oldkernels –count=2
You can actually make this a yum default by configuring /etc/yum.conf as follows
installonly_limit=2