There are two ways to exclude kernel being updated by yum:
1) You can edit /etc/yum.conf file
Use a text editor such like pico or nano to edit /etc/yum.conf:
# nano -w /etc/yum.conf
# nano -w /etc/yum.conf
Append/modify exclude directive line under [main] section, enter:
exclude=kernel*
Save and close the file. Try, updating the system without updating the Linux kernel:
# yum -y update
This is a permanent option, so you don’t need pass the -x option to yum command.
2) Provide the -x parameter to exclude kernel from updates via yum
The command is as follows to skip kernel update on CLI:
# yum -x ‘kernel*’ update