Installation of a new kernel-rt package always update the default kernel even though UPDATEDEFAULT=no is set in /etc/sysconfig/kernel file.

Issue

• During installation of kernel-rt package the new-kernel-pkg script ignores UPDATEDEFAULT=no set in /etc/sysconfig/kernel file and always update the default kernel.

Eg:

• Default kernel version on the system is 3.6.11.2-rt33.39.el6rt.

# grubby --default-kernel
/boot/vmlinuz-3.6.11.2-rt33.39.el6rt.x86_64

• Set UPDATEDEFAULT=no and DEFAULTKERNEL=kernel-rt in /etc/sysconfig/kernel file.

# cat /etc/sysconfig/kernel 
# UPDATEDEFAULT specifies if new-kernel-pkg should make
# new kernels the default
UPDATEDEFAULT=no

# DEFAULTKERNEL specifies the default kernel package type
DEFAULTKERNEL=kernel-rt

• Install a new kernel-rt package.

# yum install kernel-rt

• Check default kernel version after installation of new kernel-rt package.

# grubby --default-kernel
/boot/vmlinuz-3.8.13-rt14.25.el6rt.x86_64

• Now default kernel is changed to 3.8.13-rt14.25.el6rt.