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

Solution Verified - Updated -


  • 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.


  • Default kernel version on the system is
# grubby --default-kernel
  • 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

# DEFAULTKERNEL specifies the default kernel package type
  • Install a new kernel-rt package.
# yum install kernel-rt
  • Check default kernel version after installation of new kernel-rt package.
# grubby --default-kernel
  • Now default kernel is changed to 3.8.13-rt14.25.el6rt.


  • Red Hat Enterprise Linux Server release 6.4 (Santiago)
  • kernel-rt
  • grubby

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