Every linux kernal update requires reboot.
But there is workaround for that by patching the kernel with kexec.
First of all, we print out running kernel version:
# uname -r
2.6.32-71.29.1.el6.i686
Ok, we have to patch:
# yum update kernel*
Grab the kexec tools:
# yum install kexec-tools
Now we get last installed kernel version release and put it on a variable.
# latestkernel=`ls -t /boot/vmlinuz-* | sed "s/\/boot\/vmlinuz-//g" | head -n1`
# echo $latestkernel
2.6.32-220.4.1.el6.i686
Now we need to load the new kernel version in memory:
# kexec -l /boot/vmlinuz-${latestkernel} --initrd=/boot/initramfs-${latestkernel}.img --append="`cat /proc/cmdline`"
Finally, we can issue a reset:
# kexec -e
The system will “restart without restarting”..something like a fast reboot, without performing BIOS checks.
# uname -r
2.6.32-220.4.1.el6.i686
* Be aware that kernel reset will perform a connection reset as well, together with resetting your uptime.
