This will be the time where setup HW watch dog should help. After the upgrade, before the reboot, setup the HW watch dog for 2-5 minutes. Setup the boot-old-

This will be the time where setup HW watch dog should help. After the upgrade, before the reboot, setup the HW watch dog for 2-5 minutes. Setup the boot-old-kernel flags as default in the uboot/EFI/grub/or your system boot loader. If the upgrade the successful (connect to back to the server) and function correctly, disable the "boot-old-kernel" flags in your bootloader. As always, do a lot of testing and automate those tests. You will be surprise how often a simple boot/reset/power cycle can fail if you repeat it over and over again in a weekend.