Hi there

For those running Linux VM's especially with VMware where you have several kernels installed - the default is often TOO quick to be able to select the kernel you want to use

Note this is AFTER the VM starts booting - it's the VM boot screen not the "Virtual Bios" where you can select the boot device.

Easy trick

edit the defaults file in etc/default/grub

GRUB_TIMEOUT=10
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=0
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rd.lvm.lv=centos/root rd.lvm.lv=centos/swap rhgb quiet"
GRUB_DISABLE_RECOVERY="true

set the TIMEOUT to the value you want - 10 is usually plenty long enough

If you want your specific kernel to be top of the list then starting with 0 look at the entries in the boot and set GRUB_DEFAULT = n (starting with 0) so if your kernel is 2nd in the list set GRUB_DEFAULT=1).

then re-generate grub and reboot

grub2-mkconfig -o /boot/grub2/grub.cfg

Cheers
jimbo