Grub prompt after 'yum update' (CentOS 6.9)

Question

It seems the system can't boot correctly after running a yum update and grub prompt appears. I'm not sure but maybe memory was exhausted in the process. The thing is I don't know what is the real issue and how to solve it. When I try with these commands:

grub>boot
Error 8: Kernel must be loaded before booting

grub>root (hd0,0)
Filesystem type is ext2fs, partition type 0x83

I've checked some topics in the forums with no success.

Any help will be appreciated.

Many thanks

P.S. I don't have a CD or similar for booting purposes. It's a server from vultr and this was the response from them: "the instance seems to be sitting at a grub prompt, you will need to access the host from the console and troubleshoot the issue from there".

Answer 1

From grub.conf Note that you do not have to rerun grub after making changes to this file
NOTICE: You do not have a /boot partition. This means that all kernel and initrd paths are relative to /, eg. root (hd0,0)
kernel /boot/vmlinuz-version ro root=/dev/vda1
initrd /boot/initrd-[generic-]version.img

In terminal:
grub>root (hd0,0)
grub>kernel /boot/vmlinuz-version ro root=/dev/vda1
grub>initrd /boot/initrd-[generic-]version.img
grub>boot