Sysadmin Grub Help?

I just upgraded to centos 7.4 and not the server hangs on the grub command and won't boot. Anyone good at working with Grub or know how to get my system working again?

If this thread is in the wrong forum, please move it.

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Thanks!

 

I'm about to see my hard drive using the ls command.

Code:

ls (md/md2)

Was following the information here: https://www.linux.com/learn/how-rescue-non-booting-grub-2-Linux

 

This is what the doc uses

Code:

grub> set root=(hd0,1)
grub> linux /boot/vmlinuz-3.13.0-29-generic root=/dev/sda1
grub> initrd /boot/initrd.img-3.13.0-29-generic
grub> boot

I got the first line:

Code:

grub> set root=(md/md2)

Not sure about the second line. All my files are on (md/md2) so not sure if I would need root again???

Code:

grub> linux /boot/vmlinuz-3.10.0-693.2.2.el7.x86_64 root=????

Third line: don't see any initrd on the list? I only see initramfs. Would the line be:

Code:

grub> initramfs /boot/initramfs-3.10.0-514.26.2.el7.x86_64.img

 

Entering linux to start the second line gives me an error: "can't find the command 'linux'"

 

What ended up working:

Code:

grub> set prefix=(md/md2)/boot/grub2
grub> set root=(md/md2)
grub> insmod linux
grub> normal

Once the system restarted I ran:

Code:

grub2-mkconfig

Haven't rebooted yet, so not sure if the make config command works.

 

So, I rebooted and still getting the grub prompt.

I guess grub2-mkconfig didn't work.

Any ideas? How to get the grub to work on boot?

 

Was looking at this file: Configuring Grub 2 on CentOS 7 to Dual Boot with Windows 7

Maybe using the below is what's needed?

Code:

grub2-mkconfig --output=/boot/grub2/grub.cfg

 

This is on my dedicated server at OVH.

Using default kernel. Yea, I have IPMI access.

I can get system booted with the hack above from Grub. Can't seem to get the grub to update or don't know what I need to do to get the grub working again. Always boots to the grub prompt.

 

I'm not super savvy with the grub stuff, but I think it's something in the grub config that's the issue. I don't think anything will log if the grub prompt is as far as the system gets booting. I could be totally wrong though.

 

Code:

# awk -F\' '$1=="menuentry " {print $2}' /etc/grub2.cfg
CentOS Linux (3.10.0-693.2.2.el7.x86_64) 7 (Core)
CentOS Linux (3.10.0-514.26.2.el7.x86_64) 7 (Core)
CentOS Linux (3.10.0-514.26.1.el7.x86_64) 7 (Core)
CentOS Linux (3.10.0-514.21.2.el7.x86_64) 7 (Core)
CentOS Linux (3.10.0-514.21.1.el7.x86_64) 7 (Core)
CentOS Linux (0-rescue-1e98a4cc1263468b9f9a12e365316b95) 7 (Core)

 

Would that be the same as: Sysadmin - Grub Help?

 

Code:

# grub2-set-default 0
# grub2-mkconfig -o /boot/grub2/grub.cfg
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-3.10.0-693.2.2.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-693.2.2.el7.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-514.26.2.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-514.26.2.el7.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-514.26.1.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-514.26.1.el7.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-514.21.2.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-514.21.2.el7.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-514.21.1.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-514.21.1.el7.x86_64.img
Found linux image: /boot/vmlinuz-0-rescue-1e98a4cc1263468b9f9a12e365316b95
Found initrd image: /boot/initramfs-0-rescue-1e98a4cc1263468b9f9a12e365316b95.img
done

I'll try the reboot now.

 

Nope. Grub command prompt.