Web Hosting Talk : Web Hosting Main Forums : Hosting Security and Technology : how2check: lilo or grub -- remotely

[admin0]

Hi,

How do I determine if the bootloader in the system is lilo or grub when both the config files are present ?

[serial]

Good question. Basically when you update your boot loaders config file and write the MBR, then that boot loader takes over. I know that's not the answer you're looking for, but maybe it helps.

You could always reboot the machine and watch the boot process through a remote console device.

[heyzuess]

You could copy the boot sector to a file, using a command like this:

dd if=/dev/hda of=/tmp/boot-img.mbr bs=512 count=1

then download that file locally and use dd to write it to a floppy.

boot off the floppy at your local workstation.

I haven't tried it yet myself, but ran into the same problem before and thought of doing this to check.

[robinbalen]

Interesting idea with dd.

Last time a client asked us to check we got an on-site tech to watch the display output when we rebooted the box remotely

[bitserve]

I would ask the person who installed it.

[Angel78]

Just a question:

When you do: cat /root/anaconda-ks.cfg | grep bootloader

and get

bootloader

as result, then you are using GRUB, right?

[robinbalen]

I would ask the person who installed it.

This person didn't have a clue which was installed

[bitserve]

Originally posted by Angel78
When you do: cat /root/anaconda-ks.cfg | grep bootloader

and get

bootloader

as result, then you are using GRUB, right?

That seems like a good way to tell, if that file is there.
I would just do a less on the file though, it's not like it's that long. It should indicate whether you specified a different bootloader. Smart thinking.

[innova]

Lets play devils advocate


Why does it matter?

I use LiLo. It rules.

You can test a new kernel without fear of hosing your system that is 1500 miles away:

lilo -R <new_image_name>

Try that with grub! Mffff!

[microsol]

But with grub you can define a fall-back kernel (the last working one for example) in the grub conf. This one would boot if there would be a problem with the current one for whatever reason. As far as I know this doesn't work with lilo.

[admin0]

Thank you all for responding.


This is not a kernel upgrade issue, but just a question that someone asked me [to check my admin skills I guess, which in turn, all yours for this particular one.. ]

[b]cat /root/anaconda-ks.cfg | grep bootloader


bootloader
bootloader --useLilo



Is this the result of which it was at boot time, or at the current.
err.. what exactly am I looking at ?

The question is to tell him what bootloader will be used on his next reboot.

still waiting for that magic answer...

[heyzuess]

Use the dd method I suggested earlier - that will tell what is currently installed on the mbr, which will be the one that will be used on next boot.

Checking the anaconda-ks.cfg file just tells you what got installed. Your's looks like it was told to use Lilo - but that could have been changed.

[innova]

Lilo ALSO can use a "fallback" kernel.

Lilo -R <kernel image>

That kernel will ONLY be loaded at next boot. Therefore lets say your kernel is built wrong, you messed up, whatever. Cal the DC and ask for a hard reboot, and it will reboot with your ORIGINAL kernel in place.

[MarlboroMan]

Check the current running kernel with
uname -a
Check both config files - see which one (LILO or GRUB) has the correct kernel listed as default boot. If BOTH do - screw it. Run lilo -v, then tell the customer they use LILO.

[Perlboy]

Hey there,

To identify if you're using lilo or grub.

1) dd if=/dev/hda of=/tmp/boot.img bs=512 count=1
2) cat /tmp/boot.img

It's lilo if it has something about "Missing io.sys". It's GRUB if it mentions GRUB.

Stuart