Need to edit grub.conf

shahdharmit · #1 14th August 2009, 08:36 PM

Hello..

I installed CentOS 5.3 in my laptop few hours back and chose not to install boot loader as I already had one in Fedora 11. My Fedora 11 is running perfectly but the issue is that I can't get a option in boot loader to boot CentOS. Can anyone please help me out. Below is the detail for CentOS that I myself wrote in grub.conf:

Quote:

title CentOS
root (hd0,3)
kernel /vmlinuz-2.6.18-128.el5 ro root=/dev/sda4 rhgb quiet
initrd /initrd-2.6.18-128.el5.img

Thanks

sonoran · #2 14th August 2009, 09:52 PM

Have you commented #hiddenmenu and adjusted the timeout to >0?

bbfuller · #3 14th August 2009, 10:45 PM

Hello shahdharmit

I've got CentOS working here as a third OS alongside Windows XP and Debian on the same disk.

I agree with sonoran about the need to edit menu.lst to comment out "hiddenmenu" and make the timeout a setting where you will be able to see the boot menu entries.

In the case of Debian, it automatically detected the CentOS and Windows installations and added them itself to "menu.lst". I do notice though that two of the lines it has entered are different to yours.

Where you have:

Quote:

kernel /vmlinuz-2.6.18-128.el5 ro root=/dev/sda4 rhgb quiet
initrd /initrd-2.6.18-128.el5.img

My "menu.lst" reads:

Code:

kernel /boot/vmlinuz-2.6.18-128.el5 ro root=/dev/sda4 rhgb quiet
initrd /boot/initrd-2.6.18-128.el5.img

I've just tried it without the "/boot" additions to those two lines and it won't start without them.

I accept that Fedora doesn't appear to need those additions but it appears that for CentOS you need to be more explicit about the path.

zackf · #4 14th August 2009, 11:01 PM

Quote:

Originally Posted by shahdharmit

Hello..

I installed CentOS 5.3 in my laptop few hours back and chose not to install boot loader as I already had one in Fedora 11. My Fedora 11 is running perfectly but the issue is that I can't get a option in boot loader to boot CentOS. Can anyone please help me out. Below is the detail for CentOS that I myself wrote in grub.conf:

Thanks

Just add what you have for CentOS to your /etc/grub.conf in F11 and you should be golden.

stoat · #5 14th August 2009, 11:26 PM

Quote:

Originally Posted by bbfuller

I've just tried it without the "/boot" additions to those two lines and it won't start without them.

I accept that Fedora doesn't appear to need those additions but it appears that for CentOS you need to be more explicit about the path.

Hello bbfuller,

When to add /boot in a GRUB terminal command or menu command depends on whether or not there is a separate boot partition. If there is, then do not include /boot in the path. If there is not a separate boot partition, then always include /boot in the path. Therefore, I predict that your CentOS system does not have a separate boot partition. In the commented text of a Fedora grub.conf, it will say that all paths are relative to something. Sometimes it's / and sometimes it's /boot. For example...

Code:

# NOTICE:  You have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,0)
#          kernel /vmlinuz-version ro root=/dev/hda7
#          initrd /initrd-version.img

...or...

Code:

# NOTICE: You do not have a /boot partition. This means that
#          all kernel and initrd paths are relative to /, eg.
#          root (hd0,4)
#          kernel /boot/vmlinuz-version ro root=/dev/sda5
#          initrd /boot/initrd-version.img

Hey, I didn't invent it.

Quote:

Originally Posted by zackf

Just add what you have for CentOS to your /etc/grub.conf in F11 and you should be golden.

Hello zackf,

In the first post, shahdharmit said he/she chose not to install a boot loader intending to use an existing one. That's what that boot loader option is supposed to be for, I guess. But here's the thing. That usually results in no grub.conf or menu.lst being created. No GRUB stages are created. Usually nothing exists in the /boot/grub folder but the splashscreen image. So, copying menu commands is not an option. I don't think people should do that option because it forces them to hand-write menu commands for the existing boot loader's config file, and that's not always so easy to do. Next time shahdharmit wants to install that way, I recommend choosing the option to install the new system's GRUB in the first sector of its boot partition. That doesn't disturb the existing boot loader, but it preserves all the other booting options like configfile, chainloader and copying from the grub.conf because the grub.conf and the stage files are all there as usual.

zackf · #6 15th August 2009, 03:45 AM

Quote:

Originally Posted by stoat

Hello bbfuller,

Hello zackf,

In the first post, shahdharmit said he/she chose not to install a boot loader intending to use an existing one. That's what that boot loader option is supposed to be for, I guess. But here's the thing. That usually results in no grub.conf or menu.lst being created. No GRUB stages are created. Usually nothing exists in the /boot/grub folder but the splashscreen image. So, copying menu commands is not an option. I don't think people should do that option because it forces them to hand-write menu commands for the existing boot loader's config file, and that's not always so easy to do. Next time shahdharmit wants to install that way, I recommend choosing the option to install the new system's GRUB in the first sector of its boot partition. That doesn't disturb the existing boot loader, but it preserves all the other booting options like configfile, chainloader and copying from the grub.conf because the grub.conf and the stage files are all there as usual.

I misunderstood that shahdharmit manually wrote that in his F11 grub instead of taking it out of Cent. After re-reading you're absolutely right.

shahdharmit · #7 15th August 2009, 06:24 AM

sonoran-> As per your advise I've commented out hidden menu but I don't know it's effect is whatsoever.

bbfuller-> We've had talk earlier so you might be knowing that I already have been using F11. And CentOS was installed after that so I didn't quite get you when you mentioned that Deb could easily detect WinXP and CentOS installations. I didn't let CentOS detect my installations at all.

One more thing, I've got a huge list of kernels in grub.conf of F11 due to the updates. Now can I install a boot loader of CentOS and then add /dev/sda5 while installation so that it boots up Fedora?

I might sound idiot but I I couldn't create a /boot partition for CentOS. I tried a heck lot of times but it didn't let me do. It showed up an error that "No space left for None". That confused me. Can I use Fedora's /boot partition somehow to boot CentOS or by installing the CentOS boot loader and adding the entry for Fedora's /boot path in it will do the thing? CentOS is on /dev/sda4 and the boot partition of Fedora is on /dev/sda5.

shahdharmit · #8 15th August 2009, 06:28 AM

I just read stoat's post a bit deeply and I think I've to use /boot of F11 to let CentOS boot. Thanks Stoat.

sonoran · #9 15th August 2009, 07:10 AM

Quote:

Originally Posted by shahdharmit

I just read stoat's post a bit deeply and I think I've to use /boot of F11 to let CentOS boot. Thanks Stoat.

Hello shahdharmit,
Unless I misunderstand you, I do not think that will work. Each OS needs its own /boot directory, whether or not that is located on a separate partition. Can you look at your centOS filesystem, either from Fedora or a rescue disk or livecd, and see what is in the /boot directory?

shahdharmit · #10 15th August 2009, 09:26 AM

sonoran, issue solved. And I figured out the purpose of commenting out hiddenmenu. That was nice. I like it this way. I used the /boot partition of F11 to boot centOS. Just as mentioned some of the posts by other fellow members of the forum. Thanks for your help sonoran. And thanks to bbfuller, stoat and zackf. Thanks a lot guys. Btw, you can address me by "he". :-)