[Linux-users] Grub options menu on CentOS

[Lonni J Friedman]

On 8/21/07, Bill Campbell <linux-sxs at celestial.com> wrote:
> On Tue, Aug 21, 2007, C M Reinehr wrote:
> >Bill,
> >
> >On Tuesday 21 August 2007 13:09, Bill Campbell wrote:
> >> I'm gradually learning my way around CentOS systems, but haven't figured
> >> out how to select different init states from grub.
> >>
> >> On the SuSE systems I've been using, one can type ``init 3'' at the grub
> >> prompt, but CentOS doeesn't provide that prompt.  When I've gone into the
> >> grub edit mode, and attempted to set it there, I haven't found the correct
> >> incantation to select different init states (I assume init=/bin/sh would
> >> work, but that's generally useful only in serious emergencies).
> >>
> >> I've compared the /boot/grub/menu.lst files on SuSE and CentOS, but don't
> >> see anything that looks like it would control this, and the ``info'' pages
> >> are, as usual, don't seem to go into any useful detail.
> >>
> >> How does one configure grub to provide the options prompt where one can
> >> specify boot options?
> >>
> >> Bill
> >
> >It appears that the answer to your question is in the init manual, rather
> >than the grub manual. I'm familiar with editing the grub/menu.lst to boot
> >into single user mode, but I had to do a little research to see what other
> >possibilities exist. These are lines from my menu.lst file.
> >
> >This will boot into the default init state as defined in /etc/inittab:
> >kernel /vmlinuz-2.6.18-custom.5 root=/dev/mapper/vg0-lv_root ro vga=0x314
> >
> >This will boot into single user mode:
> >kernel /vmlinuz-2.6.18-custom.5 root=/dev/mapper/vg0-lv_root ro vga=0x314 single
> >
> >Presumably, if I understand the entry in man:init/Bootflags, you could boot into
> >init mode 3 by replacing the word single with 3.
> >
> >You could have as many boot stanzas in menu.lst as you had run levels defined
> >in /etc/inittab. Of course, if you wanted to boot always into run level three
> >then you should just edit inittab & define your default run level.
>
> I understand how to edit each grep entry using ``e'', ``b'', etc., but my
> question was how to get the grub option prompt at the initial menu where
> one can type options for the selected boot line without having to deal with
> that rather clunky interface.

that's not possible in RHEL.  Its a SUSE 'feechur', which is usually
the first thing I disable, as I hate it.

>
> On a SuSE system, I can simply type ``init 3'', ``init 5'', ``acpi=off'',
> or whatever without having to get into edit mode.  I hate to think what a
> customer could do to a system if I'm trying to explain how to edit over the
> phone.

Then create a new entry in their grub config for the different
runlevels, and then you just need to tell them to select whichever one
they prefer/need.