Ubuntu 14.04 – How to Set Default Runlevel

Theoretically, if Ubuntu were compliant with UNIX and Linux standard, adding '3' to grub's 'kernel' command in /boot/grub/menu.lst should have been sufficient, because runlevel '3' means no 'X11' according to this standard.

Unfortunately, Ubuntu has ignored the standard and that's why you'll need to change /etc/init/lightdm.conf or /etc/init/gdm.conf (or whatever DM you use) as well. This is how mine "on start" condition looks like:

start on ((filesystem
       and runlevel [!06]
       and runlevel [!03]
       and started dbus
       and plymouth-ready)
      or runlevel PREVLEVEL=S)

In Grub's menu.lst I've also added a menu item that allows me to boot to runlevel 3:

title           Ubuntu 11.10 Server No UI, kernel 3.0.0-32-generic-pae
root            (hd0,0)
kernel          /vmlinuz-3.0.0-32-generic-pae root=UUID=your-root-disk-id 3 ro
initrd          /initrd.img-3.0.0-32-generic-pae
quiet


title           Ubuntu 11.10, kernel 3.0.0-32-generic-pae
root            (hd0,0)
kernel          /vmlinuz-3.0.0-32-generic-pae root=your-root-disk-id ro
initrd          /initrd.img-3.0.0-32-generic-pae
quiet

Now I can chose between booting to runlevel 5 with X11 or to runlevel 3 without it.

The problem with adding an entry using 40_custom is that the entry is static - the contents are copied as-is to grub.cfg, so a new kernel requires re-editing that file. With very slight tinkering of the 10-linux, you can get update-grub to generate an additional entry for each of the installed kernels. Edit /etc/grub.d/10_linux, and after the lines where it says:

linux_entry "${OS}" "${version}" advanced \
            "${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT}"
if [ "x${GRUB_DISABLE_RECOVERY}" != "xtrue" ]; then
  linux_entry "${OS}" "${version}" recovery \
              "${GRUB_CMDLINE_LINUX_RECOVERY} ${GRUB_CMDLINE_LINUX}"
fi

Add another call to linux_entry:

linux_entry "${OS}, runlevel 3" "${version}" advanced \
          "${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT} 3"

(Selecting a runlevel is as simple as tacking on the number at the end of the options, IIRC.)

Effect:

Menu entry in the "Advanced options" sub menu:
The contents of that entry:

Of course, normally runlevels 2-5 are equivalent, so booting from it made no difference to me, except:

$ runlevel
N 3