centos ubuntu 双系统引导的grub设置

今天没事安装了一个CENTOS和ubuntu,先安装的centos后安装的ubuntu，安装完ubuntu后发现grub启动菜单里没有
centos的选项，后在google.com中查到了如果利用centos来引导ubuntu的方法，把我操作的过程记录下来，方便以后查找．

１,先安装centos,再安装ubuntu.

2,用centos安装盘启动，在出现启动选项的时候用linux rescue

在shell下执行
chroot /mnt/sysimage

grub-install /dev/sda

修复centos的grub,然后reboot

3.进入centos

挂接ubuntu的分区

mount /dev/sda6 /media

vi /media/boot/grub/grub.cfg
#

# DO NOT EDIT THIS FILE

#

# It is automatically generated by /usr/sbin/grub-mkconfig using
templates

# from /etc/grub.d and settings from /etc/default/grub

#

### BEGIN /etc/grub.d/00_header ###

if [ -s /boot/grub/grubenv ]; then

  have_grubenv=true

  load_env

fi

set default="0"

if [ ${prev_saved_entry} ]; then

  saved_entry=${prev_saved_entry}

  save_env saved_entry

  prev_saved_entry=

  save_env prev_saved_entry

fi

insmod ext2

set root=(hd0,2)

search --no-floppy --fs-uuid --set 1a2b230e-d172-4b48-8395-72a33ebce462

if loadfont /usr/share/grub/unicode.pf2 ; then

  set gfxmode=640x480

  insmod gfxterm

  insmod vbe

  if terminal_output gfxterm ; then true ; else

    # For backward compatibility with versions of terminal.mod that
don't

    # understand terminal_output

    terminal gfxterm

  fi

fi

if [ ${recordfail} = 1 ]; then

  set timeout=-1

else

  set timeout=10

fi

### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/05_debian_theme ###

set menu_color_normal=white/black

set menu_color_highlight=black/white

### END /etc/grub.d/05_debian_theme ###

### BEGIN /etc/grub.d/10_linux ###

menuentry "Ubuntu, Linux 2.6.31-14-generic" {

        recordfail=1

        if [ -n ${have_grubenv} ]; then save_env recordfail; fi

        set quiet=1

        insmod ext2

        set root=(hd0,2)

        search --no-floppy --fs-uuid --set
1a2b230e-d172-4b48-8395-72a33ebce462

        linux   /boot/vmlinuz-2.6.31-14-generic
root=UUID=1a2b230e-d172-4b48-8395-72a33ebce462 ro   quiet splash

        initrd  /boot/initrd.img-2.6.31-14-generic

}

menuentry "Ubuntu, Linux 2.6.31-14-generic (recovery mode)" {

        recordfail=1

        if [ -n ${have_grubenv} ]; then save_env recordfail; fi

        insmod ext2

        set root=(hd0,2)

        search --no-floppy --fs-uuid --set
1a2b230e-d172-4b48-8395-72a33ebce462

        linux   /boot/vmlinuz-2.6.31-14-generic
root=UUID=1a2b230e-d172-4b48-8395-72a33ebce462 ro single

        initrd  /boot/initrd.img-2.6.31-14-generic

}

### END /etc/grub.d/10_linux ###　
　　

复制下面内容并带上uuid

        linux   /boot/vmlinuz-2.6.31-14-generic
root=UUID=1a2b230e-d172-4b48-8395-72a33ebce462 ro   quiet splash

        initrd  /boot/initrd.img-2.6.31-14-generic

编辑centos的grub.conf,把复制的内容加入到grub.conf中,并修改如下所示

vi /boot/grub/grub.conf
title Ubuntu 9.10

        root (hd0,0)

        kernel   /vmlinuz-2.6.31-14-generic
root=UUID=b2a79ba9-abbc-45dd-810d-2052cd782aea ro   quiet splash

        initrd  /initrd.img-2.6.31-14-generic

cp ubuntu 下的vmlinuz 及initrd到centos的boot下面

cp /media/boot/vmlinuz-2.6.31-14-generic /boot/

cp /media/boot/initrd.img-2.6.31-14-generic /boot/