Introduction to GRUB for Linux

Features of Grub

1. Provide a choice of kernel or System 2 to boot. Provides an interactive interface. Enter GRUB after pressing the E key to enter the interface of grub, can already line Linux system Operation Basic Choice. 3. Password-based protection: Enable kernel image, pass parameter 12341234

Interface format for GRUB

Title: The kernel of the operating system or the header of the system root: Sets the kernel file partition of grub and kernel: Define the kernel file to use, and then attach the parameters passed to the kernel INITRD: Specify the additional drivers provided by the kernel and other functions 12341234

Grub configuration file format

default=0       //Specifies the default boot kernel or boot timeout=5        //waits for the user to select the kernel length, the default unit is seconds splashimage= (hd0,0)/grub/splash.xpm.gz      // Images used at startup hiddenmenu      //hidden menu title centos  (2.6.32-696.6.3.el6.x86_64)     //System kernel name         root  (hd0,0)                    //the partition where the kernel resides         kernel /vmlinuz-2.6.32-696.6.3.el6.x86_64 ro  Root=uuid=9b571efa-58dc-46c5-add3-871cf8abf3c0 rd_no_luks  keyboardtype=pc keytable=us  rd_no_md crashkernel=auto lang=zh_cn. utf-8 rd_no_lvm rd_no_dm rhgb quiet         / /kernel file and pass parameter         initrd /initramfs-2.6 to the kernel.32-696.6.3.el6.x86_64.img1234567812345678 

make a simple kernel
Create another kernel on a system that already has a kernel

 1.  Create the boot and sysroot directories under/mnt     [[email protected] mnt]# mkdir  boot sysroot 2.  partition two partitions on the disk and format them separately for/mnt/boot and/mnt/sysroot     [[email  protected] mnt]# fdisk /dev/sda    WARNING: DOS-compatible  Mode is deprecated. it ' s strongly recommended to switch off the  mode  (command  ' C ')  and change display units to sectors  ( command  ' u ') .    command  (m for help): N    first  cylinder  (4361-7833, default 4361): using default value 4361     last cylinder, +cylinders or +size{k,m,g} (4361-7833, default  7833): +500m    command  (m for help): n     first cylinder  (4426-7833, default 4426):  using default value 4426    last  cylinder, +cylinders or +size{K,M,G}  (4426-7833, default 7833):  +500m     Command  (M FOR HELP): w    [[email protected]  MNT] #kpartx  -af /dev/sda    [[email protected] mnt] #partx  - A /DEV/SDA    [[EMAIL PROTECTED] MNT] #mke2fs  -t eth4 /dev/ SDA7    [[EMAIL PROTECTED] MNT] #mke2fs  -T eth4 /dev/sda8     [[EMAIL PROTECTED] MNT] #mount  /dev/sda7 /mnt/boot     [[EMAIL PROTECTED] MNT] #mount  /dev/sda8 /mnt/sysroot 3.  production grub     [[EMAIL PROTECTED] MNT] #grub-install --root-directory=/mnt   /dev/ sda7    //Note that the disk file here is mounted under/mnt/boot disk  4.  copy kernel file     [[email protected] boot]#  cp /boot/vmlinuz-2.6.32-696.6.3.el6.x86_64 /boot/initramfs-2.6.32-696.6.3.el6.x86_64.img  /mnt/boot/ 5.  Create the root file system of the target machine     [[EMAIL PROTECTED] ]# MKDIR -PV  /mnt/sysroot/{dev,boot,root,home,etc/rc.d,urs,lib,bin,sbin,lib64,mnt,proc,var,medis,sys} 6.  Copy bash and root file system     [[email protected] ] #cp  /bin/bash /mnt/sysroot/bin  7.  Configure GRUB Profiles      vim /mnt/boot/grub/grub.conf      default=0       timeout=5        title         root (hd0,0)       kernel /vmlinuz ro root=/dev/sda1 selinux=0 init=/bin/bash      initramfs /initramfs

This article is from the "Lnsanellinux" blog, make sure to keep this source http://lnsane784.blog.51cto.com/1226518/1948699

Introduction to GRUB for Linux