引导加载程序grub的使用详解

引导加载程序grub的使用详解

• 为运行于虚拟机上的CentOS 6添加一个新硬件，提供两个主分区

  • 为硬盘建两个主分区；并为其安装grub
  • 为硬盘的第一个主分区提供内核和ramdisk文件；为第二个分区提供rootfs
  • 为rootfs提供bash、ls、cat程序以及所依赖的库文件
  • 为grub提供配置文件

  • 将新的硬盘设置为第一启动项并能够正常启动目标主机

    • 1.新建分区

        [root@slave1 ~]# fdisk /dev/sdb
         Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
         Building a new DOS disklabel with disk identifier 0xf614f379.
         Changes will remain in memory only, until you decide to write them.
         After that, of course, the previous content won't be recoverable.
      
         Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
      
         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
         Command action
            e   extended
            p   primary partition (1-4)
         1
         Invalid partition number for type `1'
         Command action
            e   extended
            p   primary partition (1-4)
         p
         Partition number (1-4): 1
         First cylinder (1-2610, default 1):
         Using default value 1
         Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610): +5G
      
         Command (m for help): n
         Command action
            e   extended
            p   primary partition (1-4)
         p
         Partition number (1-4): 2
         First cylinder (655-2610, default 655):
         Using default value 655
         Last cylinder, +cylinders or +size{K,M,G} (655-2610, default 2610): +5G
      
         Command (m for help): w
         The partition table has been altered!
      
         Calling ioctl() to re-read partition table.
         Syncing disks.
         [root@slave1 ~]# fdisk -l
      
         Disk /dev/sda: 21.5 GB, 21474836480 bytes
         255 heads, 63 sectors/track, 2610 cylinders
         Units = cylinders of 16065 * 512 = 8225280 bytes
         Sector size (logical/physical): 512 bytes / 512 bytes
         I/O size (minimum/optimal): 512 bytes / 512 bytes
         Disk identifier: 0x00026a25
      
            Device Boot      Start         End      Blocks   Id  System
         /dev/sda1   *           1          64      512000   83  Linux
         Partition 1 does not end on cylinder boundary.
         /dev/sda2              64        2611    20458496   8e  Linux LVM
      
         Disk /dev/sdb: 21.5 GB, 21474836480 bytes
         255 heads, 63 sectors/track, 2610 cylinders
         Units = cylinders of 16065 * 512 = 8225280 bytes
         Sector size (logical/physical): 512 bytes / 512 bytes
         I/O size (minimum/optimal): 512 bytes / 512 bytes
         Disk identifier: 0xf614f379
      
            Device Boot      Start         End      Blocks   Id  System
         /dev/sdb1               1         654     5253223+  83  Linux
         /dev/sdb2             655        1308     5253255   83  Linux
      
         Disk /dev/mapper/vg_slave1-lv_root: 18.9 GB, 18865979392 bytes
         255 heads, 63 sectors/track, 2293 cylinders
         Units = cylinders of 16065 * 512 = 8225280 bytes
         Sector size (logical/physical): 512 bytes / 512 bytes
         I/O size (minimum/optimal): 512 bytes / 512 bytes
         Disk identifier: 0x00000000
      
         Disk /dev/mapper/vg_slave1-lv_swap: 2080 MB, 2080374784 bytes
         255 heads, 63 sectors/track, 252 cylinders
         Units = cylinders of 16065 * 512 = 8225280 bytes
         Sector size (logical/physical): 512 bytes / 512 bytes
         I/O size (minimum/optimal): 512 bytes / 512 bytes
         Disk identifier: 0x00000000

    • 2.挂载boot和根文件系统

         [root@slave1 ~]# mke2fs -t ext4 /dev/sdb1
         [root@slave1 ~]# mke2fs -t ext4 /dev/sdb2
         [root@slave1 ~]# mkdir /myroot
         [root@slave1 ~]# mkdir /myroot/boot
         [root@slave1 ~]# mount /dev/sdb2 /myroot/boot
         [root@slave1 ~]# mkdir /myroot/sysroot
         [root@slave1 ~]# mount /dev/sdb1 /myroot/sysroot
         [root@slave1 myroot]# vi /etc/fstab
         /dev/sdb1               /myroot/sysroot                ext4     defaults        1 1
         /dev/sdb2               /myroot/boot           ext4     defaults        1 2

    • 3.安装配置grub

         [root@slave1 /]# grub-install --root-directory=/myroot /dev/sdb
         [root@slave1 boot]# cp /boot/vmlinuz-2.6.32-431.el6.x86_64 /myroot/boot/
         [root@slave1 boot]# cp /boot/initramfs-2.6.32-431.el6.x86_64.img /myroot/boot/
         [root@slave1 grub]# vim /myroot/boot/grub/grub.conf
          default=0
          timeout=5
          title centos6.5 simple
             root (hd1,1)
             kernel /vmlinuz-2.6.32-431.el6.x86_64 ro root=/dev/sdb1 selinux=0 init=/bin/bash
             initrd /initramfs-2.6.32-431.el6.x86_64.img

    • 4.创建根文件系统

         [root@slave1 myroot]# mkdir etc bin sbin lib lib64 usr home root sys proc var mnt media
         [root@slave1 myroot]# cp /bin/{bash,ls,cat} /myroot/bin/
         [root@slave1 bin]# ldd bash
                 linux-vdso.so.1 =>  (0x00007fffc5f45000)
                 libtinfo.so.5 => /lib64/libtinfo.so.5 (0x00007f0fbe3f8000)
                 libdl.so.2 => /lib64/libdl.so.2 (0x00007f0fbe1f4000)
                 libc.so.6 => /lib64/libc.so.6 (0x00007f0fbde5f000)
                 /lib64/ld-linux-x86-64.so.2 (0x00007f0fbe622000)
         [root@slave1 bin]# cp  /lib64/{libtinfo.so.5,libdl.so.2,libc.so.6,ld-linux-x86-64.so.2}  /myroot/lib64/
         [root@slave1 bin]# ldd ls
                 linux-vdso.so.1 =>  (0x00007fff6adfe000)
                 libselinux.so.1 => /lib64/libselinux.so.1 (0x00007fd0f7832000)
                 librt.so.1 => /lib64/librt.so.1 (0x00007fd0f762a000)
                 libcap.so.2 => /lib64/libcap.so.2 (0x00007fd0f7425000)
                 libacl.so.1 => /lib64/libacl.so.1 (0x00007fd0f721d000)
                 libc.so.6 => /lib64/libc.so.6 (0x00007fd0f6e89000)
                 libdl.so.2 => /lib64/libdl.so.2 (0x00007fd0f6c84000)
                 /lib64/ld-linux-x86-64.so.2 (0x00007fd0f7a5a000)
                 libpthread.so.0 => /lib64/libpthread.so.0 (0x00007fd0f6a67000)
                 libattr.so.1 => /lib64/libattr.so.1 (0x00007fd0f6862000)
         [root@slave1 bin]# cp /lib64/ {libselinux.so.1,librt.so.1,libcap.so.2,libacl.so.1,libc.so.6,libdl.so.2,ld-linux-x86-64.so.2,libpthread.so.0,libattr.so.1} /myroot/lib64/   
           cp: overwrite `/myroot/lib64/libc.so.6'? no
           cp: overwrite `/myroot/lib64/libdl.so.2'? no
           cp: overwrite `/myroot/lib64/ld-linux-x86-64.so.2'? no
         [root@slave1 bin]# ldd cat
                 linux-vdso.so.1 =>  (0x00007fff749e7000)
                 libc.so.6 => /lib64/libc.so.6 (0x00007f6bdc516000)
                 /lib64/ld-linux-x86-64.so.2 (0x00007f6bdc8b3000)
         [root@slave1 bin]# cp  /lib64/{libc.so.6,ld-linux-x86-64.so.2} /myroot/lib64/
           cp: overwrite `/myroot/lib64/libc.so.6'? no
           cp: overwrite `/myroot/lib64/ld-linux-x86-64.so.2'? no

    • 5.更改启动项

      • 点击菜单栏的虚拟机选项，下拉菜单里点击电源，电源选项里选择打开电源时进入固件，进入BIOS设置界面，选择boot菜单里的VMware Virtual SCSI Hard Drive(0:1)将新的硬盘设置为第一启动项，保存