裁剪RHEL 5.x和RHEL 6.x

写在前面，这篇博文只能让裁剪的系统能够使用简单的bash命令

在裁剪系统之前，先了解能启动系统时，所必需的文件和程序。

1、开机所必需的的bootloader(grub)

2、内核文件、内核镜像文件

3、能执行/sbin/init、有一个能执行命令的bash环境

4、能执行命令时所需的库文件

5、有inittab文件、rc.sysinit执行脚本文件

RHEL 5.x的裁剪

   先添加一块硬盘，把裁剪的系统放到新添加的硬盘上，然后用这块新添加的硬盘当启动盘，能够实现裁剪系统的正常启动，则表示裁剪成功。本实验是用vmworkstation虚拟机完成的。

1）添加硬盘，分两个区，一个boot，一个根文件(rootfs)

         添加硬盘步骤：VM--->Settings--->Add--->Hard Disk--->next--->Create a new virtual disk--->next---SCSI--->next--->

添加磁盘后重启电脑，然后对磁盘分区。

[root@localhost ~]# fdisk /dev/sdb
Command (m for help): n
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 or +size or +sizeM or +sizeK (1-2610, default 2610): +30M
Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 2
First cylinder (6-2610, default 6):
Using default value 6
Last cylinder or +size or +sizeM or +sizeK (6-2610, default 2610): +200M
Command (m for help): w
[root@localhost ~]#partprobe
[root@localhost ~]#mkfs -t ext3 /dev/sdb1 &>/dev/null
[root@localhost ~]#mkfs -t ext3 /dev/sdb2 &>/dev/null

2)为新添加的磁盘的第一个分区创建grub文件

3）copy内核文件和生成内核镜像文件

[root@localhost opt]# pwd
/opt
[root@localhost opt]#find  . | cpio -H newc --quiet -o |gzip -9 > /mnt/boot/initrd.gz   #把opt目录的所有文件利用cpio打包，然后用gzip命令压缩后，输出到/mnt/boot目录下，文件名为initrd.gz

4）复制init和bash等其它命令以及命令的库文件到新添加硬盘的sysroot目录

思路：复制命令时，命令如果要执行，需要依赖该命令所需的库文件，所有在复制命令时，必须把命令依赖的库文件也复制到相应的目录，init的命令位于/sbin/init，库文件位于/lib64(系统为x86_64)下，要将/sbin/init 复制到新硬盘的/mnt/sysroot/sbin目录下，init所依赖的库，也应该复制/mnt/sysroot/lib64目录下

#!/bin/bash
DestDir=/mnt/sysroot
bincp() {
  [ -d ${DestDir}${CmdDir} ] || mkdir -p ${DestDir}${CmdDir}
  [ ! -f ${DestDir}${Cmd} ] && cp $Cmd ${DestDir}${Cmd} && echo "copy $Cmd command to $DestDir finished."
}
libcp() {
  for Lib in `ldd $Cmd | grep -o "[^[:space:]]*/lib[^[:space:]]*"`;do
    LibDir=${Lib%/*}
  [ -d ${DestDir}${LibDir} ] || mkdir -p ${DestDir}${LibDir}
  [ ! -f ${DestDir}${Lib} ] && cp $Lib ${DestDir}${Lib} && echo "copy $Lib  to $DestDir finished."
done
}
read -p "input a command:" Cmd
while [ $Cmd != 'q' -a $Cmd != 'Q' ];do
Cmd=`which $Cmd | grep -v "alias" | sed 's@[[:space:]]@@g'`
CmdDir=${Cmd%/*}
bincp
libcp
read -p "input a command:" Cmd
done
printf "=======Copy command is OK=========\n"

脚本的内容

5)建立系统所需的文件和脚本  grub配置文件、inittab文件和rc.sysinit脚本文件

#grub配置文件
cat >> /mnt/boot/grub/grub.conf <> /mnt/sysroot/etc/inittab << EOF
id:3:initdefault:
si::sysinit:/etc/rc.d/rc.sysinit
EOF
#rc.sysinit脚本文件，/bin/bash，表示开机自动运行bash，生成一个bash环境
cat >> /mnt/sysroot/etc/rc.d/rc.sysinit < 
  
把系统关机，然后把新添加的硬盘作为一个裁剪的系统看能否启动
 
  

 
  
在虚拟机里面新建一个虚拟机，安装之前裁剪的系统，看是否能正常运行
 
  
 
  

 
  
 
  
 
  
 
  
RHEL 5.x的裁剪的脚本，该脚本能自动化的完成上述的操作
 
  
 
  
#!/bin/bash
echo -e "\033[31m=======Frist:Formatting a disk partition======\033[0m"
echo "Inital a disk..."
echo -e "\033[31m Warning:\033[0m"
fdisk -l 2>/dev/null | grep -o "^Disk /dev/[sh]d[a-z]"
read -p "Pls choice a disk:" DiskPart
if [ "$DiskPart" == 'quit' ];then
   echo "you choice quit."
   exit 3
fi
until fdisk -l 2>/dev/null | grep -o "^Disk /dev/[sh]d[a-z]" | grep "^Disk $DiskPart"&>/dev/null ;do
   read -p "you choice is wrong,choice again:" DiskPart
done
read -p "Your choice will destory all data,continue:" Choice
until [ $Choice == 'y' -o $Choice == 'n' ];do
  read -p "Your choice will destory all data,continue:" Choice
done
if [ $Choice == 'n' ];then
   echo "you Choice quit."
   exit 4
else
  dd if=/dev/zero of=$DiskPart bs=512 count=1  &>/dev/null
  sync
  sync
  sleep 3
echo 'n
p
1  #后面有一行空格
+30M
n
p
2  #后面有一行空格
+200M
w'| fdisk $DiskPart &>/dev/null
fi
partprobe
mkfs -t ext3 ${DiskPart}1 &>/dev/null
mkfs -t ext3 ${DiskPart}2 &>/dev/null
printf "===============Partition is OK=========\n"  #以上是分区的脚本
echo -e "\033[31m=======Second:Mount the Partition======\033[0m"
[ -d /mnt/boot ] || mkdir -p /mnt/boot
[ -d /mnt/sysroot ] || mkdir -p /mnt/sysroot
if mount | grep "/dev/sdb1" &>/dev/null;then
  echo "/dev/sdb1 is mounted..."
else
   mount /dev/sdb1   /mnt/boot
fi
if mount | grep "/dev/sdb2" &>/dev/null;then
   echo "/dev/sdb2 is mounted...."
else 
  mount /dev/sdb2  /mnt/sysroot
fi
printf "===============Mount is OK=========\n"
echo -e "\033[31m=======Third: Create boot partition======\033[0m"
[ -d /mnt/boot/grub ]|| grub-install --root-directory=/mnt   /dev/sdb &>/dev/null;echo "grub is ok"
printf "========Boot partition is OK============\n"
echo -e "\033[31m=======Fourth:Copy the kernel and make the kernel p_w_picpath file======\033[0m"
cp /boot/vmlinuz-2.6.18-308.el5    /mnt/boot/vmlinuz
rm -rf /opt/*
cd /opt
mkinitrd /opt/initrd-`uname -r`.img  `uname -r`
zcat /opt/initrd-`uname -r`.img | cpio -id  &>/dev/null
rm -rf /opt/initrd-`uname -r`.img
sed -i '/resume/s@resume@#resume@g' /opt/init  #把resume那行的前面添加#，即注释掉resume开头的行
sed -i 's/mkrootdev/# &/'  /opt/init    #先把mkrootdev开头的行注释
sed -i '/mkrootdev/a\mkrootdev -t ext3 -o defaults,ro /dev/sda2' /opt/init      #然后在mkrootdev那行下面添加一行mkrootdev -t ext3 -o defaults,ro /dev/sda2
find  . | cpio -H newc --quiet -o |gzip -9 > /mnt/boot/initrd.gz
printf "========Kernel and kernel p_w_picpath file is OK========\n"
echo -e "\033[31m=======Fifth:Edit grub configuration file======\033[0m"
cat >> /mnt/boot/grub/grub.conf <> /mnt/sysroot/etc/inittab << EOF
id:3:initdefault:
si::sysinit:/etc/rc.d/rc.sysinit
EOF
cat >> /mnt/sysroot/etc/rc.d/rc.sysinit < 
  
运行脚本的过程
 
  
 
  

 
  

 
  
RHEL 6.x系统的裁剪步骤就详细描述了，直接写脚本
 
  
#!/bin/bash
echo -e "\033[31m=======Frist:Formatting a disk partition======\033[0m"
echo "Inital a disk..."
echo -e "\033[31m Warning:\033[0m"
fdisk -l 2>/dev/null | grep -o "^Disk /dev/[sh]d[a-z]"
read -p "Pls choice a disk:" DiskPart
if [ "$DiskPart" == 'quit' ];then
   echo "you choice quit."
   exit 3
fi
until fdisk -l 2>/dev/null | grep -o "^Disk /dev/[sh]d[a-z]" | grep "^Disk $DiskPart"&>/dev/null ;do
   read -p "you choice is wrong,choice again:" DiskPart
done
read -p "Your choice will destory all data,continue:" Choice
until [ $Choice == 'y' -o $Choice == 'n' ];do
  read -p "Your choice will destory all data,continue:" Choice
done
if [ $Choice == 'n' ];then
   echo "you Choice quit."
   exit 4
else
  dd if=/dev/zero of=$DiskPart bs=512 count=1  &>/dev/null
  sync
  sync
  sleep 3
echo 'n
p
1
+30M
n
p
2
+200M
w'| fdisk $DiskPart &>/dev/null
fi
partx -a ${DiskPart}1 $DiskPart
partx -a ${DiskPart}2 $DiskPart
mkfs -t ext4 ${DiskPart}1 &>/dev/null
mkfs -t ext4 ${DiskPart}2 &>/dev/null
printf "===============Partition is OK=========\n"
echo -e "\033[31m=======Second:Mount the Partition======\033[0m"
[ -d /mnt/boot ] || mkdir -p /mnt/boot
[ -d /mnt/sysroot ] || mkdir -p /mnt/sysroot
if mount | grep "/dev/sdb1" &>/dev/null;then
  echo "/dev/sdb1 is mounted..."
else
   mount /dev/sdb1   /mnt/boot
fi
if mount | grep "/dev/sdb2" &>/dev/null;then
   echo "/dev/sdb2 is mounted...."
else 
  mount /dev/sdb2  /mnt/sysroot
fi
printf "===============Mount is OK=========\n"
echo -e "\033[31m=======Third: Create boot partition======\033[0m"
[ -d /mnt/boot/grub ]|| grub-install --root-directory=/mnt   /dev/sdb &>/dev/null;echo "grub is ok"
printf "========Boot partition is OK============\n"
echo -e "\033[31m=======Fourth:Copy the kernel and make the kernel p_w_picpath file======\033[0m"
cp /boot/vmlinuz-2.6.32-358.el6.x86_64   /mnt/boot/vmlinuz
mkinitrd /opt/initramfs-`uname -r`.img  `uname -r`
cp /opt/initramfs-2.6.32-358.el6.x86_64.img  /mnt/boot/initrd.gz
printf "========Kernel and kernel p_w_picpath file is OK========\n"
echo -e "\033[31m=======Fifth:Edit grub configuration file======\033[0m"
cat >> /mnt/boot/grub/grub.conf <> /mnt/sysroot/etc/inittab << EOF
id:3:initdefault:
EOF
cat >> /mnt/sysroot/etc/rc.d/rc.sysinit <