系统初始化

系统初始化

查看 uname –r

操作系统版本号 cat /etc/redhat-release

查看主机名uname -n

查看平台 uname -p

进入 boot下执行ll命令得到

第四行为所需加载的驱动最后一行为虚拟内核

服务***************************************

chkconfig –list 查看服务

chkconfig --list |grep sendmail 查看邮件服务

rpm -e服务名，卸载服务

rpm –q --scriptes httpd ，显示动作

chkconfig --level 3（级别） sendmail(服务) off（状态）

setup只能设置当前的级别

ntsysv

service httpd （服务） start（动作，stoprestart）

/etc/init.d/服务动作

服务分两类独立（存放于/etc/init.d/）依赖于超级守护进程（存放于 /etc/xinetd.d）

防火墙以及selinux影响服务的执行

Init /etc/inittab 充电自检

开机自检（BIOS）》》MBR引导（512字节）》》GRUB菜单》》加载内核（kernel）》》运行INIT进程》》读取/etc/inittab配置文件，》》执行/etc/rc.d/rc.sysinit脚本

| i 》》执行/etc/rc.d/rc脚本

执行/etc/c.d/rc.local |

启动mingetty进程

进入grub ，cd /boot/grub 查看 ll

grub-install /dev/sda 导入

grub-install –root-directory=/ /dev/sda 导入

vim /etc/grub.conf 查看配置脚本

[root@localhost ~]# vim /etc/grub.conf

# grub.conf generated by anaconda

# Note that you do not have to rerun grub after making changes to this file

# NOTICE: You have a /boot partition. This means that

# all kernel and initrd paths are relative to /boot/, eg.

# root (hd0,0)

# kernel /vmlinuz-version ro root=/dev/sda2

# initrd /initrd-version.img

#boot=/dev/sda 所在硬盘

default=0 对应操作系统

timeout=5 等待时间过后5秒后自动选择

splashp_w_picpath=(hd0,0)/grub/splash.xpm.gz grub的背景图片

hiddenmenu 隐藏grub菜单

title Red Hat Enterprise Linux Server (2.6.18-164.el5) title为标签

ro ot (hd0,0) 引导分区根

kernel /vmlinuz-2.6.18-164.el5 ro root=LABEL=/ rhgb quiet 内核为kernel

initrd /initrd-2.6.18-164.el5.img驱动程序

[root@localhost ~]# findfs LABEL=/ 查找标签为 / 的所在

/dev/sda2

-rw------- 1 root root 2602240 02-21 15:10 initrd-2.6.18-164.el5.img

[root@localhost abc]# zcat initrd-2.6.18-164.el5.img |cpio –id 解压驱动包

11611 blocks

[root@localhost abc]# ll

?昏. 2580

drwx------ 2 root root 4096 02-21 15:15 bin

drwx------ 3 root root 4096 02-21 15:15 dev

drwx------ 2 root root 4096 02-21 15:15 etc

-rwx------ 1 root root 2536 02-21 15:15 init

-rw------- 1 root root 2602240 02-21 15:10 initrd-2.6.18-164.el5.img

drwx------ 3 root root 4096 02-21 15:15 lib

drwx------ 2 root root 4096 02-21 15:15 proc

lrwxrwxrwx 1 root root 3 02-21 15:15 sbin -> bin

drwx------ 2 root root 4096 02-21 15:15 sys

drwx------ 2 root root 4096 02-21 15:15 sysroot

[root@localhost abc]# vim /etc/inittab 进入初始化表

1 #

2 # inittab This file describes how the INIT process should set up

3 # the system in a certain run-level.

4 #

5 # Author: Miquel van Smoorenburg, <[email protected]>

6 # Modified for RHS Linux by Marc Ewing and Donnie Barnes

7 #

9 # Default runlevel. The runlevels used by RHS are:

10 # 0 - halt (Do NOT set initdefault to this)

11 # 1 - Single user mode

13 # 3 - Full multiuser mode

14 # 4 - unused

15 # 5 - X11

16 # 6 - reboot (Do NOT set initdefault to this)

17 #

18 id:3:initdefault:

20 # System initialization.

21 si::sysinit:/etc/rc.d/rc.sysinit 进入级别前所需执行的脚本（初始化脚本）

23 l0:0:wait:/etc/rc.d/rc 0

24 l1:1:wait:/etc/rc.d/rc 1

25 l2:2:wait:/etc/rc.d/rc 2

26 l3:3:wait:/etc/rc.d/rc 3

27 l4:4:wait:/etc/rc.d/rc 4

28 l5:5:wait:/etc/rc.d/rc 5

29 l6:6:wait:/etc/rc.d/rc 6

31 # Trap CTRL-ALT-DELETE

32 ca::ctrlaltdel:/sbin/shutdown -t3 -r now 条件满足可重启

34 # When our UPS tells us power has failed, assume we have a few minutes

35 # of power left. Schedule a shutdown for 2 minutes from now.

36 # This does, of course, assume you have powerd installed and your

37 # UPS connected and working correctly. UPS备用电源

38 pf::powerfail:/sbin/shutdown -f -h +2 "Power Failure; System Shutting Down"

39 电源失效执行动作 –f快速启动

40 # If power was restored before the shutdown kicked in, cancel it.

41 pr:12345:powerokwait:/sbin/shutdown -c "Power Restored; Shutdown Cancelled"

42 来电了取消shutdown

44 # Run gettys in standard runlevels

45 1:2345:respawn:/sbin/mingetty tty1 （2345代表级别启动sbin/mingetty tty终端）

46 2:2345:respawn:/sbin/mingetty tty2 （respawn动作注销亦执行）

47 3:2345:respawn:/sbin/mingetty tty3

48 4:2345:respawn:/sbin/mingetty tty4

49 5:2345:respawn:/sbin/mingetty tty5

50 6:2345:respawn:/sbin/mingetty tty6

52 # Run xdm in runlevel 5

53 x:5:respawn:/etc/X11/prefdm –nodaemon进5级别所需执行的脚本

[root@localhost abc]# file /etc/rc.d/rc.sysinit 查询其脚本类型

/etc/rc.d/rc.sysinit: Bourne-Again shell script text executable 可执行bash脚本

[root@localhost abc]# vim /etc/rc.d/rc.sysinit 查看脚本内容

#!/bin/bash

# /etc/rc.d/rc.sysinit - run once at boot time

# Taken in part from Miquel van Smoorenburg's bcheckrc.

HOSTNAME=`/bin/hostname`

HOSTTYPE=`uname -m`

unamer=`uname -r`

set -m

if [ -f /etc/sysconfig/network ]; then

. /etc/sysconfig/network

if [ -z "$HOSTNAME" -o "$HOSTNAME" = "(none)" ]; then

HOSTNAME=localhost

if [ ! -e /proc/mounts ]; then

mount -n -t proc /proc /proc

mount -n -t sysfs /sys /sys >/dev/null 2>&1

"/etc/rc.d/rc.sysinit" 980L, 27239C

故障排除
事例1 模拟grub损坏
[root@localhost rc3.d]# dd if=/dev/zero of=/dev/sda bs=446 count=1
1+0 records in
1+0 records out
446 bytes (446 B) copied, 0.000131491 seconds, 3.4 MB/s
执行后发现正常启动不了

执行Linux rescue 紧急救援模式
进入sysp_w_picpath下 cd /mnt/sysp_w_picpath
Chroot /mnt/sysp_w_picpath
Grub-install /dev/sda
Exit
Exit
系统将会重启完毕
事例2
删除boot/grub/下面的grub.conf
[root@localhost ~]# mv /boot/grub/grub.conf /boot/grub/grub.conf.old 改动grub.conf名=删除
重新启动后如下所示
进入grub下，执行如下命令，分别实现找硬盘，加载内核，加载驱动，然后 boot重启，

重启后记得要将/boot/grub下的grub.conf恢复或者手工编辑