系統初始化

系統初始化

查看 uname –r

操作系統版本號 cat /etc/redhat-release

查看主機名uname -n

查看平臺 uname -p

進入 boot下執行ll命令得到

第四行爲所需加載的驅動最後一行爲虛擬內核

服務***************************************

chkconfig –list 查看服務

chkconfig --list |grep sendmail 查看郵件服務

rpm -e服務名，卸載服務

rpm –q --scriptes httpd ，顯示動作

chkconfig --level 3（級別） sendmail(服務) off（狀態）

setup只能設置當前的級別

ntsysv

service httpd （服務） start（動作，stoprestart）

/etc/init.d/服務動作

服務分兩類獨立（存放於/etc/init.d/）依賴於超級守護進程（存放於 /etc/xinetd.d）

防火牆以及selinux影響服務的執行

Init /etc/inittab 充電自檢

開機自檢（BIOS）》》MBR引導（512字節）》》GRUB菜單》》加載內核（kernel）》》運行INIT進程》》讀取/etc/inittab配置文件，》》執行/etc/rc.d/rc.sysinit腳本

| i 》》執行/etc/rc.d/rc腳本

執行/etc/c.d/rc.local |

啓動mingetty進程

進入grub ，cd /boot/grub 查看 ll

grub-install /dev/sda 導入

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

vim /etc/grub.conf 查看配置腳本

[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 所在硬盤

default=0 對應操作系統

timeout=5 等待時間過後5秒後自動選擇

splashp_w_picpath=(hd0,0)/grub/splash.xpm.gz grub的背景圖片

hiddenmenu 隱藏grub菜單

title Red Hat Enterprise Linux Server (2.6.18-164.el5) title爲標籤

ro ot (hd0,0) 引導分區根

kernel /vmlinuz-2.6.18-164.el5 ro root=LABEL=/ rhgb quiet 內核爲kernel

initrd /initrd-2.6.18-164.el5.img驅動程序

[root@localhost ~]# findfs LABEL=/ 查找標籤爲 / 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 解壓驅動包

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 進入初始化表

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 進入級別前所需執行的腳本（初始化腳本）

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 條件滿足可重啓

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備用電源

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

39 電源失效執行動作 –f快速啓動

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

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

42 來電了取消shutdown

44 # Run gettys in standard runlevels

45 1:2345:respawn:/sbin/mingetty tty1 （2345代表級別啓動sbin/mingetty tty終端）

46 2:2345:respawn:/sbin/mingetty tty2 （respawn動作註銷亦執行）

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進5級別所需執行的腳本

[root@localhost abc]# file /etc/rc.d/rc.sysinit 查詢其腳本類型

/etc/rc.d/rc.sysinit: Bourne-Again shell script text executable 可執行bash腳本

[root@localhost abc]# vim /etc/rc.d/rc.sysinit 查看腳本內容

#!/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 模擬grub損壞
[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
執行後發現正常啓動不了

執行Linux rescue 緊急救援模式
進入sysp_w_picpath下 cd /mnt/sysp_w_picpath
Chroot /mnt/sysp_w_picpath
Grub-install /dev/sda
Exit
Exit
系統將會重啓完畢
事例2
刪除boot/grub/下面的grub.conf
[root@localhost ~]# mv /boot/grub/grub.conf /boot/grub/grub.conf.old 改動grub.conf名=刪除
重新啓動後如下所示
進入grub下，執行如下命令，分別實現找硬盤，加載內核，加載驅動，然後 boot重啓，

重啓後記得要將/boot/grub下的grub.conf恢復或者手工編輯