Linux配置网络rescue mode

Linux遇到严重的系统故障时，就需要用Linux的rescue mode进入系统进行修复，假如要修复对象的机器没光驱呢，就不能从光盘进入rescue了，而且随身带着光盘也麻烦，试想一下在笔记本上配一个各个系统版本的rescue，到时候只要网线一连，就能进入rescue进行修复了。

在网络上有很多关于kickstart+dhcp+dns+vsftp++tftp+pxe的网络自动安装文档，其实网络rescue原理也一样。

一：dhcp配置

安装dhcp（略）

1. [root@server2 ~]# vim /etc/dhcpd.conf
2. ddns-update-style none;
3. subnet 192.168.238.0 netmask 255.255.255.0 {
4. option routers 192.168.238.1;
5. option subnet-mask 255.255.255.0;
6. option domain-name "example.com";
7. default-lease-time 21600;
8. max-lease-time 43200;
9. pool {
10. range 192.168.238.2 192.168.238.99;
11. }
12. next-server server2.lanv.com;
13. }
14. option space PXE;
15. class "PXE" {
16. match if substring(option vendor-class-identifier, 0, 9) = "PXEClient";
17. option vendor-encapsulated-options 01:04:00:00:00:00:ff;
18. option boot-size 0x1;
19. filename "pxelinux.0";
20. option tftp-server-name "server2.lanv.com";
21. option vendor-class-identifier "PXEClient";
22. vendor-option-space PXE;
23. }
24. [root@server2 ~]# service dhcpd restart
25. Shutting down dhcpd: [ OK ]
26. Starting dhcpd: [ OK ]

二：配置vsftp
安装略

1. [root@server2 ~]# cd /var/ftp/pub/
2. [root@server2 pub]# mkdir RHEL5.7

把rhel5.7光盘内容都cp到/var/ftp/pub/RHEL5.7里

1. [root@server2 pub]# service vsftpd start
2. Starting vsftpd for vsftpd: [ OK ]
3. [root@server2 pub]# chkconfig vsftpd on

1. [root@server2 Oracle]# vim /etc/xinetd.d/tftp
2. service tftp
3. {
4. socket_type = dgram
5. protocol = udp
6. wait = yes
7. user = root
8. server = /usr/sbin/in.tftpd
9. server_args = -s /tftpboot
10. disable = no
11. per_source = 11
12. cps = 100 2
13. flags = IPv4
14. }
15. [root@server2 oracle]# service xinetd restart
    Stopping xinetd:                                           [  OK  ]
    Starting xinetd:                                           [  OK  ]

1. [root@server2 isolinux]# df -h /mnt
2. Filesystem Size Used Avail Use% Mounted on
3. /dev/hdc 3.6G 3.6G 0 100% /mnt
4. [root@server2 mnt]# cd isolinux/
5. [root@server2 isolinux]# ls
6. boot.cat general.msg isolinux.bin memtest param.msg splash.lss vmlinuz
7. boot.msg initrd.img isolinux.cfg options.msg rescue.msg TRANS.TBL
8. [root@server2 isolinux]# cp boot.msg /tftpboot/
9. [root@server2 isolinux]# cp initrd.img /tftpboot/initrd-5.7.img
10. [root@server2 isolinux]# cp -r isolinux.cfg /tftpboot/default
11. [root@server2 isolinux]# cp vmlinuz /tftpboot/vmlinuz-5.7
12. [root@server2 isolinux]# cp /usr/lib/syslinux/pxelinux.0 /tftpboot/
13. [root@server2 isolinux]# cd /tftpboot/
    [root@server2 tftpboot]# mkdir pxelinux.cfg
    [root@server2 tftpboot]# mv default pxelinux.cfg/
14. [root@server2 tftpboot]# ls
    boot.msg  initrd-5.7.img  pxelinux.0  pxelinux.cfg  vmlinuz-5.7