Juniper EX交换机系统恢复

1 交换机无法正常启动的解决办法

EX交换机在突然掉电或非正常关机的情况下，设备重新启动后，可能会出现一直卡着启动进程或OS引导失败的场景，本文列出几种常见的模式及解决方法（注：本文档中提到的操作可能出现设备原有配置丢失情况出现，另外，对于通过命令关机时，强烈建议等到所有进程都halt时再对进行掉电操作）。

通常，交换机无法正常启动时，通过console输出为：

1.系统直接进入Loader模式，Loader Prompt ( loader >) ； 2.系统进入Debug模式，Debug Prompt (db>) ； 3.系统进入UBoot模式，UBoot Prompt (=>)； 4.系统能正常启动，但各系统进程无法正常加载； 5.系统提示Can't load kernel error ；

2 系统直接进入Loader模式解决办法

方法一 TFTP方式恢复交换机

1.准备好TFTP服务器，然后把Junos安装文件上传至TFTP的root目录层次下； 2.用console连接交换机，并对设备进行加电；

# When you see the \

Then press [Enter] to boot immediately, or space bar for command prompt.

Hit the space bar to enter the manual loader. The loader > prompt displays.

(NOTE: There is a 1 second delay for hitting the space (TIPS: you can hit space bar after you see \

bar)

3.配置交换机的管理ip地址；

loader>

set

ipaddr=192.168.100.2

loader> set loader> set serverip=192.168.100.1

netmask=255.255.255.0

4.从TFTP安装Junos;

loader> install tftp://192.168.100.1/jinstall-ex-9.1R2.7-domestic-signed.tgz

==============================================

This part of the boot log is related to the steps listed above ==============================================

Consoles: U-Boot console Found compatible API, ver. 7

FreeBSD/PowerPC U-Boot bootstrap loader, Revision 2.1 (marcelm@apg-bbuild01.juniper.net, Wed Feb 6 11:23:55 PST 2008) Memory: 1024MB Loading /boot/defaults/loader.conf /kernel data=0x9dc348+0x6df44 syms=[0x4+0x87bb0+0x4+0x8e152]

Hit [Enter] to boot immediately, or space bar for command prompt. <-------HIT SPACE BAR-------

Type '?' for a list of commands, 'help' for more detailed help. loader> loader> set ipaddr=192.168.100.2 loader> set netmask=255.255.255.0 loader> set serverip=192.168.100.1 loader> install tftp://192.168.100.1/jinstall-ex-9.1R2.7-domestic-signed.tgz Speed: 100, full duplex Package /jinstall-ex-9.1R2.7-domestic-signed.tgz is signed... /kernel data=0x504104+0x32e60 syms=[0x4+0x50a00+0x4+0x6366f] Kernel entry at 0xa0000100 ... GDB: no debug ports present KDB: debugger backends: ddb KDB: current backend: ddb Copyright (c) 1996-2008, Juniper Networks, Inc. All rights reserved. Copyright (c) 1992-2006 The FreeBSD Project. ... snip ...

==============================================

或参考KB11752 - Installing EX-Series software from a TFTP server from Loader prompt OR Recovering from a Failed Software Upgrade on an EX Series Switch.

方法二、USB方式恢复交换机

步骤一、将需要安装的Junos软件copy至U盘根目录下； 步骤二、用console连接交换机，并对设备进行加电；

# When you see the \

Then press [Enter] to boot immediately, or space bar for command prompt.

Hit the space bar to enter the manual loader. The loader > prompt displays.

(NOTE: There is a 1 second delay for hitting the space (TIPS: you can hit space bar after you see \

bar)

步骤三、输入install file:///jinstall-ex-3200-10.0S1.1-domestic-signed.tgz

注：交换机将从U盘进行安装；

或参考KB10386 - Boot from USB and Recovering from a Failed Software Upgrade on an EX-series Switch

OR Booting an EX Series Switch Using a Software Package Stored on a USB Flash Drive

3 系统进入Debug模式解决办法

步骤一，在db>模式下输入以下命令收集相关信息： db> db> db> db> db> db> db>

db> show uma

x/s

version

alltrace

ps allvms msgbuf registers

lock

show show show show

步骤二，完成以上步骤后，输入cont db> cont

Do you get the CLI prompt? No - Continue with 步骤三. Yes - Jump to 步骤四.

步骤三,重启交换机，从loader模式进行恢复；如果交换机无法进入loader模式，请开case进行处理或采用install format方式解决；

步骤四，在cli下用show system core-dumps看是否存在core-dump文件，如果有的话，可先进入shell模式层下，然后进入/var/core-dumps directory目录下，将文件上传至FTP服务器；

或参考KB20635 - While booting up, switch stuck in db> mode

4 系统进入UBoot模式解决办法

按照以下三个步骤进行操作：

1. 在UBoot模式输入reset重启交换机； 2. Break启动顺序进入loader>模式

# When you see the \

Then press [Enter] to boot immediately, or space bar for command prompt.

Hit the space bar to enter the manual loader. The loader > prompt displays.

(NOTE: There is a 1 second delay for hitting the space (TIPS: you can hit space bar after you see \3. 然后按照方法一中的Loader模式进行处理；

bar)

5 系统能正常启动，但其它各系统进程无法加载的解决方法

设备启动后存在以下报错

root@GZ-EX4200-1> show chassis alarms no-forwarding

error: the alarm-control subsystem is not running

root@GZ-EX4200-1> show chassis hardware detail no-forwarding error: the chassis-control subsystem is not running

1. 对于10.4R3以前的版本，可按照Loader模式的方法进行处理；

2. 对于10.4R3之后的版本，存在双分区双系统，而Junos loader默认是用disk99,

如果这个分区的系统坏了之后，会一直卡着Loader>模式；

步骤一，设备加电后，输入以下命令；

=> setenv loaddev disk99: => saveenv

=> reset

步骤二，在JunOS loader模式下选择从internal NAND flash 启动Junos loader> set currdev=disk0: loader> boot

步骤三，在shell模式删除以下文件； (Login as root)

# ls -al /boot/loader.conf.local # rm /boot/loader.conf.local

步骤四，Revert the change made in step one: # nvram unsetenv loaddev 步骤五，Reboot

6 Can't load kernel error解决办法

如果设备重启后，一直显示以下错误: can't load '/kernel' can't load '/kernel.old' 可参照DB模式进行恢复；

7 Junos在备用分区启动（KB23180）

开机提示：

Warning:**************************************************************************************** ** **

** WARNING: THIS DEVICE HAS BOOTED FROM THE BACKUP JUNOS IMAGE ** ** **

** It is possible that the primary copy of JUNOS failed to boot up ** ** properly, and so this device has booted from the backup copy. ** ** **

** Please re-install JUNOS to recover the primary copy in case ** ** it has been corrupted. ** ** **

***************************************************************************************

设备告警信息：

user@switch> show chassis alarms