Recuperación de IOS desde un servidor TFTP

Recuperación de IOS desde un servidor TFTP

Escenario: se simula la peor condición, hay un crash de IOS, o un borrado accidental (aquí el borrado es explícito por

cuestiones de simulación) ó un borrado de mantenimiento (podría ser por actualización), seguido por ejemplo, de una

falla de energía eléctrica.

Este escenario se simuló tanto en Packet Tracer como con equipos reales.

Router_1841#ping 10.0.0.10 (aseguramos previamente la conectividad al TFTP)

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.0.0.10, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 31/31/32 ms

Router_1841#sh flash (verificamos archivo de IOS)

System flash directory:

File Length Name/status

4 33591768 c1841-advipservicesk9-mz.124-15.T1.bin (ver el número de archivo)

[33591768 bytes used, 30424616 available, 64016384 total]

63488K bytes of processor board System flash (Read/Write)

Router_1841#delete flash (borramos el sistema operativo)

Delete filename []? c1841-advipservicesk9-mz.124-15.T1.bin

Delete flash:/c1841-advipservicesk9-mz.124-15.T1.bin? [confirm] (enter)

Router_1841#reload (reiniciamos, podría ser una falla eléctrica o un crash)

Proceed with reload? [confirm] (enter)

%SYS-5-RELOAD: Reload requested by console. Reload Reason: Reload Command.

System Bootstrap, Version 12.3(8r)T8, RELEASE SOFTWARE (fc1)

Cisco 1841 (revision 5.0) with 114688K/16384K bytes of memory.

Boot process failed... (falla de arranque por falta de IOS)

The system is unable to boot automatically. The BOOT

environment variable needs to be set to a bootable

image.

rommon 1 > tftpdnld (necesitará configurarse variables de entorno)

usage: tftpdnld

Use this command for disaster recovery only to recover an image via TFTP.

Monitor variables are used to set up parameters for the transfer.

(Syntax: "VARIABLE_NAME=value" and use "set" to show current variables.)

"ctrl-c" or "break" stops the transfer before flash erase begins.

The following variables are REQUIRED to be set for tftpdnld:

IP_ADDRESS: The IP address for this unit

IP_SUBNET_MASK: The subnet mask for this unit

DEFAULT_GATEWAY: The default gateway for this unit

TFTP_SERVER: The IP address of the server to fetch from

TFTP_FILE: The filename to fetch

The following variables are OPTIONAL:

TFTP_VERBOSE: Print setting. 0=quiet, 1=progress(default), 2=verbose

TFTP_RETRY_COUNT: Retry count for ARP and TFTP (default=7)

TFTP_TIMEOUT: Overall timeout of operation in seconds (default=7200)

TFTP_CHECKSUM: Perform checksum test on image, 0=no, 1=yes (default=1)

FE_SPEED_MODE: 0=10/hdx, 1=10/fdx, 2=100/hdx, 3=100/fdx, 4=Auto(deflt)

rommon 2 > IP_ADDRESS=10.0.0.1 (variables mínimas para alcanzar el TFTP server)

rommon 3 > IP_SUBNET_MASK=255.255.255.0

rommon 4 > DEFAULT_GATEWAY=10.0.0.2 (aunque el TFTP sea local y no se utilice)

rommon 5 > TFTP_SERVER=10.0.0.10

rommon 6 > TFTP_FILE=c1841-advipservicesk9-mz.124-15.T1.bin (archivo de IOS)

rommon 7 > tftpdnld (ejecutamos, ahora con variables configuradas)

IP_ADDRESS: 10.0.0.1

IP_SUBNET_MASK: 255.255.255.0

DEFAULT_GATEWAY: 10.0.0.2

TFTP_SERVER: 10.0.0.10

TFTP_FILE: c1841-advipservicesk9-mz.124-15.T1.bin

Invoke this command for disaster recovery only.

WARNING: all existing data in all partitions on flash will be lost!

Do you wish to continue? y/n: [n]: y

Loading c1841-advipservicesk9-mz.124-15.T1.bin from 10.0.0.10 (carga desde el TFTP a RAM)

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

---resumido---

program flash location 0x61fd0000 (copia de RAM a FLASH)

program flash location 0x61fe0000

program flash location 0x61ff0000

program flash location 0x62000000

rommon 8 >reset (reinicio del equipo)

System Bootstrap, Version 12.3(8r)T8, RELEASE SOFTWARE (fc1)

Cisco 1841 (revision 5.0) with 114688K/16384K bytes of memory.

Self decompressing the image :

#######################################################################

################################################################# [OK] (arranque normal)

Restricted Rights Legend

---resumido---

%SYS-5-CONFIG_I: Configured from console by console

Router_1841> enable

Password:

Router_1841# sh flash

System flash directory:

File Length Name/status

5 33591768 c1841-advipservicesk9-mz.124-15.T1.bin (el número de archivo cambió de 4 a 5)

[33591768 bytes used, 30424616 available, 64016384 total]

63488K bytes of processor board System flash (Read/Write)

Router_1841#

Ejemplo de IOS crash en un router 831

*Mar 1 00:00:05.847: %LINK-3-UPDOWN: Interface Ethernet1, changed state to up (interfaz de Internet)

*Mar 1 00:00:15.719: %SYS-2-MALLOCFAIL: Memory allocation of 264 bytes failed from 0x800DA25C, alignment 4

Pool: I/O Free: 684 Cause: Memory fragmentation

Alternate Pool: None Free: 0 Cause: No Alternate pool

-Process= "Pool Manager", ipl= 0, pid= 6

-Traceback= 801396EC 8013A394 800DA260 801489E8 80148C04 80160A1C

*Mar 1 00:00:15.723: %SYS-2-NOBLOCK: printf with blocking disabled.

-Process= "Pool Manager", ipl= 0, pid= 6

-Traceback= 80082820 8013976C 8013A394 800DA260 801489E8 80148C04 80160A1C

Program (breakpoint) Exception (0x700)!

CPU Register Context:

VEC = 700 PC = 8015B8A0 MSR = 29032 CR = 30000005

LR = 8015B850 CTR = 80084920 XER = C000887F

R0 = 8015B850 R1 = 81062238 R2 = 80F00000 R3 = 80F65FB0

R4 = FFFFFFFE R5 = 0 R6 = 81062210 R7 = 80E10000

R8 = FF000000 R9 = 0 R10 = 9032 R11 = 80F65F48

R12 = A0000000 R13 = FFF32D6C R14 = 0 R15 = 0

R16 = 0 R17 = 0 R18 = 0 R19 = 0

R20 = 0 R21 = 0 R22 = 0 R23 = 80B144DC

R24 = 4 R25 = 800DA25C R26 = 800DA25C R27 = 108

R28 = 4 R29 = 80F7C670 R30 = 0 R31 = 0

Stack trace:

PC = 8015B8A0, SP = 81062238

Frame 00: SP = 81062238 RA = 80139774

Frame 01: SP = 81062248 RA = 8013A394

Frame 02: SP = 81062270 RA = 800DA260

Frame 03: SP = 810622A8 RA = 801489E8

Frame 04: SP = 810622C8 RA = 80148C04

Frame 05: SP = 810622E8 RA = 80160A1C

Frame 06: SP = 81062330 RA = 0

*** System received a Software forced crash *** (aquí nos notifica del system crash)

signal= 0x17, code= 0x700, context= 0x80f7ed98

PC = 0x8015b8a0, Vector = 0x700, SP = 0x81062238

System Bootstrap, Version 12.2(8r)YN, RELEASE SOFTWARE (fc1) (se reinicia del equipo, en este caso había que

TAC Support: http://www.cisco.com/tac desconectar la interfaz Internet ya que el DHCP

---resumido--- nuevamente,o poner IP fija o cambiar versión IOS)

En caso de tener varias imágenes IOS en flash para un troubleshooting rápido

Router_1841# sh flash (verificamos espacio disponible)

System flash directory:

File Length Name/status

5 33591768 c1841-advipservicesk9-mz.124-15.T1.bin

[33591768 bytes used, 30424616 available, 64016384 total] (30 megas para un IOS de 16 aprox.)

63488K bytes of processor board System flash (Read/Write)

Router_1841# copy tftp flash

Address or name of remote host []? 10.0.0.10

Source filename []? c1841-ipbasek9-mz.124-12.bin

Destination filename [c1841-ipbasek9-mz.124-12.bin]? (enter)

Accessing tftp://10.0.0.10/c1841-ipbasek9-mz.124-12.bin....

Loading c1841-ipbasek9-mz.124-12.bin from 10.0.0.10: !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!! [OK - 16599160 bytes]

16599160 bytes copied in 12.062 secs (307930 bytes/sec)

Router_1841# sh flash (verificamos)

System flash directory:

File Length Name/status

3 33591768 c1841-advipservicesk9-mz.124-15.T1.bin (IOS actual)

4 16599160 c1841-ipbasek9-mz.124-12.bin (nuevo IOS de contingencia)

2 28282 sigdef-category.xml

1 227537 sigdef-default.xml

[50446747 bytes used, 13569637 available, 64016384 total]

63488K bytes of processor board System flash (Read/Write)

Router_1841#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Router_1841 (config)# boot system flash c1841-ipbasek9-mz.124-12.bin (elejimos imagen a utilizar)

Router_1841 (config)# ^Z

Router_1841#

%SYS-5-CONFIG_I: Configured from console by console

Router# copy ru st (guardamos cambios, este comando es parte de la running-config)

Building configuration...

[OK]

Router_1841# reload (reiniciamos)

Proceed with reload? [confirm] (enter)

%SYS-5-RELOAD: Reload requested by console. Reload Reason: Reload Command.

System Bootstrap, Version 12.3(8r)T8, RELEASE SOFTWARE (fc1)

Cisco 1841 (revision 5.0) with 114688K/16384K bytes of memory.

Self decompressing the image :

########################################################################## [OK]

Restricted Rights Legend

---resumido---

Cisco IOS Software, 1841 Software (C1841-IPBASEK9-M), Version 12.4(12), RELEASE SOFTWARE (fc1)

Technical Support: http://www.cisco.com/techsupport

Compiled Mon 15-May-06 14:54 by pt_team

Image text-base: 0x600790EC, data-base: 0x61480000

---resumido---

Cisco 1841 (revision 5.0) with 114688K/16384K bytes of memory.

Processor board ID FTX0947Z18E

M860 processor: part number 0, mask 49

2 FastEthernet/IEEE 802.3 interface(s)

191K bytes of NVRAM.

63488K bytes of ATA CompactFlash (Read/Write)

Press RETURN to get started!

%LINK-5-CHANGED: Interface Vlan1, changed state to up

%LINK-5-CHANGED: Interface FastEthernet0/0, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up

%LINK-5-CHANGED: Interface FastEthernet0/1, changed state to up

%LINK-5-CHANGED: Interface Vlan1, changed state to up

%SYS-5-CONFIG_I: Configured from console by console

Router_1841# sh runn (verificación)

Building configuration...

Current configuration : 510 bytes

version 12.4

no service timestamps log datetime msec

no service timestamps debug datetime msec

no service password-encryption

hostname Router

boot system flash c1841-ipbasek9-mz.124-12.bin

---resumido---

end

Router_1841#

(2012) Boring pretty girls with networking.

Rosario, Argentina