Automate Cisco configuration backup

Introduction

In this article we are going to create expect script that backup the configuration of Cisco devices in your network every midnight 😉

For this setup we need Linux machine (Ubuntu is my favorite), tftp-server, expect shell and some bash here and there

Ok lets do this !

tftp-Server:

I assume you already have your linux machine up and running (like I said I prefer Ubuntu)

First install tftp-server

sudo apt-get install tftpd-hpa

Then, edit the tftpd-hpa configuration file.

sudo vim /etc/default/tftpd-hpa

and change the line ..

TFTP_OPTIONS=”–secure”

to

TFTP_OPTIONS=”-s -c”

change the permission of /var/lib/tftpboot

sudo chown -R tftp /var/lib/tftpboot

Finally restart the service

sudo service tftpd-hpa restart

I didn’t  expect that !

Ok, first of all install expect shell

sudo apt-get install expect

Next, expect script we are goning to make “expects” from you IP addresses and passwords to work. so you have to create a file (devices.txt) contain your devices

10.10.10.1

10.10.10.2

10.10.10.3

core-sw01

core-sw02

Next, create a shell script (config-sw.sh) that execute our expect script (tricky huh !)

#!/bin/bash

# Feed the expect script a device list & the collected passwords
for device in `cat devices.txt`; do
./exp-config-sw.exp $device ;
done

and last but not least the “expect” script, here is the whole file and we will go through it segment by segment

#!/usr/bin/expect -f
#################### First Segment ########################
set hostname [lindex $argv 0]
set username “admin”
set password “password”
# Log results
log_file -a ~/results.log
#################### Second Segment ########################
# Announce which device we are working on and at what time
send_user “\n”
send_user “>>>>> Working on $hostname @ [exec dateo] <<<<<\n”
send_user “\n”
spawn telnet $hostname
expect {
timeout { send_user “\nTimeout Exceeded – Check Host\n”; exit 1 }
eof { send_user “\nTelnet Connection To $hostname Failed\n”; exit 1 }
“*ser*” {
send “$username\n”
expect “*assword:” {
send “$password\n”
expect “*#”
}
}
}
#################### Third Segment ########################
send “copy running-config tftp://10.10.10.254/$hostname-[exec dateo].txt \n”
expect “Source”
send “\n”
expect “Address”
send “\n”
expect “Destination”
send “\n”
expect “#”
send “exit\n”
expect “:~\$”

exit

The #First Segment# set the IP address, username and password

the IP address ($hostname ) is received from the bash shell script. a log file is created to log what’s going on

The #Second Segment# show the user what the script is doing by printing every command and the output of that command

• spawn telnet $hostname #establish a telnet session to $hostname
• if timeout occurred notify user
• expect user name and password pattern and send each promptly

The #Third Segment# copy the configuration to a tftp-server the destination file name is the $hostname-dateo

dateo is a modified version of date with spaces substituted with ‘-‘. all you have to do is create a file dateo.sh and copy it to /usr/ bin/

#!/bin/bash
date | sed ‘s/ /-/g’

Finally cron it

#sudo crontab -e

0 0 * * *       /bin/config-sw.sh

References

https://help.ubuntu.com/community/TFTP

Expect Scripting For Network Engineers (Cisco)

http://stackoverflow.com/questions/3984134/how-to-write-a-cron-that-will-run-a-script-every-day-at-midnight