Automate backup with Cisco IOS’ kron

Let’s say you want to automatically back up your router’s running configuration (in RAM) to the startup configuration (in NVRAM) every Monday night at 10 P.M. You might want to make sure that the system is preserving router changes, even if the router losses power and even if someone forgets to save his or her changes.

The new IOS command scheduler makes this a relatively easy task. Here’s how you can use kron to accomplish this.

First, create a kron policy-list. Essentially, this policy list serves as your ‘script’, which lists what you want the router to run at a scheduled time. Here’s an example:

Router(config)#kron policy-list backup
Router(config-kron-policy)#cli write
Router(config-kron-policy)#exit

Next, create a kron occurrence, in which you tell the router when and how often you want to run this policy list (i.e., group of commands). Here’s an example:

Router(config)#kron occurrence backup at 22:00 Mon recurring
Router(config-kron-occurrence)#policy-list backup

This code sets up your backup job to run every Monday night at 10 P.M. (22:00 in military time).

Finally, verify that you’ve entered everything correctly by using the show command.

Router#show kron schedule

Kron Occurrence Schedule
backup inactive, will run again in 2 days 22:03:46 at 22:00 on Mon

Router#show running-configuration
(truncated)
kron occurrence backup at 22:00 Mon recurring policy-list backup
!
kron policy-list backup cli write
(truncated)

Notes:
You might be wondering why I used the write command instead of the copy running-configuration startup-configuration commands. While the copy run start command is interactive, the write command is not. In other words, write doesn’t prompt to verify what you want to do. It’s important to remember that the Cisco IOS Command Scheduler doesn’t allow any interactive commands.

You might be wondering if you could use kron to reboot the router. While it’s a good idea to use the command scheduler if you want to reboot your router on a regularly scheduled basis, you can perform a one-time delayed reboot using reload at with less complexity.

Additional uses for kron include clearing an interface on a daily schedule, clearing the internal log, and showing the routing table at set intervals and sending it to a log.

In some cases, you may want to log the failure or success of your commands. To do so, you can use the debug command. For example, to view all kron debugging, use debug kron all. (You can also use more specific kron debug commands.)

Once you’ve enabled debugging, send logging output to the router’s system buffer or to a syslog server. In that log, you’ll find the command output and whether the commands succeeded or failed.

Backup on FTP config example:
ip ftp source-interface loopback 0
ip ftp username ftp_username
ip ftp password ftp_password
file prompt quiet
!
kron policy-list backup
cli copy running-config ftp://10.20.30.40
!
kron occurrence daily-backup at 0:30 recurring
policy-list backup

~ by Safar Safarov on December 12, 2010.