Reload in.. how about terminal revert?

Ok.. so learnt something new today.. (every days a school day!)

Depending on your device and code, you should have the following command available to you…

config terminal revert time x

What this effectively does is save the running configuration to a backup file on the local flash and will revert to this config after x minutes…

If whatever work your carrying out is successful and you want to cancel the revert you simply confirm your changes are sound by entering;

config confirm

This only prevents your new working config from being overwritten, you will still need a write mem or copy run start to add the config to your startup configuration.

There are multiple advantages of doing this. Time being the primary one, no more waiting for the iOS to unpack etc.. but also this could be a multi purpose router, multi-vrf and you may have only impacted one vrf/service with a change – why affect the other X number vrf’s/services on the same router.

How

First of all we need to create the directory to store the configs, and then config archiving which is the process that will carry out the configuration backup;

Switch#mkdir flash:/configs
Create directory filename [configs]?
Created dir flash:/configs
Switch#
Switch(config)#archive
Switch(config-archive)#path flash:/configs
Switch(config-archive)#maximum 14
Switch(config-archive)#exit
Switch(config)#exit

Now, all we need to do prior to making a change, just like the reload in x command is set a timer;

Switch#configure revert timer 5
Rollback Confirmed Change: Backing up current running config to flash:configs-0

*May 20 20:15:02: %ARCHIVE_DIFF-5-ROLLBK_CNFMD_CHG_BACKUP: Backing up current running config to flash:configs-0

*May 20 20:15:02: %ARCHIVE_DIFF-5-ROLLBK_CNFMD_CHG_START_ABSTIMER: User: console: Scheduled to rollback to config flash:configs-0 in 5 minutes

It will remind you in a similar fashion to reload in..

*May 20 20:19:03: %ARCHIVE_DIFF-5-ROLLBK_CNFMD_CHG_WARNING_ABSTIMER: System will rollback to config flash:configs-0 in one minute. Enter “configure confirm” if you wish to keep what you’ve configured

If you ignore this, it will revert back to the prior configuration;

Rollback Confirmed Change: rolling to:flash:backups-0
Total number of passes: 1
Rollback Done
!
*May 20 20:20:03: %ARCHIVE_DIFF-5-ROLLBK_CNFMD_CHG_ROLLBACK_START: Start rolling to: flash:configs-0
*May 20 20:20:03: Rollback:Acquired Configuration lock.
*May 20 20:20:30: %PARSER-6-EXPOSEDLOCKRELEASED: Exclusive configuration lock released from terminal ’0' -Process= “Policy Manager”, ipl= 0, pid= 21

Or, if your happy with your modifications

Switch#configure confirm
*May 20 20:38:23: %ARCHIVE_DIFF-5-ROLLBK_CNFMD_CHG_CONFIRM: User: console: Confirm the configuration change

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