IOS, IOS XE and configure … revert timer X

If you are familiar with IOS XR and JunOS, it lacks a rollback to IOS and IOS XE. You can do it with “archive” such as :

1. Configure where your archive will be stored.
2. Say to your OS to “archive” at a point
3. Configure your router with a “revert timer”
4. Confirm if it is ok for you

Here we go in details now :

1. Configure where your archive will be stored.

Router# conf t
Router(conf)# archive
Router(conf-archive)# path bootflash:myconfig
Router(conf-archive)# maximum 10
Router(conf-archive)# end
Router# wr

2. Say to your OS to “archive” at a point

Router# archive config 
Router# 
Router# show archive
The maximum archive configurations allowed is 10.
There are currently 1 archive configurations saved.
The next archive file will be named bootflash:myconfig-<timestamp>-1
 Archive #  Name
   1        bootflash:myconfig-Jan--3-2022-08-34-34.348-CET-0 <- Most Recent
   2         
   3         
   4         
   5         
   6         
   7         
   8         
   9         
   10   
Router#     

3. Configure your router with a “revert timer”

Router# configure terminal revert timer 1
Router(conf)# Rollback Confirmed Change: Backing up current running config to bootflash:myconfig-Jan--3-2022-08-35-01.511-CET-1

Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#Rollback Confirmed Change: Rollback will begin in one minute.
Enter "configure confirm" if you wish to keep what you've configured

*Jan  3 2022 08:35:01.670 CET: %ARCHIVE_DIFF-5-ROLLBK_CNFMD_CHG_BACKUP: Backing up current running config to bootflash:myconfig-Jan--3-2022-08-35-01.511-CET-1
*Jan  3 2022 08:35:01.670 CET: %ARCHIVE_DIFF-5-ROLLBK_CNFMD_CHG_START_ABSTIMER: User: console(Priv: 15, View: 0): Scheduled to rollback to config bootflash:myconfig-Jan--3-2022-08-35-01.511-CET-1 in 1 minutes
*Jan  3 2022 08:35:01.670 CET: %ARCHIVE_DIFF-5-ROLLBK_CNFMD_CHG_WARNING_ABSTIMER: System will rollback to config bootflash:myconfig-Jan--3-2022-08-35-01.511-CET-1 in one minute. Enter "configure confirm" if you wish to keep what you've configured
Router(conf)# hostname BLAH
BLAH(conf)#
[................... WAITING FOR A MINUTE ........................]
Rollback Confirmed Change: rolling to:bootflash:myconfig-Jan--3-2022-08-35-01.511-CET-1

!Pass 1
!List of Rollback Commands:
no hostname BLAH
hostname Router
end


Total number of passes: 1
Rollback Done

*Jan  3 2022 08:36:01.669 CET: %ARCHIVE_DIFF-5-ROLLBK_CNFMD_CHG_ROLLBACK_START: Start rolling to: bootflash:myconfig-Jan--3-2022-08-35-01.511-CET-1
*Jan  3 07:36:01.722: Rollback:Acquired Configuration lock.


Router(conf) # end

4. Confirm if it is ok for you

If between your “conf t revert time X” and t0+X, you are ok with the configuration you have made, so you can confirm your changes.

Router# configure confirm

That’s it ! Have fun.