Configure Replace -- trustworthy?

[Process153]

Hi all,

I did some testing with the above command on a 3750 I had spare and although it seems to work ok, I got a nasty surprise when I tried to demo it to a manager :O  Basically I'd created an archive, set some ports to default and wanted to show how the commands allowed me to restore the archived config but only amending the changed data.  No idea why, but the restore wiped the config off the switch and left me looking a bit stupid....  Well, stuff happens but.... I was wondering if this is something others have experienced???? Obviously I would not consider this for a production stack but it would be handy.  Appreciate your thoughts!

[Reza Sharifi]

Hi,

What are the commands you are using?

HTH

[Process153]

Hi Reza,

I'm just following this guide:

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/config-mgmt/configuration/xe-3s/config-mgmt-xe-3s-book/cm-config-rollback.html

Its working as expected now and of course, I make offline backups of the configs but its still a risk to consider using it in production. 

[Process153]

Just tried it again and its done the same thing.  Basically if you create a snapshot, leave it for a few hours or overnight as I did, take another snapshot and then make a change to the switch config, restoring the earliest config just seems to wipe it and return the switch to its out of the box config.  I'm assuming that the intended use for this was just to allow quick restoration of the original config and should never be considered a solid backup option for the switch.  Its a pity as it would be a very useful addition to the resiliency we have in place. 

[paul driver]

Hello

try and just replace a saved config from flash  without using the archive.

1) copy run flash:STAN.txt

2) make some changes

3) configure replace flash:STAN.txt

Does this work?

Then use the archive

Archive

path flash:STAN

time-period 240 ( 4 hrs)

rollback retry timeout 600

1) archive config - sh archive

#sh archive
The maximum archive configurations allowed is 5.
There are currently 1 archive configurations saved.
The next archive file will be named flash:STAN-<timestamp>-1
 Archive #  Name
   1        flash:STAN-Mar--1-05-51-44.797-0 <- Most Recent
   2        flash:STAN-Mar--1-05-53-37.280-1

2) make some changes

3) configure replace flash:STAN-Mar--1-05-51-44.797-0 revert trigger 1

ARCHIVE_DIFF-5-ROLLBK_CNFMD_CHG_START_ABSTIMER: User: console: Scheduled                            to rollback to config flash:STAN-Mar--1-05-57-31.599-1 in 1 minutes

ARCHIVE_DIFF-5-ROLLBK_CNFMD_CHG_WARNING_ABSTIMER: System will rollback to                            config flash:STAN-Mar--1-05-57-31.599-1 in one minute. Enter "configure confirm" if you wish to                            keep what you've configured

Note:If you don't confirm this rollback within 1 minute (Configure Confirm) it will auto rollback to the original confit prior to the replacing


tick tock.... tick tock...... (1 min)




- %ARCHIVE_DIFF-5-ROLLBK_CNFMD_CHG_ROLLBACK_START: Start rolling to: flash:STAN-Mar--1-05-57-31.599-1

res

paul

[Process153]

Thanks for taking the time Paul!  The process does work ok, its just that on two attempts using the oldest archive, the same process that normally works (the one we both describe above) has failed catastrophically.  My goal was to use the roll back feature as a "get out of jail card" in case of stupid.  I'll keep testing and report anything useful.

[paul driver]

Hello

I use the replace command quite often and have had no issues with it. I guess it depends on how you use it, As it can be used with/without rollback archive

res

Paul

[Joseph W. Doherty]

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Posting

Cannot recall what platforms I've tried it on, but I've found the command a bit "flakey", especially if there's much that was changed.

BTW, I've occasionally seen the IOS diff results be "flakey" too.  (Related?)

[Process153]

Yeah, I'm not convinced its consistent enough to trust.  Pity, its a good idea.