Lessons · Network switches · being able to go back
The old switch is the rollback
A configured switch on a bench is a five-minute recovery; an erased one is a rebuild. It goes when the replacement has held for a week.
Hone is a place to practise programming. This is one of its lessons, written out in full and free to read without an account.
What it is for
The fastest way back from a swap that went wrong is the box that was working an hour ago. Wiping it on the night, or sending it back the same day, throws that away for no gain.
How to think about it
Leave it configured and saved, so it boots as itself if it goes back in. Then wipe it properly -- both files -- once the new one has proved itself.
Worked example
enableIn, on the box that is going out.
configure terminalOne last thing before it comes out of the rack.
hostname IDF3-OLDRenamed, so nobody confuses the two if both end up powered on.
endOut.
write memorySaved, so it boots as itself if it has to go back in.
Your turn
Make the old switch boot as itself if it goes back in the rack.
write
Console into a switch
The trap
Erasing it on the night. It is the only rollback you have until the replacement has run for a while.