convergence and undoing changes

[Viraj Alankar]

I'm a little confused on how to deal with undoing changes in a
convergence methodology. Let's say I decide to push a file
/usr/local/bin/foo to all of my servers. Then I decide not to do this,
and take it out of cfengine. This will be correct for new servers
'converging,' but not the current ones which still have the file. Is
the normal procedure to have cfengine remove the file if it is there?
But then that removal is unnecessary on new servers.

Or is a better method to make cfengine undo the changes temporarily,
and remove this 'undo' configuration once all of the old systems are
fixed?

This is a simple file copy example, but can be extended to other
complicated tasks (editfiles, etc). I'm wondering how others approach
this problem. I just envision getting into a situation where there is
a ton of 'undo' code that becomes unwieldy. I understand it would be
best to avoid needing to undo anything, but that may not always be
practical.

Thanks,

Viraj.