On Fri, 2005-11-18 at 11:45 -0500, christian pearce wrote: > On 11/12/05, Viraj Alankar <[EMAIL PROTECTED]> wrote: > > 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? > > > Alva Couch gave a presentation about this: > > http://homepages.informatics.ed.ac.uk/group/lssconf/config2005e/Slides/cfengine.pdf
I have not seen this before. In fact it annoys me a little because it is factually incorrect and seems just to be an unnecessary slur on cfengine. I would not expect that from Alva. There is plenty to criticize in cfengine 2, but it does not help to misrepresent its behaviour. This network level divergence example is highly misleading. Of course there can be periods of divergence, but the talk seems to imply that some other tool could improve on the problem. In fact I would suggest that no other tool provides more consistency than cfengine today. Cfengine does not have a rollback function, because that would require it to remember everything about the previous states (which state is that?). It requirs exponentially growing memory and has no obvious versioning control. There is currently no fully predictable solution to this problem except to reprogram the state you want as if it were a forward change. M -- Mark Burgess Professor of Network and System Administration Oslo University College ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Work: +47 22453272 Email: [EMAIL PROTECTED] Fax : +47 22453205 WWW : http://www.iu.hio.no/~mark ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ _______________________________________________ Help-cfengine mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-cfengine
