Best practice for releasing Perl modules to staging and live

[ian]

Hi
How best to ensure different environments have the same versions of Perl 
modules?

I have pondered this for a while having seen several clients get in a 
mess with different versions of Perl modules on different servers.

Some clients, will simply rsync files from one machine to another, 
including the Perl path directories. This is OK so long as the machines 
are the same OS and version. They still manage to get in a mess however 
since they still do a CPAN to all the machines at various times.

One client seemed to have it almost right, he put all required Perl 
modules into CVS and built them from a known version. This was a pain to 
work out the dependencies and the dependencies of dependencies etc. but 
at least you always knew where you were.

How about having a local CPAN repository? This still seems to have the 
problem of knowing which modules have been installed on each server.

Any other methods that should be considered?

Regards
Ian