I've installed puppet modules as follows
% puppet module install puppetlabs-apache --environment production --target-dir /etc/puppet/environments/production/modules
How can I upgrade the puppetlabs-apache module?
puppet module upgrade tries to lookup the module within /etc/puppet directory
and puppet module upgrade doesnt have a target-dir flag to work with
I'll answer this myself for someone else who has the same confusion.
#) sudo puppet config print modulepath
/etc/puppet/environments/production/modules:/etc/puppet/modules:/usr/share/puppet/modules
puppet module upgrade command will search for module-to-be-upgraded in the above path.