On Wednesday, May 22, 2013 1:48:26 AM UTC-5, David Schmitt wrote: > > > Just because it is not well known. ensure_packages seems to be designed > for exactly the use-case you are describing: you have two modules both > requiring the same utility packages without caring at all about versions > or > anything else. > > To elaborate: contrary to (most, all?) other resources, packages have this > no-parameter use case, which allows conflict-free merging. Managing more > complex resources (users, files) would require more cooperation between > modules to ensure that the different requirements do not step on each > other. > > No, the only resource types that could have no-parameter use cases would be those with no parameters, but there are none such. Some types, including Package, admit sensible use cases involving only default parameter values, but that's a rather different thing, and not necessarily the thing you want. Also, either ensure_packages() must ignore the context-specific Package parameter defaults (in which case those won't work, which could be a hard-to-debug surprise) or else uses of the function in different contexts can be inequivalent, so that one set of package parameters is chosen over all others, at semi-random (also a potential nasty surprise).
Furthermore, ensure_packages() is inherently parse-order dependent, and parse-order dependencies are a major source of concern in Puppet manifest design. That is mitigated in this case if you require that packages used with ensure_packages() are never declared any other way, but then you're placing a constraint on your manifest set that is easy to overlook, that might not be enforced by the catalog compiler, and that you cannot by any means expect third-party modules to comply with. Ensure_packages() is bad juju. If you design your manifest set well in the first place then you will not need it. Sadly, the current state of module compatibility is that in some cases you may need to refactor third-party modules to achieve the overall design criteria you want. At least Puppet will notify you of those cases (provided that ensure_packages() or some similar device doesn't mask it). John -- You received this message because you are subscribed to the Google Groups "Puppet Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to puppet-users+unsubscr...@googlegroups.com. To post to this group, send email to puppet-users@googlegroups.com. Visit this group at http://groups.google.com/group/puppet-users?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
