How to ensure that a user is a member of a group using Puppet

Question

Importantly, I want nothing more or less than this. I want to manage only a limited set of groups for a limited set of users, without ever changing any of their main groups or removing any other group memberships. Is this possible without resorting to a lot of execs? I'm running Puppet 6 without a master.

Answer 1

Looks like this is not possible in Puppet itself yet.