(I apologize for getting to this so late.)

2014-01-27 19:33 GMT+01:00 Kevin Fenzi <kevin@scrye.com>:
* The roles use cockpit to manage and configure the server role post

Cockpit should be a mechanism, but not the only mechanism: fully-automated, kickstart-driven installs need to be possible.  One thing that would work is an executable (fedora-role-deploy?) that accepts a possibly empty kickstart-like service-specific "deployment configuration"; kickstart can invoke this directly, perhaps with a here-doc, and cockpit can generate the configuration from a GUI and call that executable.  To get even more fancy, fedora-role-deploy could interactively ask if something is missing in the deployment configuration, but that's perhaps inviting too much complexity.

* We create a new fedora-server-$role package for each role. This role
  package contains the 'glue' we add to turn this into a fedora server
  role from just a install with the packages and local config. We will
  need to come up with guidelines and what these packages will contain,

  7. We may have a fedora-server-base or fedora-server-common package
  to contain common/base stuff all roles need/user and make the role
  packages require it. We would need to be very careful about updates
  of this however.

Ability to cleanly upgrade is a significant concern here.  I think the worst case is a major update to something like a database, involving a format change, where you need to keep the old version running to do a data dump, and have the new version installed at the same time to receive the data dump.  That would require:
Another desirable feature would be to have a non-destructive upgrade opportunity: install a newer version of the role package, ask it to do an upgrade, and have the role package refuse an upgrade because it would lead to data loss (or require non-trivial downtime or administrator's manual involvement).

So, I'm leaning towards a design where fedora-server-$role is not a package for a specific version of a role, but for all past versions.  Therefore:
What do you think?