[openstack-dev] [tripleo] When to use parameters vs parameter_defaults

Giulio Fidente gfidente at redhat.com
Fri Nov 10 09:20:32 UTC 2017

On 11/26/2015 03:17 PM, Jiří Stránský wrote:
> On 26.11.2015 14:12, Jiří Stránský wrote:


>> It seems TripleO is hitting similar composability and sanity limits with
>> the top-down approach, and the number of parameters which can only be
>> fed via parameter_defaults is increasing. (The disadvantage of
>> parameter_defaults is that, unlike hiera, we currently have no clear
>> namespacing rules, which means a higher chance of conflict. Perhaps the
>> unit tests suggested in another subthread would be a good start, maybe
>> we could even think about how to do proper namespacing.)
>> Does what i described seem somewhat accurate? Should we maybe buy into
>> the concept of "composable templates, externally fed
>> hierarchy-transcending parameters" for the long term?
> I now realized i might have used too generic or Puppetish terms in the
> explanation, perhaps drowning the gist of the message a bit :) What i'm
> suggesting is: let's consider going with parameter_defaults wherever we
> can, for the sake of composability, and figure out what is the best way
> to prevent parameter name collisions.
+1 I like very much the idea of parameter_defaults + strictier
namespacing rules

Specifically regarding namespaces, puppet was great but ansible doesn't
seem to be as good (at least to me), in fact I think we have chances for
conflicts in both THT and the ansible playbooks
Giulio Fidente

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