Re: [lmap] /capabilities/task* vs /capabilities/tasks/task*

[Juergen Schoenwaelder <[e-mail]>]

On Tue, Jan 03, 2017 at 08:27:37PM +0000, Carey, Timothy (Nokia - US) wrote:
> Juergen,
> The task capabilities just point to the registry objects (registry and roles) - they don't have programs assigned.
>

In the information model; the data model also allows to have entries
without a registry object which identifies a program to run (and this
is what I have implemented).

The question, however, is what exactly happens if a configured task
refers to a capability task that does not exist. There are different
options:

a) The configuration is invalid. This is problematic in a YANG context
   since the idea is that validity of a configuration should not
   depend on the specific runtime capabilities of a system.

b) The configuration may be valid but of configured tasks that refer
   to tasks that are not among the capabilities are not executed.

>From a YANG perspective, semantics b) seem to make most sense. But
then the question is how this plays with actions (that refer to
configured tasks) and schedules (that refer to actions). There are
again differnet options:

b1) An action that refers to a configured task that references a
    non-existing capability is simply not executed.

b2) Any schedule that includes an action that that refers to a
    configured task that references a non-existing capability is not
    executed.

Recall that we have differnet execution modes. For pipelines
schedules, b2) might make sense, for parallel or sequential schedules
b1) might make sense.

>From the discussion around intended and applied configs, it seems b2
seems to make most sense because b2) essentially says that any actions
and their schedules that reference non-existing capabilities are not
part of the applied config, that is, the applied config becomes a
proper subset of the schedules (and not a subset of the actions of the
schedules).

/js

-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
Fax:   [phone]         <http://www.jacobs-university.de/>