Entities
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We clearly need orchestration entities like:
1. resources/roles/services/profiles

Also we need inventory entities:
2. nodes/networks/ifaces/cluster/release ?

Q: how to allow developer to extend this entities by modules?
Options:
1. Use completely schema-less data model
(i personally more comfortable with sql-like data models)
2. Dont allow anything except standart entities, if developer needs
to manage custom data - he can create its own micro-service and
then integrate it via custom type of resource
(one which perform query to third-part service)


Identities and namespaces
---------------------------
Identities required for several reasons:
- allow reusage of created once entities
- provide clear api to operate with entities
- specify dependencies with identities

Will be root namespace polluted with those entities?

Options:
1. We can create some variable namespace explicitly
2. Or use something like namepsace/entity (example contrail/network)


Multiple options for configuration
----------------------------------

If there will be same parameters defined within different
modules, how this should behave?

1. First option is concatenate several options and make a list of choices.
2. Raise a validation error that certain thing can be enabled with another.

Looks like both should be supported.


Deployment code
----------------

We need to be able to expose all functionality of any
particular deployment tool.

Current challenge: how to specify path to some deployment logic?