SSM management: stop/remove SSM

[mpeuster]

When a service is terminated we might want to remove some of its SSMs as well (if they are not needed anymore).

To do so, the executive plugin base class should provide a method to remove SSMs from the system (e.g. delete its Docker image).

TODO: This might have more implications. What if a SSM wants to store persistent data? Might be a starting point for SSM repository discussion. But not urgent for now.

See: http://wiki.sonata-nfv.eu/index.php/Son-mano-base

[jbonnet]

@mpeuster so every SSM manages only one service?

[jbonnet]

@mpeuster ...instance: Rephrase: every SSM manages only one service instance? That might be too costly in real scenarios, no?

[mpeuster]

Good point. Yes we might allow SSMs for multiple services. I should re-formulate and say "we might want to remove a SSM".

[smendel]

The issue is outdated and does not reflect the current plan for the first year demo.