Multiple Service Managers

[AhmadAlamoush]

Do we want to have/need multiple service managers per device or is one service manager per (container) per device sufficient? In case that we opt for multiple service managers, which and how to select the service manager that should manage app.

• [x] Basic implementation allowing for multiple service managers
• [x] Service AAS client selecting service manager
• [x] Open (from #100): How to handle a multi-instance, multi-container start/stop.
• [ ] Testing with PETE

[eichelbe]

Actual plan: (@dzikaswinia @JimmyAppel)

• We keep for now the legacy service manager elements in the device AAS and add a new collection serviceManagers. The serviceManagers contains in individual elements the service managers on the actual device, the top-level service manager is just the first one as it is now. It is also added using its JVM id into serviceManagers.
• Activated only via deployment plans and appId there (shall be the same as in the configuration model)
• ServiceManager declares the appIds it is responsible for, it has been built for, it has the dependencies for. Can be done in iipecosphere.yml of service manager or for containers more convenient in environment variable ENV_SUPPORTED_APPIDS or in JVM property iip.supportedAppIds. See also platform handbook 0.6.0-SNAPSHOT (intern).
• Platform AAS/CLI passes appId to ServiceManager AAS client. This selects the appropriate service manager, either the only one available as it is now or from those supporting the appId the one with the lowest number of running service instances (very primitive, initial load distribution).

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