Improve Workload Management API to support improved app management (Upgrade/Rollback)

[ajcraig]

Feature description

Goal: This feature aims to improve the application management API functionality to support upgrades / reconfiguration / and enable rollbacks.

Provide adequate technical acceptance criteria(s) associated with this feature below:

SUP proposal should address the following functionality gaps and propose a solution to enable support:

• How to deal with a new version of application being upgraded in place
• How to with an updated configuration to an app already running(reconfiguration)
• Ensure rollbacks can be supported with this strateg
• Ensure Workload deployment status mechanism is updated to support the new functionality proposed for items above.

MUST ensure if impacting the application description package, the information is described to ensure full impact is transparent.

Although not required, it is highly encouraged to provide feature use-cases below:

Improved control for WFMs to manage applications on margo edge devices. Enables full app lifecycle management while following the approved strategies already in the specification.

Additional information

No response

[phil-abb]

We need to be careful with anything dealing with rollbacks. We cannot assume it's OK to roll back an application. Also, depending on how this is handled, it could mean we are starting to get into the realm of telling application developers how to implement their applications.

[phil-abb]

Upgrades are also an area we need to think about from the perspective of an application supplier. We cannot assume it's ok to upgrade from one version to just any newer version. Right now, there is nothing in Margo that allows an application supplier to describe what versions are safe to upgrade from to the new version. For example, I have a 1.0 version of my application and a 2.0 version. To upgrade to version 2.0, the app must first be upgraded to at least version 1.5. This would mean, as an application supplier, I would want some way of saying version 2.0 requires >= version 1.5 to be installed if doing an upgrade.