The current ACM state machine works but it is incosistent in the way it handles error states or failed transitions. A composition and its elements can get "stuck" in transition states.
We need to
- Specify what the current state machine is for both compositions and elements and describe what the state machine for both should be
- Specify what the behaviour of the runtime and participants should be in each state
- Specify what the behaviour should be for the runtime and participants should be in transitions
Specifically we need to clarify:
- State of the composition elements
- State of the overall composition is derived from the composition element states
- Admin state/Running state
- When all the elements are fully up and configured, the go to state Passive, when all elements are in Passive, the full composition goes to Passive
- Error states: Are they parallel sates or part of the same state?
- There should “it didn’t work” states like “Passive-Error” or “Run_Error” (names to be decided later)
- Describe what the “Running” state means and what the participant should do in Passive->Running and Running->Passive transitions.
- Say a K8S service crashes, how do we feed that back? Running_Error. The state of the POD is only checked during startup. It is not periodically checked. There should be supervision.
ACM Element States in Participants
This section describes the state handling in ACM Elements in Participants
The following states are the only states in participants:
Then, a Control Loop Element can be running a number of operations, each of which has an operational state:
...
To
State
...
UNINITIALIZED
UNINITIALIZED
...
PASSIVE
UNINITIALIZED_ERROR
...
PASSIVE
PASSIVE
...
UNINITIALIZED
PASSIVE_ERROR
...
UNINITIALIZED_ERROR
UNINITIALIZED_ERROR
...
UNINITIALIZED
UNINITIALIZED_ERROR
...
A Control Loop Element has a status indicator
...
Each participant also records a log of all operations that occur, recording the information below:
...
To
State
...
Automation Composition Management manages a number of states of various types to manage the lifecycle of compositions. Those states are described here. Please also see the ACM System Level Dialogues page to see the system dialogues that change states and how states interrelate in detail. Please also see ITU Recommendation X.731, which is reflected in the states of AC Element Instances.
Participant State
ACParticipant states are NOT managed by ACM but the state of a participant is recorded and supervised by ACM.
Automation Composition Type State
The states that an Automation Composition Type can have are shown in the diagram below.
Automation Composition Element Type State
The states that an Automation Composition Element Type can have on ACM Runtime are shown in the diagram below.
The states that an Automation Composition Element Type can have on a Participant are shown in the diagram below.
Automation Composition Instance State
The states that an Automation Composition Instance can have are shown in the diagram below.
Automation Composition Element Instance State
The states that an Automation Composition Element Instance can have on ACM Runtime are shown in the diagram below.
The states that an Automation Composition Element Instance can have on a Participant are shown in the diagram below.