1. Workflow-Instance Model Interaction

2. Workflow IM Information Requirements (basic)
Precondition
Determine if a workflow can be applied to a subset of nodes in a topology
Filter
Select the set of nodes on which the workflow will operate
Get lifecycle state
Know the state of a node to select the right sub-workflow/activities
Unknown state if node eventual enters a non-recoverable states
Set lifecycle state
Control state transitions as node operations are executed
Invoke operation
Pass parameters computed in the workflow
Deployment context access
Inputs
Instantiated policies
Service topology (Templates)
All respective meta info (Types)
Other?
Tenant
Location
Environment …

3. Workflow IM Query Requirements (advanced)
Qualify node by (node qualifier)
Type (Node Type Name)
Name (Node Template Name)
Ordinal (first, last, index, deterministic order for iterations/traversals)
Attribute values
node lifecycle state is an attribute
Defined or not (based on state)
Range (specific value is just a constrained range)
Any of (in)
Relation qualifier
Qualify by relation (relation qualifier)
Type
Name
Source nodes qualifier
Target nodes qualifier
Query syntax?
SQL like with graph semantics (in/out edges)

4. Pending issues Node lifecycle state Select template instances
Not defined in base types
getState (attribute)
setStat (state property?)
Select template instances
All instances created by a template
All templates create implicit homogenous sets of node instances
Groups in topology model can only refer to templates, i.e. they can’t target specific subsets of a sets
Where will IM queries be specified from
TOSCA workflow, policy
Can operations access instance model or just rely on inputs from TOSCA