Workflow-Instance Model Interaction dpalma@vnomic.com

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 …

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)

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