[OASIS Issue Tracker] (TOSCA-172) 2014 March - Public Comment Questions (Plans, Instance Counts, and linking SW Nodes)

[OASIS Issues Tracker <workgroup_mailer@lists.oasis-open.org>]

    [ https://tools.oasis-open.org/issues/browse/TOSCA-172?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=37008#comment-37008 ] 

Frank Leymann  commented on TOSCA-172:
--------------------------------------

My two cents on your questions wrt Plans in TOSCA:

Ad question (1): We distinguish between "declarative" processing of a topology template and "imperative" processing of a topology template. If no plan is defined, the topology template has to be processed declaratively, i.e. the behavior you sketch under (1.a) is meant. If your engine always expects plans, you have an imperative engine and you will reject the processing of the service template. 

Ad question (2): The focus of TOSCA 1.0 was on the declarative style of processing service templates. The work on the Simple Profile aims at restricting to scenarios often seen in todays cloud deployments - which is declarative. Thus, plans won't be in the first version of the Simple Profile; please note that this is my personal opinion, the TC may decide differently.

Ad question (3): In order to be able to execute plans in an interoperable manner, a "Plan Portability API" is needed. A first draft of this API has been submitted to the TC (https://www.oasis-open.org/apps/org/workgroup/tosca/download.php?document_id=46381); an overview on this API can be found here: https://www.oasis-open.org/apps/org/workgroup/tosca/download.php?document_id=49559  Because the TC decided to focus on the declarative style first, this API has not been kept up to the latest features of TOSCA 1.0.  We are considering to submit a new version of the API as draft to the TC as basis for further discussions on this subject. 


> 2014 March - Public Comment Questions (Plans, Instance Counts, and linking SW Nodes) 
> -------------------------------------------------------------------------------------
>
>                 Key: TOSCA-172
>                 URL: https://tools.oasis-open.org/issues/browse/TOSCA-172
>             Project: OASIS Topology and Orchestration Specification for Cloud Applications (TOSCA) TC
>          Issue Type: Bug
>          Components: Profile-YAML, Spec - Simple Profile
>    Affects Versions: OASIS Standard v1.0
>            Reporter: Paul Lipton 
>
> We are going to develop a TOSCA engine as part of an applications orchestrator service.
> While diving into the details we’ve seen that the Plan section is defined in high level at the XML TOSCA version and doesn’t appears in the simple Profile YAML version.
> Few question about that:
> 1.	What is expected from a TOSCA engine implementation when a Plan is not presented in the service template DSL? 
> a.	Should the engine understand the “plan” (e.g. the order to execute node interfaces action) from the service template topology and dependency graph? 
> 2.	Is the Plan expected to be added to the simple profile YAML version sometime?
> 3.	Can you please point me to the latest stuff related to TOSCA Plans?
> In addition to the below, some more comments:
> 1.	How should one configure an initial instance count? For example, start with 3 VM that host 3 App Servers nodes (even when there is no scaling policy at all). 
> 2.	When linking two software nodes (MySQL, Monit) to the same Compute node (VM) – does it mean that the engine can choose whether to place them on the same VM instance or to place them on separate VMs that were created based on the same Compute node? How can a user choose?
>  3.	When node A uses get_property(B, ip) – How the engine should select the correct instance of B? It is simple if A and B ratios are 1:1 or N:1 but it is unclear if the ratio is N:M.



--
This message was sent by Atlassian JIRA
(v6.1.1#6155)