RE: [tosca] Event Interface Proposal

Calin,

Responses below:

1. For #1, of course , APIs are exposed to invoke notifications, However, I am referring to cases where the source of notification, for e.g,. bash scripts (with infinite loop) that check some parameters on VM, can be associated with the notification in the model.

notifications: #event_interfaces in the original proposal

key_reports:

availability_report:

outputs:

value: [ TOPOLOGY, monitor, ubuntu_availability ]

implementation: #new

primary: alarm_processing # new

event_types:

- failure_monitoring

fault_report:

outputs:

value: [ SELF, monitor, failure ]

implementation: #

primary: alarm_processing # new

dependencies: #

- prober #

event_types:

- failure_processing

2. The use of TOPOLOGY keyword is for reading attributes at the topology level. In your proposal, I see examples related to availability_monitoring or failure_monitoring. Consider a VNF described using a topology template. While the availability of VDUs can be read through SELF keyword, it may be needed to check the availability of the entire VNF. In these cases, the TOPOLOGY keyword can be uaed on similar lines as SELF keyword.

Let me know your thoughts on this.

Regards,

Priya

From: Calin Curescu [mailto:calin.curescu@ericsson.com]
Sent: Tuesday, September 04, 2018 6:47 PM
To: Chris Lauwers; Priya T G
Cc: tosca@lists.oasis-open.org
Subject: Re: [tosca] Event Interface Proposal

Chris: Sure.

However the reader should be aware of the important difference here:

The normal operation is invoked internally from the orchestrator during LCM workflows
The notification is invoked any time by the external world.

Then I would lobby to introduce in the interface definition the keyword âoperationsâ to gather the operations symbolic name and the keyword ânotificationsâ to gather the notifications symbolic names.

Anyway the former is already required since not having it clashes with the âinputsâ section of the interfaces (see matt comment in section 3.7.5.2. Grammar of Interface Type Definitions).

Priya: please fins some inline comments in your text below.

Btw, I think the ânotificationâ name fits very well, so I will use that from now on.

BR,

/Calin

From: Chris Lauwers <lauwers@ubicity.com>
Date: Monday, 3 September 2018 at 07:10
To: Priya T G <priya.g@netcracker.com>, Calin Curescu <calin.curescu@ericsson.com>
Cc: "tosca@lists.oasis-open.org" <tosca@lists.oasis-open.org>
Subject: RE: [tosca] Event Interface Proposal

I like these concepts, but Iâd like to avoid having to create new âinterface typesâ just for events or notifications. We already have too many types of types.

Canât we just add a notifications or events keyname to the existing interface definitions?

Chris

From: Priya T G <priya.g@netcracker.com>
Sent: Friday, August 31, 2018 6:44 AM
To: Calin Curescu <calin.curescu@ericsson.com>; Chris Lauwers <lauwers@ubicity.com>
Cc: tosca@lists.oasis-open.org
Subject: RE: [tosca] Event Interface Proposal

Calin,

Thanks for responding. Clarifications below:

I am actually referring to cases where artifacts associated with a node template could invoke the event interfaces, consider examples of scripts that could notify the Orchestrator upon some occurrence of some events. In such cases, there should be a way to describe this artifact within the scope of node template.

What I mean is that anybody can invoke the notifications, the association with the artifact is not useful since we are just exposing an API here.

Regarding TOPOLOGY keyword, in the current TOSCA Simple profile specification there are two cases how attribute is assigned a value from operation:

a. Attribute - by means of get_operation_ouput function in attribute definition/assignment

b. Operation â by means of output section

Topology attributes can be filled through substitution mapping. We could adhere to a common approach and provide possibility to fill topology attributes through operation (or event) and read topology attribute values from node instances inside topology.

In the case of substitution mapping, the properties of the substituted node are mapped to the inputs of the substitution topology template, and the outputs of the topology template are mapped back to the attributes of the substituted node.

So we could use the outputs here, where they could get assigned using get_attribute from a specific node. Then we do not need the TOPOLOGY keyword (and anyway there are no global attributes section of a topology template.

Let me know your views.

Regards,

Priya

From: tosca@lists.oasis-open.org [mailto:tosca@lists.oasis-open.org] On Behalf Of Calin Curescu
Sent: Wednesday, August 29, 2018 7:59 PM
To: Priya T G; lauwers@ubicity.com
Cc: tosca@lists.oasis-open.org
Subject: Re: [tosca] Event Interface Proposal

Hi Priya,

I realized I have not answered to your mail, I was hoping to discuss it all in the WG meeting before we go further. Anyway, some first thoughts on your proposals inline.

BR,

/Calin

From: <tosca@lists.oasis-open.org> on behalf of Priya T G <priya.g@netcracker.com>
Date: Tuesday, 7 August 2018 at 15:10
To: "lauwers@ubicity.com" <lauwers@ubicity.com>, Calin Curescu <calin.curescu@ericsson.com>
Cc: "tosca@lists.oasis-open.org" <tosca@lists.oasis-open.org>
Subject: [tosca] Event Interface Proposal

Hello Calin, Chris,

This is regarding the event interface proposal that was uploaded in OASIS portal recently: https://www.oasis-open.org/apps/org/workgroup/tosca/download.php/63289/EventInterface2018_06_20.docx

I believe this has not yet been discussed in TOSCA Simple Profile meetings, but is in plan for TOSCA YAML v1.3.

I have a few comments and suggestions on this:

We could embed implementation artifacts in the event_interfaces which could be responsible for triggering these events external to the Orchestrator. This is in addition to how information in such notification will be stored on node instances/topology instance attributes after it has been received.

I was thinking initially that the orchestrator will provide a couple of standard interface technologies (HTTP/REST, RPC, â) to accept these notifications, where the data model exchanged is YAML/JSON. So an external implementation would know exactly how to format data and use the API.

The only effect in the orchestrator is that attributes values are updated and specific orchestrator events are generated. The events may then trigger workflows are already defined in TOSCA, and these workflows can then call operations that artifact implementations can be attached to. If we want to have a shortcut for the latter step (i.e. not needing to set up and specify an entire workflow), Iâm more inclined that we provide an extra âcall_operationâ keyword in the definition that will call a specific operation i.e:

fault_report:

outputs:

value: [ SELF, monitor, failure ]

event_types:

- failure_processing

call_operation: #new

- SELF.alarm_processing #new

Just an alignment with common approaches like REST (when you can POST or wait for callback notification), we could rename âevent_interfaceâ as ânotificationâ

Notification is a good alternative. Letâs propose it to the group.

Introduce a new keyword âTOPOLOGYâ on similar lines as âSELFâ. This provides possibility to fill topology attributes as a result of an operation or event and provide possibility to read topology attribute values from node instances inside topology.

I donât think I understand the TOPOLOGY reference. Afaik, there are no attributes that are connected to the topology_template.

BR,

/Calin

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