9613 2010-04-28 22:19:47 +0000 Eventing: Support WS-Management's persistent subscriptions 2010-07-28 09:11:20 +0000 1 1 1 Unclassified WS-Resource Access Eventing LC All All CLOSED REMIND externalComments P2 enhancement --- 1 gilbert.pilz gilbert.pilz dug tom public-ws-resource-access-notifications oldest_to_newest 35293 0 gilbert.pilz 2010-04-28 22:19:47 +0000 The WS-Man WG has identified the need for “persistent subscriptions” in WS-Eventing. A “persistent subscription” is a subscription that is guaranteed (by the Event Source) to survive such occurrences as the shutdown/restart of the Event Source's container, the shutdown/restart of the Event Source's VM, or the reboot of the device hosting the Event Source. Although any Event Source is allowed to provide such a quality of service in the current specification, the important aspect of this feature is the Subscribers knowledge of this guarantee. It is the opinion of the WS-Man WG that this feature is sufficiently general as to warrant inclusion in the base specification. --- Proposal: 1. Add an optional element to the wse:Subscribe element (e.g. “wse:Persistent”) that indicates that the Subscriber is requesting a persistent subscription. 2. Create a new fault that MUST be generated by the Event Source if that Event Source is unable/unwilling to create a persistent subscription in the face of a request to do so. 3. Add a parameter to the wse:EventSource assertion that indicates the endpoints ability to create persistent subscriptions. 4. Define a mechanism to allow a client to specify whether the request should be performed with or without the use of this feature in a way similar to the way mustUnderstand works. [1] http://www.dmtf.org/standards/published_documents/DSP0226_1.1.pdf 35576 1 bob 2010-05-11 21:15:20 +0000 Add to end of sec 4.5 ", if possible" add to the end of the 2nd para in sec 4 .. via a SubscriptionEnd message if an EndTo was present in the Subscribe message. 35579 2 tom 2010-05-11 21:40:27 +0000 Proposed WG Response to Originator: WS-RA WG Response to originator of Bug 9613: Eventing: Support WS-Management's persistent subscriptions The WS-RA WG considered the WS-Management Last Call comment, Logged as Bug 9613. Persistence is a difficult topic. For example, we do not understand why an event source which can handle persistence of subscriptions would not persist all of its subscriptions. We see this as a quality of service concern, and after due consideration, we have decided that ways to accommodate such concerns are domain specific and outside the scope of the WS-RA work. These kind of Quality of service concerns should be dealt with in an implementation or domain specific manner. For example, a management workstation could be able to determine the kind of event sources it is dealing with, and have a table in its own state to know whether each event source supports persistence of its subscriptions. However, our discussions made us realize that the spec needs a clarification regarding the possibility of an event source / subscription manager going down before it can send a subscription End message to an EndTo epr. We agreed to close this Bug with the following changes to the WS-Eventing specification: Add “, if possible.” to the end of the first paragraph of 4.5 Subscription End add the following to end of 2nd para in section 4: “via a SubscriptionEnd message if an EndTo was present in the Subscribe message.” 36052 3 bob 2010-06-08 17:41:44 +0000 2010-06-01 Discussed with Rich Landau of Dell who attended as an observer. WG confirmed close with no action after arguments concerning difficulty of defining persistence in a non-domain specific manner.