Web Services Management Framework

1. Web Services Management Framework by Umut Bultan & Gül Hünerkar

2. Web Services Management Framework (WSMF) • Web Services Management Framework is a management framework to provide a consistent and secure mechanism based on Web services for managing various types of resources, including Web services themselves.

3. Hewlett-Packard & WSMF • WSMF is HP’s effort to create an industry standards-based platform for Web-services management. • WSMFis an accepted standard by OASIS (Organization for the Advancement of Structured Information Standards), an international consortium focused on the development and adoption of e-business standards for information exchange.

4. Advantages of WSMF • Current standards (eg. SNMP, CIM) • offer subset of needed functionality • manage subset of manageable resources • manageability often secondary aspect in design • WSMF: consistent and secure management of • various types of resources using Web Services • represent resources as managed objects • manage them through Web Services

5. Terminology • Managed object: A managed object is a management representation of a resource. A managed object implements one or more management interfaces to provide a means to monitor and/or control the underlying resource. • Management interface: A management interface represents management capabilities of a resource. A management interface is presented as a set of attributes, operations, and notifications to be accessed through a WSDL portType. • Interface collection: An interface collection is a group of management interfaces that represent the management capabilities of a type of managed object. • Event: An event is a change in the state of a resource or request for processing. • Notification: A notification is a message that is sent to or retrieved by one or more subscribers to inform them that an event has occurred.

6. Terminology • Subscriber: A subscriber is an entity that is interested in selected notifications from managed objects. These notifications contain information about the state change in a managed object. • Resource: A resource is a component of a deployed environment. • Relation: A relation is a type of association between two managed objects. • Relationship: A relationship specifies two managed objects and the relation to define how two specific objects are associated. • Model: A model is a set of objects, properties, and their relationships.

8. Specification Documents • WSMF-Foundation defines the base framework for management using Web services. • WS-Events defines the Web services based event notification mechanism. This mechanism is used by WSMF-Foundation. • WSMF-Web Services Management defines the model for management of Web services.

9. Managed Object and Management Interfaces • A managed object provides management capabilities by implementing management interfaces. • Management interfaces are grouped into collections of interfaces to describe a group of management capabilities about a specific type of managed object.

10. Managed Object and Management Interfaces(Cont) • A management interface have: • Attributes: The set of properties representing information about a managed object. • Operations: The set of functions that can be provided to support the management of a managed object. • Notification types: The set of events and state changes that can be reported by a managed object • Management interfaces are mapped to WSDL portTypes.

11. Attributes and Operations • WSMF groups attributes and operations into six categories defined by OSI. The categories are: • monitoring • discovery • control • performance • configuration • Security • Attributes support different access policies • read-only and read/write.

12. Relations and Relationships • A relation specifies only the association without the context of which objects are part of the association. Examples are: dependsOn, isDuplicatedBy, isTheSameColorAs, etc. • A relationship adds the context of the participants in the association. A relationship is an ordered association. For example, "A dependsOn B", is not the same as "B dependsOn A". • Think of the relation as a verb, one managed object as the subject, and the other managed object as the object of the relationship .

13. Events and Notifications • There are two modes to get notifications: • In the push mode, when an event occurs, the managed object sends a notification to the subscribers to inform them of a change of state. • In the pull mode, the subscriber issues calls to the managed object to request all the notifications that happened since the last pull call. • In both modes, a subscribe call is used to register an interest for one or more event types

14. WS-Events • Event Producer: An event producer is an entity which generates notifications. • Event Consumer: An event consumer is a receiver of notifications. • Event Broker: An event broker is an entity which routes notifications. Brokers typically aggregate and publish events from other producers. An event broker can also apply some transformation to the notifications it processes.

15. Event Discovery • GetAllEventTypes() : returns the list of all events accesible by an event consumer (namely EventTypeList) • GetEventType Definition(): returns the detailled definition of an event (namely EventTypeDefinitionList) • GetEventInstanceInfo(): returns events that have happened before a subscriber started its subscription (namely EventInstanceInfoList)

16. Event Discovery Example

17. Event Notification Subscription • Subscriptions allow the notification producer to plan and allocate resources depending on • the number of subscribers • event notification types • access modes • length of subscriptions • Subscriptions have a limited duration in time. For instance, it might last for an hour. This ensures that if a subscriber went away and forgot to cancel its subscription, resources would not be held indefinitely and recovered by the event producer. Subscription can be renewed before it expires.

18. Event Notification Subscription Example

19. Web Services Management(WSM) • Application of WSMF-Foundation to management of (resources involved in) Web Services • Managed object types: • Web Service • Web Services Execution Environment(hosts Web Services) • Conversation(individual view of this interaction) • Relations: • contains/contained-in • depends-on/dependent-on • corresponds-to

21. WSM Relations • A WSExecutionEnvironment contains 0 to many Services • A Service is contained in a WSExecutionEnvironment • A Service depends on 0 to many Services • A Service is depended upon by 0 to many Services • A Service contains 0 or more Conversations • A Conversation is contained in a Service • A Conversation corresponds to one or more Conversations

22. Conclusion • We argue that Web services technologies form the likely future platform for management since it is language and platform independent, interoperable, industry momentum and it hides implementation. • Currently there is no standard for managing Web Services. Further work is needed.

23. Any Questions???