Web Services Web Services Management FrameworkManagement Framework

by Umut Bultan & Gül by Umut Bultan & Gül HünerkarHünerkar

Web Services Management Web Services Management Framework (WSMF)Framework (WSMF)

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

Hewlett-Packard Hewlett-Packard & WSMF& WSMF

• WSMF is HP’s WSMF is HP’s effort to create an industry effort to create an industry standards-based platform for Web-services standards-based platform for Web-services management. management.

• WSMFWSMF is an accepted standard by OASIS is an accepted standard by OASIS ((Organization for the Advancement of Organization for the Advancement of Structured Information StandardsStructured Information Standards)), an , an international consortium focused on the international consortium focused on the development and adoption of e-business development and adoption of e-business standards for information exchange. standards for information exchange.

Advantages of WSMFAdvantages of WSMF• Current standards (eg. SNMP, CIM)

offer subset of needed functionalitymanage subset of manageable resourcesmanageability often secondary aspect in

design

• WSMF: consistent and secure management ofvarious types of resources using Web

Servicesrepresent resources as managed objectsmanage them through Web Services

TerminologyTerminology• Managed object: Managed object: A managed object is a A managed object is a

management representation of a resource. A management representation of a resource. A managed object implements one or more managed object implements one or more management interfaces to provide a means to monitor management interfaces to provide a means to monitor and/or control the underlying resource.and/or control the underlying resource.

• Management interface: Management interface: A management interface A management interface represents management capabilities of a resource. A represents management capabilities of a resource. A management interface is presented as a set of management interface is presented as a set of attributes, operations, and notifications to be attributes, operations, and notifications to be accessed through a WSDL portType.accessed through a WSDL portType.

• Interface collection: Interface collection: An An interface collection interface collection is a is a group of management interfaces that represent the group of management interfaces that represent the management capabilities of a type of managed object.management capabilities of a type of managed object.

• Event: Event: An An event event is a change in the state of a resource is a change in the state of a resource or request for processing.or request for processing.

• Notification: Notification: A notification is a message that is sent A notification is a message that is sent to or retrieved by one or more subscribers to inform to or retrieved by one or more subscribers to inform them that an event has occurred.them that an event has occurred.

TerminologyTerminology• Subscriber: Subscriber: A subscriber is an entity that is A subscriber is an entity that is

interested in selected notifications from managed interested in selected notifications from managed objects. These notifications contain information objects. These notifications contain information about the state change in a managed object.about the state change in a managed object.

• Resource: Resource: A resource is a component of a A resource is a component of a deployed environment.deployed environment.

• Relation: Relation: A relation is a type of association A relation is a type of association between two managed objects.between two managed objects.

• Relationship: Relationship: A relationship specifies two A relationship specifies two managed objects and the relation to define how managed objects and the relation to define how two specific objects are associated.two specific objects are associated.

• Model: Model: A model is a set of objects, properties, A model is a set of objects, properties, and their relationships.and their relationships.

Specification DocumentsSpecification 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.

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.

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.

Attributes and OperationsAttributes and Operations

• WSMF groups attributes and operations into six categories defined by OSI. The categories are:monitoringdiscoverycontrolperformanceconfigurationSecurity

• Attributes support different access policies read-only and read/write.

Relations and RelationshipsRelations and Relationships• A A relation relation specifies only the association specifies only the association

without the context of which objects are part without the context of which objects are part of the association. Examples are: dependsOn, of the association. Examples are: dependsOn, isDuplicatedBy, isTheSameColorAs, etc. isDuplicatedBy, isTheSameColorAs, etc.

• A A relationship relationship adds the context of the adds the context of the participants in the association. A participants in the association. A relationship relationship is an ordered association. For example, "A is an ordered association. For example, "A dependsOn B", is not the same as "B dependsOn B", is not the same as "B dependsOn A". dependsOn A".

• Think of the Think of the relation relation as a verb, one as a verb, one managed managed object object as the subject, and the other as the subject, and the other managed managed object object as the object of the as the object of the relationship relationship ..

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

WS-EventsWS-Events

• Event Producer:Event Producer: An An event producerevent producer is an is an entity which generates notifications.entity which generates notifications.

• Event Consumer:Event Consumer: An An event consumerevent consumer is a is a receiver of notifications.receiver of notifications.

• Event Broker: Event Broker: An An event brokerevent broker is an entity is an entity which routes notifications. Brokers typically which routes notifications. Brokers typically aggregate and publish events from other aggregate and publish events from other producers. An event broker can also apply producers. An event broker can also apply some transformation to the notifications it some transformation to the notifications it processes.processes.

Event Discovery Event Discovery • GetAllEventTypes() : returns the list of all GetAllEventTypes() : returns the list of all

events accesible by an event consumer events accesible by an event consumer (namely EventTypeList)(namely EventTypeList)

• GetEventType Definition(): returns the GetEventType Definition(): returns the detailled definition of an event (namely detailled definition of an event (namely EventTypeDefinitionList)EventTypeDefinitionList)

• GetEventInstanceInfo(): returns events GetEventInstanceInfo(): returns events that have happened before a subscriber that have happened before a subscriber started its subscription (namely started its subscription (namely EventInstanceInfoList)EventInstanceInfoList)

Event Discovery ExampleEvent Discovery Example

Event Notification Event Notification SubscriptionSubscription

• Subscriptions allow the notification producer Subscriptions allow the notification producer to plan and allocate resources depending on to plan and allocate resources depending on

the number of subscribersthe number of subscribersevent notification typesevent notification typesaccess modes access modes length of subscriptionslength of subscriptions

• Subscriptions have a limited duration in time. Subscriptions have a limited duration in time. For instance, it might last for an hour. This For instance, it might last for an hour. This ensures that if a subscriber went away and ensures that if a subscriber went away and forgot to cancel its subscription, resources forgot to cancel its subscription, resources would not be held indefinitely and recovered would not be held indefinitely and recovered by the event producer. Subscription can be by the event producer. Subscription can be renewed before it expires. renewed before it expires.

Event Notification Event Notification Subscription ExampleSubscription Example

Web Services Web Services Management(WSM)Management(WSM)• Application of WSMF-Foundation to

management of (resources involved in) Web Services

• Managed object types:Web ServiceWeb Services Execution Environment(hosts Web

Services)Conversation(individual view of this interaction)

• Relations:contains/contained-independs-on/dependent-oncorresponds-to

WSM RelationsWSM Relations• A WSExecutionEnvironment contains 0 to many A WSExecutionEnvironment contains 0 to many

Services Services • A Service is contained in a A Service is contained in a

WSExecutionEnvironment WSExecutionEnvironment • A Service depends on 0 to many Services A Service depends on 0 to many Services • A Service is depended upon by 0 to many A Service is depended upon by 0 to many

Services Services • A Service contains 0 or more Conversations A Service contains 0 or more Conversations • A Conversation is contained in a Service A Conversation is contained in a Service • A Conversation corresponds to one or more A Conversation corresponds to one or more

Conversations Conversations

ConclusionConclusion

• We argue that Web services technologies We argue that Web services technologies form the likely future platform for form the likely future platform for management since it is language and management since it is language and platform independent, interoperable, platform independent, interoperable, industry momentum and it hides industry momentum and it hides implementation. implementation.

• Currently there is no standard for Currently there is no standard for managing Web Services. Further work is managing Web Services. Further work is needed.needed.