Web Services Endpoint Management
Architecture Requirements Draft
Contributors
Heather
Kreger, IBM (kreger@us.ibm.com)
Mark Potts,
Talking Blocks (mark.potts@talkingblocks.com)
Igor Sedukhin,
Computer Associates (igor.sedukhin@ca.com)
Hao He,
Thomson (hao.he@thomson.com.au)
Zulah Eckert,
Hewlett Packard (zulah_eckert@hp.com)
Yin-Leng
Husband, Hewlett Packard (Yin-Leng.Husband@hp.com)
Document History
February 12, 2003 – Heather Kreger, extracted this document from the
MTF Working Draft
February 19, 2003 – Heather Kreger
accepted all changes from MTF Editing calls 2/12-2/19.
February 26, 2003 – Heather Kreger,
edited glossary based on MTF call.
February 28, 2003 – Heather Kreger,
edited based on Igor Sedukhin’s edits.
Table of Contents
1.3.1 Management
Capabilities Categories
3.1 Management Capabilities for all elements
3.1.1.4.1 Service State Change Events
3.1.1.4.2 Request Processing Events
3.1.1.7 Discovery
Requirements
3.2 Manageability
Requirements for Web Service Architecture Elements
3.2.1 Web
Service Endpoint Manageability Requirements
3.2.1.1 Identification
Requirements
3.2.1.2 Configuration
Requirements
3.2.1.4.1 For Service Endpoints
3.2.1.5 Operations
Requirements
The W3C Web Services Architecture Working Group has
been formed to document the Web Services Architecture. Enough members of the
Working Group felt that it was very important to define the manageability
characteristics of the architecture along side the architecture itself. To that
end, the following Goals, Requirements, and Critical Success factors were added
to the Web Services Architecture Requirements document.
This paper is a draft of the architectural
satisfaction of those requirements. The contents of this document should be
folded into the main Web Services Architecture draft (http://www.w3.org/TR/ws-arch/
). This draft not intended to ‘stand alone’ and independent of the Web Services
Architecture document.
We would like this proposal to be included as a
subsection in the Management Properties section of the Web Services
Architecture.
For convenience, the Manageability Goals from the
Requirements document (http://www.w3.org/TR/wsa-reqs
) are reiterated here:
D-AG007 Management and
Provisioning
The standard reference
architecture for Web Services must provide for a manageable, accountable and
organized environment for Web Services operations..
Critical success factors
and requirements for this goal:
D-AC018 The Web Services
Architecture must enable the management and provisioning of Web Services
D-AC018
The Web Services Architecture must enable the management and provisioning
of Web Services
o
AC018.1 Ensure that
implementations of the Web Services Architecture are manageable.
§
AR018.1.1 Define a base set
of standard metrics for architectural components and their interactions
accompanied by guidelines for measurement.
§
AR018.1.2 Define a base set
of standard management operations for Web Services Architecture
implementations. Management operations includes, but is not limited to, support
for configuration control and lifecycle control.
§
AR018.1.3 Define a base set
of management events to be issued by the Web Services Architecture
implementation.
§
AR018.1.4 Define a standard
methodology for accessing management capabilities from the Web Services
Architecture implementation.
o
AC018.2 Ensure that
implementations of the Web Service instances are manageable.
§
AR018.2.1 Define how a web
service should expose web service specific metrics, configuration, operations,
and events.
§
AR018.2.2 Support the
discovery of web service management capabilities.
§
AR018.2.3 Define a standard
methodology for accessing management capabilities of a Web Service through the
Web Services Architecture implementation.
o
AC018.3 Ensure that at
least the following types of management aspects are supported: Resource
Accounting, Usage Auditing and Tracking, Performance Monitoring, Availability,
Configuration, Control, Security Auditing and Administration, and Service Level
Agreements.
As a result of these Goals and Requirements, we have
identified the scope of this work to be defining the architecture necessary to
make a Web service architecture implementation and a Web service implementation
manageable. In order for the Web service architecture to be manageable, each of
the elements of the architecture must be manageable. This submission defines
only the requirements for the Web service endpoint.
The management architecture must define the
requirements for the minimum, basic information, operations, events, and
behaviors that a Web services architectural element must support in order to be
called manageable. Not all elements may be explicitly manageable. Not all implementations of Web services
architectural elements must be manageable. Support of this manageable Web
services architecture by implementations of the Web services architecture is highly
recommended, but not required.
Security administration and security management are
important aspects of management. These aspects are being addressed by other
standards groups and will not be addressed by this draft. The exception to this
is the requirement to support association of security administration WSDL with
the functional service WSDL.
This
architecture applies to the instrumentation of manageable Web Services. It does
not prescribe how the management capabilites are used by management systems.
For example, policies could be defined an implemented via management
capabilities of Web services, although this architecture does not prescribe how
to define and enforce those policies.
The following management
capabilities categories must be defined for each manageable entity:
In
addition to defining the information to be exposed by a manageable element,
this architecture must define a standard means to access the management
capabilities of the manageable element.
Finally, it must be possible for the manageability
capabilities and access to those capabilities to be discovered. Hence we need
to define discovery of managable elements, manageability capabilities, and
relationships.
Management
Systems – This architecture will not define what management systems should be
defined to manage the Web services. Nor will it define how they should be
implemented nor the way they will use the management capabilities. However,
this specification may mention such systems as part of a scenario or use case.
Service distribution/installation/deployment – This
architecture will not define how Web service component implementations are
distributed, installed or deployed into any system or set of systems.
Access rights and control – This architecture will not define the policies
(access control, trust, etc.) that govern management information flow.
Mapping of requirements to an XML Schema or WSDL
portType – This architecture will not define an explicit XML Schema or
portTypes to represent the informational requirements.
We are
defining the sufficient set of management capabilities for the architectural
element Web services endpoint.
Manageability implies the existence of a
sufficient set of management capabilities such that an entity is manageable
Manageable implies that an entity can be managed by
a management system
Management capabilities includes
identification, configuration, metrics, status, operations, and events offered
by manageable entities for management purposes
Management is the utilization of the
management capabilities by the management system.
Managed implies that an entity is actively
being managed by a management system
Manageability Interface is that interface
through which management capabilities are offered.
Management
endpoint is the Web
services endpoint offering the manageability interface for management purposes.
This section defines the basic management
capabilities, access, and discovery requirements. Management capabilities
includes: identification, status, configuration, metrics, operations, and
events.
All of the management capabilities must be
expressible using the XML Information set (http://www.w3.org/TR/xml-infoset/ ).
Manageable elements of the Web services Architecture
are identifiable by a URI.
The description of the management capabilities for a
manageable element is identifiable by a URI.
Configuration mechanisms that are common for each
type of manageable element [e.g. Web service endpoint] should conform to the
Web services architecture [e.g. description and interaction]. Configuration for
a manageable element, beyond the common configuration, should be defined by an
administrative interface. Other mechanisms to configure elements of the Web
services architecture exist, but are not in scope of this document.
Lifecycle and state diagrams are defined by the Web
Services Architecture based on the submission from the Management Task Force: http://www.w3.org/2002/ws/arch/2/11/W3C.MTF.ServiceLifecycle.20021111_clean.htm.
Status is information about the current state of the managed element.
The status of a managed element must be available
through a manageability interface.
For a manageable element there are two classes of
events: Service State Changed and Request Processing events.
Service state change events occur whenever lifecycle
state transitions happen as defined by the WSA draft. The service state change
event description should include the previous state and the transition time.
Optionally there may be events from the start of a transition.
Request Processing Event descriptions provide
information for management systems and can be used to calculate many of the
metrics. However, manageable components are not required to use these events to
calculate metrics or unconditionally disseminate them to management systems. In
busy environments, these kinds of events can create a significant amount of
overhead and implementations should take that into consideration.
A request processing event description indicates
that the state of a request has been changed and should include the previous
state and the transition time. The event may also include any context
associated with the request, reply, or failure message and any part or the
complete content of these messages.
A managed element should be capable of producing
notifications (deliverable descriptions of these events) such that they are
available to a management system.
‘Metrics’ are raw atomic, unambiguous, information,
e.g. number of invocations. This can be contrasted with ‘Measurements’ that are
calculated with a formula based on metrics, e.g. Average response time during
the last hour of execution.
The metrics requirements do not enforce any
implementation pattern. A managed element should allow any available metrics
and measurements to be reported according to configurable time intervals, such
as cumulative, sliding window, and interval. A managed element must declare
which interval types are supported.
Management capabilities must be available in a
manner conformant to Web Services architecture.
Discovery
has three requirements to be satisfied, discovery of the manageable element,
and discovery of the management capabilities for a manageable element, and
discovery of relationships.