Requirements for Management Using Web Services

["KUMAR,PANKAJ (HP-Cupertino,ex1)" <pankaj_kumar@hp.com>]

Hi WSDM-TC Members,

To continue the discussion initiated by last week's presentation, 
we would like to submit the attached writeup as starting point for 
further discussion on "Management Using Web Services" 
requirements. A subsequent submission will include a writeup on
"Management Of Web Services" requirements.

Winston, Heather,

Please add these documents to the TC agenda.

Best Regards, <<MUWS-Req.txt>> 
Pankaj Kumar
Web Services management Organization,
HP OpenView, HP.
Tel: 1-408-447-4571
Requirements -- Management Using Web Services
=============================================

This writeup explains the need to have a standard management 
protocol for managing computing resources using Web Services, 
refereed to as MUWS, and lists basic requirements that should 
be met by such a protocol. 

Following terminology is used to state the requirements:

Managed Resource -- Any entity, a piece of h/w, s/w or a 
logical resource that is capable of being managed.
Manager -- Software that manages one or more Managed Resources.
Agent -- Software that facilitates the interaction between the 
Manager and the Managed Resources.

Why A New Management Protocol?
------------------------------

The motivation to use Web Services as the integration 
technology stems from a desire to:

  + allow management solutions to benefit from the distributed, 
    dynamic, loosely-coupled, secured (and soon reliable) 
    architecture provided by web services technologies.
  + allow Software vendors expose the manageability of their software 
    in a uniform and standard way.
  + allow out-of-box manageability of complex software systems.
  + allow vendors and users of these software systems to develop 
    tools based on open and inter-operable standards.
  + allow management of Web Services using Web Services.
    
Requirements
------------

Management Interface Requirements
---------------------------------
1. It should support management of Web Services in most natural way.
2. It should support management of any Managed Resource.
3. It should be able to uniquely identify a managed Resource and
   allow a manager to access other identification information such
   as vendor, version, operator etc.
4. It should support long-lived Managed Resources as well as short-lived 
   Managed Resources.
5. It should be possible to get current status of a Managed Resource
   and other related information. For example, for a Managed Resource
   in error condition, it should be possible to get more details.
7. It should support the notion of Management Information Models
   without defining or assuming specific models. As a corollary,
   it should support existing models defined by other standards.
8. At the minimum, it should support models with
     + typed, read-only and read-write attributes of a Managed
       resource. These attributes should be able to support various
       kinds of metrics.
     + synchronous operations on a Managed Resource taking typed
       parameters and returning typed return values.
     + asynchronous one-way notifications.
     + binary relationships among Managed Resources. It should
       be possible to have relationship with Managed Resources
       not managed by this management protocol.
9. Asynchronous, one-way event support should allow
     + A manager to receive notification of certain types only.
     + notifications when instance model changes (new Managed
       Resource added, existing one deleted, relationship changed,
       etc.)
     + Manager to control whether to get notification asynchronously
       or pull them at periodic intervals)
10. It should be possible for an Agent and Manager to communicate
    across a firewall.
11. An Agent should support multiple Managers and vice-versa.
12. A manager should be able to discover Managed Resources without
    going through a central registry.
13. It should be possible to have gateway components that act as
    both Agents and Managers.
14. It should be possible to support the management protocol without
    using an agent (the Managed Resource implements the management
    interface ).
15. It should be possible to use this protocol in scenarios where
    an enterprise out-sources management functions.
    
Some of the above requirements may be needed outside of management
interfaces and are best supported by Web Services Architecture. These
are listed below:
    
      Web Services Architecture Requirements
      --------------------------------------
      3. Web Services Identification
      9. Support for events
      12. Discovery mechanisms

Standards Compliance
--------------------
1. Communication between Manager and Agent must support SOAP over
   HTTP.
2. Management interface of a Managed Resource must be exposed
   using WSDL.
3. The management protocol must be WS-I compliant.
4. Should not depend on standards for which implementations are
   not widely available AND which cannot be easily implemented by
   implementers of this standard.

Security
---------
1. It must support authentication of the Manager by the Agent.
2. It must support authentication of the Agent by the Manager.
3. It must support integrity and confidentiality of management
   messages being exchanged between Manager and the Agent.
4. An agent must be able to apply access control to Managed
   Resource at the appropriate granularity level. Any unauthorised
   access by a manager must be reported as such.
5. It should be possible for an operator to enable/disable security
   features at the Agent.
6. A Manager should be able to communicate with Agents with varying
   degrees of enabled security features.
   
Scalability
-----------
1. It should be possible to off-load certain kinds of processing/
   filtering at Agent to reduce network traffic.
2. It should be possible to apply an operation on more than one
   Managed Resource without making a separate request for each
   Managed Resource.
3. A Manager should be able to support a large number of
   Managed Resources.
4. A Manager should be able to retrieve multiple attribute values
   from one or more Managed Resources without causing too much
   network traffic.
   
Extensibility
-------------
1. It should be possible to apply the management protocol to
   different domain specific models.
2. It should be possible to add model specific attributes.
3. It should be possible to add model specific operations.
4. It should be possible to  add model specific event types.
5. It should be possible to extend event notification fields
   as per the requirement of the model.
6. It should be possible to add relationship types.
   
Interoperability
----------------
1. It should be possible for a compliant Manager to work with
   a compliant Agent in a predictable way.

Internationalization
--------------------
1. The protocol should support I18N.
   
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