Cloud Data Management Interface (CDMI) Media Types
draft-cdmi-mediatypes-07

Internet Engineering Task Force                           K. Sankar, Ed.
Internet-Draft                                                     Cisco
Intended status: Informational                                  A. Jones
Expires: July 11, 2011                                              SNIA
                                                         January 7, 2011

           Cloud Data Management Interface (CDMI) Media Types
                        draft-cdmi-mediatypes-07

Abstract

   This document describes several Internet media types defined for the
   Cloud Data Management Interface (CDMI) by the Storage Networking
   Industry Association (SNIA).  The media types are:

   o  application/cdmi-domain

   o  application/cdmi-capability

   o  application/cdmi-container

   o  application/cdmi-object and

   o  application/cdmi-queue

Status of this Memo

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   This Internet-Draft will expire on July 11, 2011.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   This document is subject to BCP 78 and the IETF Trust's Legal
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   (http://trustee.ietf.org/license-info) in effect on the date of
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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Requirements Language  . . . . . . . . . . . . . . . . . .  3
   2.  Cloud Data Management Domain and its Relevance . . . . . . . .  3
   3.  Processing Guidelines  . . . . . . . . . . . . . . . . . . . .  4
     3.1.  Type : application/cdmi-object . . . . . . . . . . . . . .  4
     3.2.  Type : application/cdmi-container  . . . . . . . . . . . .  4
     3.3.  Type : application/cdmi-domain . . . . . . . . . . . . . .  5
     3.4.  Type : application/cdmi-capability . . . . . . . . . . . .  5
     3.5.  Type : application/cdmi-queue  . . . . . . . . . . . . . .  5
   4.  Transport Considerations . . . . . . . . . . . . . . . . . . .  5
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  6
     5.1.  Media Type application/cdmi-capability . . . . . . . . . .  6
     5.2.  Media Type application/cdmi-container  . . . . . . . . . .  7
     5.3.  Media Type application/cdmi-domain . . . . . . . . . . . .  8
     5.4.  Media Type application/cdmi-object . . . . . . . . . . . .  9
     5.5.  Media Type application/cdmi-queue  . . . . . . . . . . . .  9
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 10
     6.1.  Confidentiality and Integrity  . . . . . . . . . . . . . . 11
     6.2.  Access Control . . . . . . . . . . . . . . . . . . . . . . 11
     6.3.  Audit  . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     6.4.  JSON Security Considerations . . . . . . . . . . . . . . . 11
     6.5.  Executable/active content  . . . . . . . . . . . . . . . . 11
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 12
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 12
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12

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1.  Introduction

   The Cloud Data Management Interface (CDMI) [CDMI-1] developed by the
   Storage Networking Industry Association (SNIA) is the functional
   interface that applications will use to create, retrieve, update and
   delete data elements from the cloud.  As part of this interface, the
   client will be able to discover the capabilities of the cloud storage
   offering and use this interface to manage containers and the data
   that is placed in them.  In addition, metadata can be set on
   containers and their contained data elements through this interface.

1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.  Cloud Data Management Domain and its Relevance

   A storage cloud is a storage service hosted either on-premise or off-
   premise, across a network.  An important part of the cloud model, in
   general, is the concept of a pool of resources that are drawn from,
   on demand, in small increments (smaller than what one would typically
   purchase by buying equipment).  By abstracting data storage behind a
   set of service interfaces and delivering it on demand, a wide range
   of actual offerings and implementations are possible.  The only type
   of storage that is excluded from this definition is that which is
   delivered, not based on demand, but on fixed capacity increments.

   The CDMI defines a set of functional interfaces (data paths) and
   management interfaces (control paths) to create, retrieve, update,
   and delete data elements from a storage cloud.  Another important
   concept in this standard is that of metadata.  When managing large
   amounts of data with differing requirements, metadata is a convenient
   mechanism to express those requirements in such a way that underlying
   data services can differentiate their treatment of the data to meet
   those requirements.  CDMI also defines an extensible metadata system
   for storage clouds.

   As part of the CDMI interface, the client will be able to discover
   the capabilities of the cloud storage offering and to use this
   interface to manage containers and the data that is placed in them.
   In addition, system metadata can be added to containers and their
   contained data elements through this interface.

   The hierarchy that CDMI defines is as follows:

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   o  The basic element of storage is an object

   o  Objects are stored in a container hierarchy

   o  CDMI also defines an object, called a queue, which has special
      properties for in-order, first in, first-out creation and fetching
      of queue objects, similar to a container of data objects.

   o  A cloud offering can also support domains, which allow
      administrative ownership to be associated with stored objects.
      Domains can also be hierarchical, allowing for corporate domains
      with multiple children domains for departments or individuals.
      The domain concept is also used to map Access Control Lists (ACLs)
      to principals as well as to aggregate usage data that is used to
      bill, meter, and monitor cloud usage.  (Note: The CDMI "domain"
      defined here is not a DNS domain name as specified in RFCs 1023
      and 1024.)

   o  Finally, a capabilities resource and associated URI [RFC3986]
      allows a client to discover the capabilities of the offering and
      its implementation of CDMI.

3.  Processing Guidelines

   This section summarizes the processing of each media type.  This
   document provides only the essential information.  The CDMI
   specification [CDMI-1] which has more details and appropriate
   examples, is the final authority on the processing aspects.

3.1.  Type : application/cdmi-object

   A CDMI object is the basic storage element in a CDMI system and is
   analogous to a file within a filesystem.  The object is represented
   in the CDMI interface in JSON format [RFC4627] (see the JSON web site
   at [JSON-1] for general information about JSON).  Each data object
   has a set of well-defined fields that includes a single value and
   optional metadata.  The implementations are free to store the data in
   any form they choose, but the application/cdmi-object SHOULD be
   represented in the CDMI interface as defined in section 8 of the CDMI
   specification [CDMI-1].

3.2.  Type : application/cdmi-container

   A container objects is the the fundamental grouping of stored data
   within CDMI and is analogous to a directory within a filesystem.
   Each container has zero or more child objects and a set of well-
   defined fields that includes standardized and custom metadata.  A

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   container can include other containers similar to sub-directories in
   a filesystem.  The implementations are free to represent the
   container in any form they choose, but the application/cdmi-container
   SHOULD be represented in the CDMI interface as defined in section 9
   of the CDMI specification [CDMI-1].

3.3.  Type : application/cdmi-domain

   Domain objects represent the concept of administrative ownership of
   stored data within a CDMI storage system.  A CDMI offering may
   include a hierarchy of domains that provide access to domain-related
   information within a CDMI context.  This domain hierarchy is a series
   of CDMI objects that correspond to parent and child domains, with
   each domain corresponding to logical groupings of objects that are to
   be managed together.  Section 10 of the CDMI specification [CDMI-1]
   details the information content, representation and processing on
   domain objects.

3.4.  Type : application/cdmi-capability

   Capability objects form a special class of container object that
   allows a CDMI client to discover what subset of the CDMI standard is
   implemented by a CDMI provider.  For each URI in a CDMI system, the
   set of interactions that the system is capable of performing against
   that URI is described by the presence of named "capabilities".  Each
   capability present for a given URI indicates what functionality the
   cloud storage system will allow against that URI.  Capabilities are
   always static.  Section 12 of the CDMI specification [CDMI-1] details
   the representation and processing of capability objects.

3.5.  Type : application/cdmi-queue

   Queues are a special class of container object and are used to
   provide first-in, first-out access when storing and retrieving data.
   A queue writer PUTs objects to the queue, and a queue reader GETs
   objects from the queue, acknowledging the receipt of the last object
   that it received.  Queuing provides a simple mechanism for one or
   more writers to send data to a single reader in a reliable way.  If
   queues are supported by the cloud storage system, cloud clients
   create the queue objects by using the same mechanism used to create
   data objects.  Section 11 of the CDMI specification [CDMI-1] details
   the operations and processing of queue objects.

4.  Transport Considerations

   The CDMI operates over HTTP [RFC2616] and does not make sense outside
   the HTTP realm.  We do not expect the CDMI to operate over other

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   protocols, nor to use a transport protocol, such as TCP (RFC 793),
   directly.

5.  IANA Considerations

   This memo includes a request to IANA to register the following media
   types :

   o  application/cdmi-domain

   o  application/cdmi-capability

   o  application/cdmi-container

   o  application/cdmi-object and

   o  application/cdmi-queue

5.1.  Media Type application/cdmi-capability

   Type name: application

   Subtype name: cdmi-capability

   Required parameters: none

   Optional parameters: none

   Encoding considerations: Assumes that the representation is always
   UTF-8 as defined in [RFC3629] and 8bit as defined in [RFC4288].

   Security considerations: See Section 6 of draft-cdmi-mediatypes-07

   Interoperability considerations: none

   Published specification: draft-cdmi-mediatypes-07

   Applications that use this media type: Implementations of the Cloud
   Data Management Interface (CDMI) defined by the Storage Networking
   Industry Association (SNIA)

   Additional information:

      Magic number(s): n/a

      File extension(s): .cdmia

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      Macintosh file type code(s): TEXT

   Person and email address to contact for further information: Arnold
   Jones arnold.jones@snia.org

   Intended usage: COMMON

   Restrictions on usage: none

   Author: SNIA Cloud Storage Initiative cloudtwg@snia.org

   Change controller: SNIA Cloud Storage Initiative cloudtwg@snia.org

5.2.  Media Type application/cdmi-container

   Type name: application

   Subtype name: cdmi-container

   Required parameters: none

   Optional parameters: none

   Encoding considerations: Assumes that the representation is always
   UTF-8 as defined in [RFC3629] and 8bit as defined in [RFC4288].

   Security considerations: See Section 6 of draft-cdmi-mediatypes-07

   Interoperability considerations: none

   Published specification: draft-cdmi-mediatypes-07

   Applications that use this media type: Implementations of the Cloud
   Data Management Interface (CDMI) defined by the Storage Networking
   Industry Association (SNIA)

   Additional information:

      Magic number(s): n/a

      File extension(s): .cdmic

      Macintosh file type code(s): TEXT

   Person and email address to contact for further information: Arnold
   Jones arnold.jones@snia.org

   Intended usage: COMMON

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   Restrictions on usage: none

   Author: SNIA Cloud Storage Initiative cloudtwg@snia.org

   Change controller: SNIA Cloud Storage Initiative cloudtwg@snia.org

5.3.  Media Type application/cdmi-domain

   Type name: application

   Subtype name: cdmi-domain

   Required parameters: none

   Optional parameters: none

   Encoding considerations: Assumes that the representation is always
   UTF-8 as defined in [RFC3629] and 8bit as defined in [RFC4288].

   Security considerations: See Section 6 of draft-cdmi-mediatypes-07

   Interoperability considerations: none

   Published specification: draft-cdmi-mediatypes-07

   Applications that use this media type: Implementations of the Cloud
   Data Management Interface (CDMI) defined by the Storage Networking
   Industry Association (SNIA)

   Additional information:

      Magic number(s): n/a

      File extension(s): .cdmid

      Macintosh file type code(s): TEXT

   Person and email address to contact for further information: Arnold
   Jones arnold.jones@snia.org

   Intended usage: COMMON

   Restrictions on usage: none

   Author: SNIA Cloud Storage Initiative cloudtwg@snia.org

   Change controller: SNIA Cloud Storage Initiative cloudtwg@snia.org

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5.4.  Media Type application/cdmi-object

   Type name: application

   Subtype name: cdmi-object

   Required parameters: none

   Optional parameters: none

   Encoding considerations: Assumes that the representation is always
   UTF-8 as defined in [RFC3629] and 8bit as defined in [RFC4288].

   Security considerations: See Section 6 of draft-cdmi-mediatypes-07

   Interoperability considerations: none

   Published specification: draft-cdmi-mediatypes-07

   Applications that use this media type: Implementations of the Cloud
   Data Management Interface (CDMI) defined by the Storage Networking
   Industry Association (SNIA)

   Additional information:

      Magic number(s): n/a

      File extension(s): .cdmio

      Macintosh file type code(s): TEXT

   Person and email address to contact for further information: Arnold
   Jones arnold.jones@snia.org

   Intended usage: COMMON

   Restrictions on usage: none

   Author: SNIA Cloud Storage Initiative cloudtwg@snia.org

   Change controller: SNIA Cloud Storage Initiative cloudtwg@snia.org

5.5.  Media Type application/cdmi-queue

   Type name: application

   Subtype name: cdmi-queue

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   Required parameters: none

   Optional parameters: none

   Encoding considerations: Assumes that the representation is always
   UTF-8 as defined in [RFC3629] and 8bit as defined in [RFC4288].

   Security considerations: See Section 6 of draft-cdmi-mediatypes-07

   Interoperability considerations: none

   Published specification: draft-cdmi-mediatypes-07

   Applications that use this media type: Implementations of the Cloud
   Data Management Interface (CDMI) defined by the Storage Networking
   Industry Association (SNIA)

   Additional information:

      Magic number(s): n/a

      File extension(s): .cdmiq

      Macintosh file type code(s): TEXT

   Person and email address to contact for further information: Arnold
   Jones arnold.jones@snia.org

   Intended usage: COMMON

   Restrictions on usage: none

   Author: SNIA Cloud Storage Initiative cloudtwg@snia.org

   Change controller: SNIA Cloud Storage Initiative cloudtwg@snia.org

6.  Security Considerations

   This section was developed with RFC 3552 [RFC3552] as guide.  CDMI is
   an application interface and the relevant security considerations
   include confidentiality, integrity, access control and audit.
   Transport and end point security artifacts like DDoS are orthogonal
   and domains like non-repudiation are left to the application that
   employs this interface.

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6.1.  Confidentiality and Integrity

   The confidentiality and integrity of the CDMI exchanges are
   determined by the application that uses the interface.  CDMI does not
   contain any specific mechanisms, and relies on transport mechanisms
   such as TLS (see https [RFC2818]) for confidentiality and integrity
   of the messages across the network.

6.2.  Access Control

   The access control of the CDMI end point URLs are beyond this
   specification.  If required, applications should use appropriate URL
   authentication and authorization techniques, such as URI routers for
   different classes of users and restrict access based on URI origin.

   For fine-grained control of the CDMI objects, the CDMI specification
   [CDMI-1] contains the Access Control Lists (ACL) and Access Control
   Entries (ACE).  These are described fully in section 16.1 of the CDMI
   specification [CDMI-1].

6.3.  Audit

   The CDMI specification [CDMI-1] has defined a set of metadata fields,
   as explained in Section 16.3, to facilitate the incorporation of
   access and other audit markers.  The CDMI metadata system is
   extensible and the implementations can add more metadata as required
   by the security posture of the domain.

6.4.  JSON Security Considerations

   JSON related security considerations, described in RFC 4627 [RFC4627]
   apply.

6.5.  Executable/active content

   The CDMI interface does not include any directives for active
   content.

7.  Acknowledgements

   The authors wish to acknowledge the guidance and wisdom from Mark
   Carlson and Peter Saint-Andre, comments from Patrick Faltstrom, and
   the SNIA CDMI cloud twg for all the insightful discussions and ideas.

8.  References

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8.1.  Normative References

   [CDMI-1]   SNIA, "Cloud data management Interface Version 1.0", 2010,
              <http://www.snia.org/tech_activities/standards/
              curr_standards/cdmi>.

   [JSON-1]   json.org, "JavaScript Object Notation", 2006,
              <http://www.json.org/>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2616]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
              Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
              Transfer Protocol -- HTTP/1.1", RFC 2616, May 2000.

   [RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO
              10646", STD 63, RFC 3629, November 2003.

   [RFC3986]  Berners-Lee, T., "Uniform Resource Identifier (URI):
              Generic Syntax", RFC 3986, January 2005.

   [RFC4288]  Freed, N. and J. Klensin, "Media Type Specifications and
              Registration Procedures", BCP 13, RFC 4288, December 2005.

   [RFC4627]  Crockford, D., "The application/json Media Type for
              JavaScript Object Notation (JSON)", RFC 4627, July 2006.

8.2.  Informative References

   [RFC2818]  Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.

   [RFC3552]  Rescorla, E. and B. Korver, "Guidelines for Writing RFC
              Text on Security Considerations", BCP 72, RFC 3552,
              July 2003.

Authors' Addresses

   Krishna Sankar (editor)
   Cisco
   170 W.Tasman Drive
   San Jose, CA  95134
   USA

   Phone: (408) 853 8475
   Email: ksankar@cisco.com

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   Arnold Jones
   SNIA
   4410 ArrowsWest Drive
   Colorado Springs, CO  80907
   USA

   Phone: (407) 574 7273
   Email: arnold.jones@snia.org

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