Internet DRAFT - draft-dreibholz-rserpool-applic-distcomp
draft-dreibholz-rserpool-applic-distcomp
Network Working Group T. Dreibholz
Internet-Draft SimulaMet
Intended status: Informational 26 September 2023
Expires: 29 March 2024
Applicability of Reliable Server Pooling for Real-Time Distributed
Computing
draft-dreibholz-rserpool-applic-distcomp-35
Abstract
This document describes the applicability of the Reliable Server
Pooling architecture to manage real-time distributed computing pools
and access the resources of such pools.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2
2. Distributed Computing using RSerPool . . . . . . . . . . . . 2
2.1. Requirements . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Architecture . . . . . . . . . . . . . . . . . . . . . . 3
2.3. Limitations . . . . . . . . . . . . . . . . . . . . . . . 4
3. Reference Implementation . . . . . . . . . . . . . . . . . . 4
4. Testbed Platform . . . . . . . . . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
Reliable Server Pooling defines protocols for providing highly
available services. The services are located in a pool of redundant
servers and if a server fails, another server will take over. The
only requirement put on these servers belonging to the pool is that
if state is maintained by the server, this state must be transferred
to the other server taking over.
The goal is to provide server-based redundancy. Transport and
network level redundancy are handled by the transport and network
layer protocols.
The application may choose to distribute its traffic over the servers
of the pool conforming to a certain policy.
1.1. Scope
The scope of this document is to explain the way of using Reliable
Server Pooling mechanisms to manage and access pools of Distributed
Computing resources.
1.2. Terminology
The terms are commonly identified in related work and can be found in
the Aggregate Server Access Protocol and Endpoint Handlespace
Redundancy Protocol Common Parameters document [6].
2. Distributed Computing using RSerPool
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2.1. Requirements
The application scenario for Distributed Computing is defined as
follows:
* Clients generate large computation jobs. Jobs have to be
processed by servers as soon as possible (real-time), i.e. unlike
concepts like SETI@home [21], it is not possible to let clients
fetch a job, process it later and may be some day upload the
result.
* Jobs may be partitionable, i.e. they can be split up to smaller
pieces which can be processed independently and the processing
results can be concatenated to the processing result of the
complete job. Jobs have to be processed by servers.
* Servers may be unreliable; i.e. user computers may be temporarily
added to the pool of computing resources and may be revoked when
they are used again by their owners. Furthermore, they may simply
disappear because of broken network connections (modems, etc.) or
power turned off.
* The processing power of servers in a pool of computing resources
may be very heterogeneous, i.e. a few supercomputers and many low-
end user PCs.
Maintaining a Distributed Computing pool for the scenario described
above arises the following requirements to the pool management:
* It must be possible to manage large server pools, e.g. up to some
hundreds or even thousands of servers.
* Due to heterogeneous processing resources within a pool, it must
be possible to use appropriate server selection procedures to
meaningfully utilize the available resources.
* It must be possible to dynamically add and remove servers.
* Servers may be unreliable, especially when the servers are
represented by user PCs. Failover mechanisms are required to
continue an interrupted computation session.
2.2. Architecture
All requirements for pool and session management of the Distributed
Computing scenario defined in the previous section can be fulfilled
by the Reliable Server Pooling architecture:
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* An efficient implementation of the handlespace management
structures allows pools to contain thousands of elements.
Handlespace management structures have been proposed, implemented
and analyzed in [15], [12].
* RSerPool allows to specify server selection rules by pool member
selection policies [8]. A set of adaptive and non-adaptive
policies is already defined. To fulfill the requirements of new
applications, it is also possible to define new policies.
Research has already been made on the subject of load distribution
efficiency of pool policies in Distributed Computing scenarios:
see [12], [14], [18], [19], [13] for details.
* Dynamic addition and removal of PEs is a feature of RSerPool [4].
* The control/data channel concept [3] of RSerPool realizes a
session layer. That is, RSerPool already handles the main task of
maintaining and monitoring connections between PUs and PEs; the
only task of the application layer to provide full failover
functionality is to realize an application-dependent failover
procedure. By the usage of client-based state synchronization
[14], [17] in the form of ASAP Cookies, a failover may be fully
transparent to the PU while only a state restoration is necessary
on the PE side. A demo application [22] using the RSerPool
session layer in a Distributed Computing application is described
in [16].
2.3. Limitations
Applying RSerPool for distributed computing applications, the duties
of the RSerPool architecture are still limited to the management of
pools and independent sessions only. It is in particular a non-goal
to provide functionalities like data synchronization among sessions,
user authentication, accounting or the support for more than one
administrative domain. Such functionalities are considered to be
application-specific and are therefore out of the scope of RSerPool.
3. Reference Implementation
The RSerPool reference implementation RSPLIB, including example
Distributed Computing applications, can be found at [22]. It
supports the functionalities defined by [3], [4], [5], [6] and [7] as
well as the options [9], [11] and [10]. An introduction to this
implementation is provided in [12].
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4. Testbed Platform
A large-scale and realistic Internet testbed platform with support
for the multi-homing feature of the underlying SCTP protocol is
NorNet. A description of NorNet is provided in [20], some further
information can be found on the project website [23].
5. Security Considerations
The protocols used in the Reliable Server Pooling architecture only
try to increase the availability of the servers in the network.
RSerPool protocols do not contain any protocol mechanisms which are
directly related to user message authentication, integrity and
confidentiality functions. For such features, it depends on the
IPSEC protocols or on Transport Layer Security (TLS) protocols for
its own security and on the architecture and/or security features of
its user protocols.
The RSerPool architecture allows the use of different transport
protocols for its application and control data exchange. These
transport protocols may have mechanisms for reducing the risk of
blind denial-of-service attacks and/or masquerade attacks. If such
measures are required by the applications, then it is advised to
check the SCTP (see [2]) applicability statement [1] for guidance on
this issue.
6. IANA Considerations
This document introduces no additional considerations for IANA.
7. References
7.1. Normative References
[1] Coene, L., "Stream Control Transmission Protocol
Applicability Statement", RFC 3257, DOI 10.17487/RFC3257,
April 2002, <https://www.rfc-editor.org/info/rfc3257>.
[2] Stewart, R., Ed., "Stream Control Transmission Protocol",
RFC 4960, DOI 10.17487/RFC4960, September 2007,
<https://www.rfc-editor.org/info/rfc4960>.
[3] Lei, P., Ong, L., Tuexen, M., and T. Dreibholz, "An
Overview of Reliable Server Pooling Protocols", RFC 5351,
DOI 10.17487/RFC5351, September 2008,
<https://www.rfc-editor.org/info/rfc5351>.
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[4] Stewart, R., Xie, Q., Stillman, M., and M. Tuexen,
"Aggregate Server Access Protocol (ASAP)", RFC 5352,
DOI 10.17487/RFC5352, September 2008,
<https://www.rfc-editor.org/info/rfc5352>.
[5] Xie, Q., Stewart, R., Stillman, M., Tuexen, M., and A.
Silverton, "Endpoint Handlespace Redundancy Protocol
(ENRP)", RFC 5353, DOI 10.17487/RFC5353, September 2008,
<https://www.rfc-editor.org/info/rfc5353>.
[6] Stewart, R., Xie, Q., Stillman, M., and M. Tuexen,
"Aggregate Server Access Protocol (ASAP) and Endpoint
Handlespace Redundancy Protocol (ENRP) Parameters",
RFC 5354, DOI 10.17487/RFC5354, September 2008,
<https://www.rfc-editor.org/info/rfc5354>.
[7] Stillman, M., Ed., Gopal, R., Guttman, E., Sengodan, S.,
and M. Holdrege, "Threats Introduced by Reliable Server
Pooling (RSerPool) and Requirements for Security in
Response to Threats", RFC 5355, DOI 10.17487/RFC5355,
September 2008, <https://www.rfc-editor.org/info/rfc5355>.
[8] Dreibholz, T. and M. Tuexen, "Reliable Server Pooling
Policies", RFC 5356, DOI 10.17487/RFC5356, September 2008,
<https://www.rfc-editor.org/info/rfc5356>.
[9] Dreibholz, T., "Handle Resolution Option for ASAP", Work
in Progress, Internet-Draft, draft-dreibholz-rserpool-
asap-hropt-29, 6 September 2021,
<https://www.ietf.org/archive/id/draft-dreibholz-rserpool-
asap-hropt-29.txt>.
[10] Dreibholz, T. and X. Zhou, "Definition of a Delay
Measurement Infrastructure and Delay-Sensitive Least-Used
Policy for Reliable Server Pooling", Work in Progress,
Internet-Draft, draft-dreibholz-rserpool-delay-28, 6
September 2021, <https://www.ietf.org/archive/id/draft-
dreibholz-rserpool-delay-28.txt>.
[11] Dreibholz, T. and X. Zhou, "Takeover Suggestion Flag for
the ENRP Handle Update Message", Work in Progress,
Internet-Draft, draft-dreibholz-rserpool-enrp-takeover-26,
6 September 2021, <https://www.ietf.org/archive/id/draft-
dreibholz-rserpool-enrp-takeover-26.txt>.
7.2. Informative References
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[12] Dreibholz, T., "Reliable Server Pooling – Evaluation,
Optimization and Extension of a Novel IETF Architecture",
7 March 2007, <https://duepublico.uni-duisburg-
essen.de/servlets/DerivateServlet/Derivate-16326/
Dre2006_final.pdf>.
[13] Dreibholz, T., Zhou, X., and E. P. Rathgeb, "A Performance
Evaluation of RSerPool Server Selection Policies in
Varying Heterogeneous Capacity Scenarios", Proceedings of
the 33rd IEEE EuroMirco Conference on Software Engineering
and Advanced Applications Pages 157-164,
ISBN 0-7695-2977-1, DOI 10.1109/EUROMICRO.2007.9, 29
August 2007, <https://www.wiwi.uni-
due.de/fileadmin/fileupload/I-
TDR/ReliableServer/Publications/EuroMicro2007.pdf>.
[14] Dreibholz, T. and E. P. Rathgeb, "Overview and Evaluation
of the Server Redundancy and Session Failover Mechanisms
in the Reliable Server Pooling Framework", International
Journal on Advances in Internet Technology (IJAIT) Number
1, Volume 2, Pages 1-14, ISSN 1942-2652, June 2009,
<https://www.wiwi.uni-due.de/fileadmin/fileupload/I-
TDR/ReliableServer/Publications/IJAIT2009.pdf>.
[15] Dreibholz, T. and E. P. Rathgeb, "An Evaluation of the
Pool Maintenance Overhead in Reliable Server Pooling
Systems", SERSC International Journal on Hybrid
Information Technology (IJHIT) Number 2, Volume 1, Pages
17-32, ISSN 1738-9968, April 2008, <https://www.wiwi.uni-
due.de/fileadmin/fileupload/I-
TDR/ReliableServer/Publications/IJHIT2008.pdf>.
[16] Dreibholz, T. and E. P. Rathgeb, "An Application
Demonstration of the Reliable Server Pooling
Framework", Proceedings of the 24th IEEE INFOCOM, 16
March 2005, <https://www.wiwi.uni-
due.de/fileadmin/fileupload/I-
TDR/ReliableServer/Publications/Infocom2005.pdf>.
[17] Dreibholz, T., "An Efficient Approach for State Sharing in
Server Pools", Proceedings of the 27th IEEE Local Computer
Networks Conference (LCN) Pages 348-349,
ISBN 0-7695-1591-6, DOI 10.1109/LCN.2002.1181806, 8
November 2002, <https://www.wiwi.uni-
due.de/fileadmin/fileupload/I-
TDR/ReliableServer/Publications/StateSharing-Paper-
ShortVersion.pdf>.
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[18] Dreibholz, T. and E. P. Rathgeb, "On the Performance of
Reliable Server Pooling Systems", Proceedings of the IEEE
Conference on Local Computer Networks (LCN) 30th
Anniversary Pages 200-208, ISBN 0-7695-2421-4,
DOI 10.1109/LCN.2005.98, 16 November 2005,
<https://www.wiwi.uni-due.de/fileadmin/fileupload/I-
TDR/ReliableServer/Publications/LCN2005.pdf>.
[19] Dreibholz, T. and E. P. Rathgeb, "The Performance of
Reliable Server Pooling Systems in Different Server
Capacity Scenarios", Proceedings of the IEEE
TENCON ISBN 0-7803-9312-0, DOI 10.1109/TENCON.2005.300939,
22 November 2005, <https://www.wiwi.uni-
due.de/fileadmin/fileupload/I-
TDR/ReliableServer/Publications/Tencon2005.pdf>.
[20] Dreibholz, T. and E. G. Gran, "Design and Implementation
of the NorNet Core Research Testbed for Multi-Homed
Systems", Proceedings of the 3nd International Workshop on
Protocols and Applications with Multi-Homing
Support (PAMS) Pages 1094-1100, ISBN 978-0-7695-4952-1,
DOI 10.1109/WAINA.2013.71, 27 March 2013,
<https://www.simula.no/file/
threfereedinproceedingsreference2012-12-207643198512pdf/
download>.
[21] SETI Project, "SETI@home: Search for Extraterrestrial
Intelligence at home", 2022,
<https://setiathome.ssl.berkeley.edu/>.
[22] Dreibholz, T., "Thomas Dreibholz's RSerPool Page", 2022,
<https://www.nntb.no/~dreibh/rserpool/>.
[23] Dreibholz, T., "NorNet – A Real-World, Large-Scale Multi-
Homing Testbed", 2022, <https://www.nntb.no/>.
Author's Address
Thomas Dreibholz
Simula Metropolitan Centre for Digital Engineering
Pilestredet 52
0167 Oslo
Norway
Email: dreibh@simula.no
URI: https://www.simula.no/people/dreibh
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