Change Propagation in a heterogeneous Application Landscape

© Fraunhofer IAO, IAT Universität Stuttgart

Message based propagation of changes in VO membership in a Grid environment

Change Propagation in a heterogeneous Application Landscape

Cracow Grid Workshop 2009Oliver StraussFraunhofer IAO, Stuttgart, Germany

Cracow, October 13th 2009


Slide 2

Outline

Background and motivation

Overview and architecture

Example

Conclusion


Slide 3

GNS Systems

(Provider of numerical services)

Background: PartnerGrid

Goal: Usage of Grid in a commercial environment

Scenario: Portal based collaboration between a provider of crash simulations and its customers

RCE

GNS-Customer

Grid

G I A

RCEEngineer

RCEEngineer

...

Consultant

Animator

Generator

INDEED

Portal


Slide 4

Problem: Keep the Grid in sync with the VO

Scenario: A new user enters the VO Accounts have to be created Roles in different systems

have to be assigned Access rights have to be set

Shell scripts work well for most tasks

PartnerGridVOMRS

VO-Representative

(potential)VO-Members

approves register

Data manageme

ntaccounts +

rights

WebDAVaccess rigths

Grid resources

affects

D-Gridmap

Web portal accounts,

roles, rights

Whitelist

What if we want to have a whitelist of grid users or other sources of change that affect the Grid configuration?


Slide 5

Problem: Keep the Grid in sync with the VO

Scenario: A new user enters the VO Accounts have to be created Roles in different systems

have to be assigned Access rights have to be set

Shell scripts work well for most tasks

PartnerGridVOMRS

VO-Representative

(potential)VO-Members

approves register

Data manageme

ntaccounts +

rights

WebDAVaccess rigths

Grid resources affects

D-Gridmap

Web portal accounts,

roles, rights

Whitelist

What if we want to have a whitelist of grid users or other sources of change that affect the Grid configuration?

Idea: Why not take an event based approach and use messaging to propagate changes?

Changemanager


Slide 6

Architecture: Message based change propagation

Source of changegrid-mapfile

Change adapter

Target of change Liferay Portal

Change adapter

Target of changeWebDAV

Change adapter

Message queueserver

Change Manager(Rule engine)

Incoming queue:

Changes

Dataprocessing

andenhancement

Messagerouting

Outgoing queue:Liferay

Outgoingqueue:

WebDAV

1 2

3

45

7

Rules

Rules

7Trigger

0 6

gridmapDN

UsernameVO Roles

gridmapDN

UsernameVO Roles

ApacheUsername

Generated PW

LiferayDN

UsernameOrganisationPortal Roles

email

Add. queues:LoggingErrorsMailetc…

Tools

…

ack

ack


Slide 7

Adapters

Adapters have to be provided for each system

Inside the target system (e.g. as a Liferay Portlet)

Acting from the outside (e.g. via an API, WebServices, shell scripts)

Adapter have very limited responsibilities

Source adapters

Detect and submit changes to a message queue

Target adapters

Receive from a message queue and execute changes

Acknowledge success or report error

Optionally submit logging information

Adapters can be implemented in any language for which a Stomp client is available (e.g. Java, Ruby, Python, …)


Slide 8

Change Manager

The Change Manager

receives requests on the “Incoming“ queue

feeds the change messages to the rule engine

Data normalization and enhancement

Lookup in external directories (e.g. LDAP)

Blacklists and whitelists

Send processed change request to output queue of the target system

Prototype implemented based on

Stompserver (Ruby) message queue

Rule engine (Rools)


Slide 9

Example rules

# Receive original message and insert a GridmapChange object in the rule enginerule 'receiveGridmapChange' do parameter Message, :source, :body, :change_type condition { msg.source == "gridmap" } consequence { assert GridmapChange.new( msg.body, msg.source, msg.change_type ) }end

# On GridmapChange objects with organisation “IAO” change organization to# “Fraunhofer IAO”rule 'normalizeO' do parameter GridmapChange, :o condition { change.o == "IAO" } consequence { change.o = "Fraunhofer IAO" }end

# Send every GridmapChange object with change_type “add” to the targetrule 'addLiferayUser' do parameter GridmapChange, :change_type condition { change.change_type == "add" } consequence { send_add_liferay_user( change, “[email protected]” ) }end


Slide 10

Discussion and future work

Advantages

Decoupling of change detection, data manipulation and change execution facilitates reuse

Modular system with explicit rule based logic provides good flexibility

Centralized logging (audit trail)

Easier maintenance and better extensibility expected

Easy integration with other tools like e.g. LDAP

Possible disadvantages

Introduction of a single point of failure

More complexity, one more server, more things that can go wrong

Security is crucial, since much harm can be done by injecting malicious messages

Future work

Further test practicability in the PartnerGrid scenario

Improve security (transfer via HTTPS, encryption and signing of messages)


Slide 11

Contact

Fraunhofer-Institute for

Industrial Engineering (IAO)

Oliver Strauss

Research Assistant / Software Technology

Mail: [email protected]

Web: www.swm.iao.fraunhofer.de

Documents

Change Propagation in a heterogeneous Application Landscape