jGMA: A Reference Implementation of the Grid Monitoring Architecture Mat Grove Distributed Systems Group University of Portsmouth

2 Outline  Introduction and Motivation.  The Grid Monitoring Architecture (GMA).  The jGMA Implementation.  Summary and future work.  jGMA Demo.

3 And and the the a  GridRM is:  A generic resource monitoring system – basically a framework for gathering data from heterogeneous data sources,  A scalable means of monitoring resources distributed over the Grid,  Written in Java, using commons standards:  Such as SQL, JDBC, Java Servlets, GLUE.  GridRM is made up of local and global layers; the latter basically is the means of transporting GridRM data between grid sites.  GridRM needed a “standards-based” transport layer to bind together these its sites at the global layer.  A GMA-based transport appeared to be the best candidate. Introduction

4 GridRM (gridrm.org)

5 And and the the a The Grid Monitoring Architecture  The GGF’s GMA document is their suggested “informational” means for monitoring within the Grid:  Note Informational documents are used to inform the community about a useful idea or set of ideas.  The GMA document (2001) recommends:  A publish, subscribe and bind architecture,  An implementation that is:  Secure and scalable,  Has a low-latency and capable of high data rates,  Imposes minimal impact on the infrastructure.  GMA compliancy means implementing approximately 20 features.

6 GMA Components Registry Producer Consumer Events Publish/Search Bind

7 And and the the a Some GMA Implementations  In the first instance we wanted to take up an off-the-shelf GMA package, several out there.  Embedded (part of a larger s/w package):  e.g. AutoPilot and Globus MDS:  MDS can be extracted into a standalone infrastructure with a little effort.  Standalone:  pyGMA (Berkeley National Lab), and R-GMA (DataGrid/LCG).  None of these implementations met GridRM’s requirements:  Easy to integrate within GridRM (Java-based),  Simple installation with minimal dependencies,  No need to “fork” parent software tree,  GMA compliance.

8 jGMA Components  jGMA has the following components:  A registry,  A producer and consumer (shared code-base),  A PC Servlet (provides WAN access between producers and consumers).  jGMA features:  Written in Java, so takes advantage of usual features and libraries,  Small API (<20 calls),  Released as single “jar” of currently 28Kbytes.  Limited dependencies:  Tomcat and Java.

9 jGMA Implementation

10 jGMA Optimisations  The jGMA Implementation:  Non-blocking communications:  Local communications use Java sockets:  RMI,  Serialising objects,  Packed binary arrays,  WAN communication use HTTP:  HTTP POST,  Encapsulating binary data.  Performance Tests:  Latency (Over Ethernet 1.5ms, Localhost 0.8ms),  Throughput (~1200 messages per second),  Scalability (tested stability under heavy loads).

11 Consumer pseudo code. Consumer(){ Connector=new JgmaConnector(“holly.dsg.port.ac.uk”); Connector.register(“pinger”); } Registered(){ Connector.registryQuery(“select * from producers”); } RegistryEvent(result){ for each result as producer{ Connector.sendMessage(producer, “ping”); }

12 Producer pseudo code. Producer(){ Connector=new JgmaCOnnector(“holly.dsg.port.ac.uk”); Connector.register(“ponger”); } MessageEvent(message){ Connector.replyMessage(message, “pong”); }

13  LAN address:  WAN address: Example jGMA Addressing. socket:// :56099/producer/cam http ://dsg.port.ac.uk:8080/jGMA/PC?

14 Summary  Summary:  jGMA is a reference implementation of GMA written in Java,  jGMA is a easy to use, simple, scalable and a robust system,  Our early tests show that jGMA has good performance and scalability.  Some issues need dealing with:  Throttling.

15 Future Work  Future developments:  Implement a persistent registry:  File (ASCII text),  R-DBMS (i.e. MySQL),  XML (i.e. Xindice).  Completing the leasing infrastructure,  Virtual Registry,  Monitoring via PC Servlet,  Hooks for debugging,  Being deployed in GridRM,  Look at working with other GMA developers to get an agreement on a standardised wire API.

16 Demo

17 Download  Available: jGMA beta  New version for October: 

18 Links  Project Web page:   The DSG Web page:   GridRM:   Related links:  GGF:  R-GMA:

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