Ubuntu Manpage: dietAgent - DIET grid middleware agent

Provided by: diet-agent_2.8.0-1build2_amd64

NAME

       dietAgent - DIET grid middleware agent

NAME

       dietAgent - Main binary of the DIET Architecture for running DIET Agents (master and local
       agents)

SYNOPSYS

          dietAgent [config file] ...

DESCRIPTION

       The DietAgent is the main binary of the DIET distribution.  It is used for both master and
       local agents of a DIET hierarchy.

DIET PLATFORM

A DIET platform is buildt upon Server Daemons (SeD). Requests are distributed amongst a
hierarchy of agents. The scheduler can rely on resources availability informations
collected from three different tools: NWS sensors which are placed on every node of the
hierarchy, from the application-centric performance prediction tool FAST which relies on
NWS informations or from CoRI Easy a module based on simple system calls and basic
performance tests.

The different components of a DIET architecture are the following:

Client A client is an application which uses DIET to solve computational problems.
Clients could be web pages, PSE scripts like Matlab or Scilab or native program.

Master Agent (MA)
A MA manages computation requests from clients. It chooses the best server
available to handle the request based on performance informations collected from
servers. Then, the reference of the chosen server is returned to the client.

Local Agent (LA)
A LA transmits requests between MAs and servers. LAs store a list of services
available in their subtree. For each service, LAs store a list of children (either
agents or servers) providing the former. Depending on the underlying network
topology, a hierarchy of LAs may exists between the MA and the appropriate servers,
one of LAs tasks is to do a partial scheduling on its subtree, effectively reducing
its MA workload.

Server Daemon (SeD)
A SeD encapsulate a computational resource. FOr instance, it can be locate on the
entry point of a parallel computer. SeD store a list of locally available data,
available computational solvers and performance-related information (available
memory amount or number or resources). During registration, SeD declare to its
parent agent (LA or MA) every computational problem it can solve. SeD can send
performance and hardware informations by using the CoRI module or performance
predictions for some kinds of problems by using the FAST module.

Master Agent DAG (MA DAG)
The Master Agent DAG (MADAG) provides DAG workflow scheduling. This agent serves as
the entry point to the Diet Hierarchy for a client that wants to submit a workflow.
The language supported by the MADAG is based on XML.

CORBA USAGE FOR DIET

       DIET relies on the CORBA naming service for service discovery  allowing  every  entity  to
       interconnect.  Reference  to  the  omniORB  naming  service  is  written  down  in a CORBA
       configuration file whose path  is  given  to  omniORB  through  the  environment  variable
       OMNIORB_CONFIG.

       The   lines   concerning   the  name server in the omniORB configuration file are built as
       follows:

          InitRef  =  NameService=corbaname::<hostname>:<port>

       The  name  server port is the port given as an argument to the -start option of omniNames.
       You  also  need  to update your LD LIBRARY PATH to  point to <install dir>/lib. So your LD
       LIBRARY PATH environment variable should now be :
          LD LIBRARY PATH=<omniORB home>/lib:<install dir>/lib.

          NB1:  In order to avoid name collision, every agent must be  assigned  a different name
          in the name server; since they don’t have any children, SeDs do not need names assigned
          to them and they don’t register with the name server.

          NB2:  Each  Diet  hierarchy can use a different name server,  or  multiple  hierarchies
          can  share  one  name  server  (assuming  all agents are assigned unique names).  In  a
          multi-MA environment, in order for multiple hierarchies to be able to cooperate  it  is
          necessary that they all share the same name server.

OPTIONS

       config_file
              Configuration file used by the agent to launch the DIET entity

DIET CONFIGURATION FILE

Every DIET entity requires a configuration file.

Please note that:

• comments start with ’#’ and finish at the end of the current line,

• meaningful lines have the format: keyword = value, following the format of configuration
files for omniORB 4,

• for options that accept 0 or 1, 0 means no and 1 means yes, and

• keywords are case sensitive.

Depending on the type of DIET element, different kinds of keyword could be found. Here
is a list of the possible keywords for a DIET Agent configuration file:

traceLevel
Integer value corresponding to the traceLevel for the DIET agent:

• 0: DIET do not print anything.

• 1: DIET prints only warnings and errors on the standard error output.

• 2: [default] DIET prints information on the main steps of a call.

• 5: DIET prints information on all internal steps too.

• 10: DIET prints all the communication structures too.

• >10: (traceLevel - 10) is given to the ORB to print CORBA messages too.

0 Diet do not print anything, – 1 Diet prints only warnings and errors on the
standard error output, – 2 [default] Diet prints information on the main steps of a
call, – 5 Diet prints information on all internal steps too, – 10 Diet prints all
the communication structures too, – > 10 (traceLevel - 10) is given to the ORB to
print CORBA messages too.

agentType
three possible values

• DIET MASTER AGENT (or MA) for a Master Agent

• DIET LOCAL AGENT (or LA) for a Local Agent

• DIET_MA_DAG for an MA DAG Agent

dietPort
Integer setting the listening port of the agent. If left empty, the ORB will get an
open port from the system (if default 2809 is busy).

dietHostName
String setting the listening interface of the agent. If left empty, the ORB will
use the system hostname (the first one if several are available).

name String identifying the element. Clients and children nodes (LAs and SeDs) must
point to the same CORBA Naming Service hosting the MA.

parentName
String identifying the parent agent.

[Remark: Only DIET Local Agents could use the parentName keyword]

fastUse
Boolean enabling/disabling FAST module. If set to 0, all LDAP and NWS parameters
are ignored, and all requests to FAST are disabled (when Diet is compiled with
FAST). This is useful while testing a DIET platform without having to deploy an
LDAP base nor an NWS platform.