Ubuntu Manpage: maDagAgent - DIET grid middleware agent

Provided by: diet-agent_2.8.0-1build2_amd64

NAME

       maDagAgent - DIET grid middleware agent

NAME

       maDagAgent - Main binary of the DIET Architecture for managing workflows

SYNOPSYS

          maDagAgent config_file [sched] [pfm] [IRD] ...

DESCRIPTION

       The maDagAgent is the daemon responsible for the management of workflows execution.

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

       sched  The policy used for scheduling workflows. This option can take the following values:

              • -basic (default):

              • -g_heft:

              • -g_aging_heft:

              • -fairness:

              • -srpt:

              • -fcfs: first come first serve

       pfm

              • -pfm_any (default)

              • -pfm_sameservices

       IRD

              • -IRD value

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.