Request Management System (Work in Progress)

.._request-management-system

Request Management System

The DIRAC Request Management System (RMS) provides functionality for asynchronous execution of certain operations, basically delayed request to any DIRAC service (diset operations) and data management operations (transfer, removal or register). The default configuration of the system includes a central RequestManager Service plus a number of Agents executing the different requests. Additionally, and since this system is used a failover mechanism for many operations, additional alternate RequestManager servers can be setup, that will take to forward the requests to the central server for execution in case this server is down temporarily.

Installing the Central Request Manager

A number of components need to be installed in the server hosting the central Request Manager functionality. They can be installed on a running DIRAC server using the following request.cfg file as example:

LocalInstallation
{
  Systems = RequestManagement
  Databases = RequestDB
  Services = RequestManagement/RequestManager
  Agents = RequestManagement/DISETForwardingAgent, RequestManagement/RequestCleaningAgent
}

Executing "dirac-setup-site request.cfg" will install and configure the central RequestManager service, using File as backend for the requests. To use MySQL as backend, you should edit the file /opt/dirac/etc/RequestManagement_RequestManager.cfg and overwrite the default there:

Systems
{
  RequestManagement
  {
    [Instance]
    {
      Services
      {
        RequestManager
        {
          Backend = mysql
        }
      }
    }
  }
}

At the same time, two Agents will be setup. One to forward DISET queries to other DIRAC components and another to cleanup old requests in the system.