The Server Configuration File

The server configuration file is used to customize the server. The default configuration file in $NETSOLVE_ROOT/server_config should be used as a template to create new configuration files. This configuration file is organized as follows. A line can start with a '#' in which case the line is ignored and can be used for comments. A line can also start with a keyword that is prefixed by a '@' typically followed by a single value or parameter. Let us review all of the possible keywords and how they can be used to precisely define a NetSolve server as it is done in the default configuration file.

• '@AGENT:<hostname>'[*] specifies the agent that the NetSolve server must contact to register into a NetSolve system. The agent is identified by the name of the host on which it is running and there can be only one such line in the configuration file. If the '*' is present, then the server will broadcast its existence to all NetSolve agents known to the one running on <hostname>. Otherwise, the server will only be known to the agent on <hostname>.

• '@PROC:<number>' specifies the number of processors (=1 for a single processor, =2 for a dual processor, =4 for a quad processor) that can be used by the server to perform simultaneous computations on the local hosts. There can only be one such line in the configuration file.

• '@MPIHOSTS <filename> <number>' specifies the path to the file that contains the list of machines that can be used by MPI, and the maximum number of processors that can be spawned by MPI.

• '@WORKLOADMAX:<max>' specifies the value of the workload beyond which the server refuses new requests (e.g. '@WORKLOADMAX:100'). A value of -1 means that the server accepts requests regardless of the workload.

• '@SCRATCH:<path>' specifies where the NetSolve server can put temporary directories and files. The default is /tmp/.

• '@CONDOR:<path>' specifies that the NetSolve server is using a Condor [condor1] [condor2] pool as a computing resource. The path to the Condor base directory must be provided. There can be only one such line in the configuration file.

• '@PROBLEMS:' marks the beginning of the list of problem description file (PDF) names that are enabled in the NetSolve server installation. Each of these problem description files contains interfaces to a number of problems/subroutines from a particular software library. If a particular problem description file is enabled in the server configuration file, then the problems/subroutines contained therein become available on that server. A number of PDFs have been written for a variety of software packages, but the default NetSolve installation only enables a small subset, as there is only a limited amount of software included with the NetSolve distribution. Details of description files are given in the section called Expanding the Server Capabilities in Chapter 13.

• '@RESTRICTIONS:' marks the beginning of the list of access restrictions that are applicable to the NetSolve server. The list consists of lines formatted as:

  <domain name> <number of pending requests allowed>

  The symbol '*' is used as a wildcard in the domain name. For instance, the line:

  *.edu 10

  means that only 10 requests from clients residing on a .edu machine can be serviced simultaneously. When the server receives a request from some machine, it determines which line in the list must be used to accept or reject the request by taking the most refined domain name. For instance, if the list of the restrictions is:

  *.edu 5 *.utk.edu 10

  then the server accepts at most 5 simultaneous requests coming from .edu machines that are not in the .utk.edu sub-domain, and at most 10 requests that come from machines in the .utk.edu sub-domain for a total of 15 possible simultaneous requests.