I personally have no objection, but I would ask then that the wiki be modified to cover this case. All I require is that someone define the syntax to be used to indicate "this is a node I do -not- want used", or alternatively a flag that indicates "all nodes below are -not- to be used".
Implementation isn't too hard once I have that... On 3/3/08 9:44 AM, "Edgar Gabriel" <gabr...@cs.uh.edu> wrote: > Ralph, > > could this mechanism be used also to exclude a node, indicating to never > run a job there? Here is the problem that I face quite often: students > working on the homework forget to allocate a partition on the cluster, > and just type mpirun. Because of that, all jobs end up running on the > front-end node. > > If we would have now the ability to specify in a default hostfile, to > never run a job on a specified node (e.g. the front end node), users > would get an error message when trying to do that. I am aware that > that's a little ugly... > > THanks > edgar > > Ralph Castain wrote: >> I forget all the formatting we are supposed to use, so I hope you'll all >> just bear with me. >> >> George brought up the fact that we used to have an MCA param to specify a >> hostfile to use for a job. The hostfile behavior described on the wiki, >> however, doesn't provide for that option. It associates a hostfile with a >> specific app_context, and provides a detailed hierarchical layout of how >> mpirun is to interpret that information. >> >> What I propose to do is add an MCA param called "OMPI_MCA_default_hostfile" >> to replace the deprecated capability. If found, the system's behavior will >> be: >> >> 1. in a managed environment, the default hostfile will be used to filter the >> discovered nodes to define the available node pool. Any hostfile and/or dash >> host options provided to an app_context will be used to further filter the >> node pool to define the specific nodes for use by that app_context. Thus, >> nodes in the hostfile and dash host options given to an app_context -must- >> also be in the default hostfile in order to be available for use by that >> app_context - any nodes in the app_context options that are not in the >> default hostfile will be ignored. >> >> 2. in an unmanaged environment, the default hostfile will be used to define >> the available node pool. Any hostfile and/or dash host options provided to >> an app_context will be used to filter the node pool to define the specific >> nodes for use by that app_context, subject to the previous caveat. However, >> add-hostfile and add-host options will add nodes to the node pool for use >> -only- by the associated app_context. >> >> >> I believe this proposed behavior is consistent with that described on the >> wiki, and would be relatively easy to implement. If nobody objects, I will >> do so by end-of-day 3/6. >> >> Comments, suggestions, objections - all are welcome! >> Ralph >> >> >> _______________________________________________ >> devel mailing list >> de...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/devel
