On Thu, 2009-09-03 at 19:29 -0400, Graham, Richard L. wrote: > What happens if $sysconfdir/openmpi-priv-mca-params.conf is missing ?
If it is missing, everything works as today: any parameter declared in $sysconfdir/openmpi-mca-params.conf is considered as system-wide and can be overwritten as usual. > > Can the file name ( openmpi-priv-mca-params.conf ) also be configurable ? No, it isn't, presently, but this can be changed if needed. Regards, Nadia > > Rich > > > On 9/3/09 5:23 AM, "Nadia Derbey" <nadia.der...@bull.net> wrote: > > > > What: Define a way for the system administrator to prevent users from > overwriting the default system-wide MCA parameters settings. > > Why: Letting the user completely free of changing any MCA parameter > that has been defined on a system-wide basis may sometimes be > undesirable. > > Where: code can be found at > http://derb...@bitbucket.org/derbeyn/opal-ro-mca-params/ > > ------------------------------------------------------------------- > > Description: > > > Letting the user completely free of changing any parameter that has been > defined on a system-wide basis may sometimes be undesirable. For > example, on a node with multiple TCP interfaces, the system > administrator may for some reason want to restrict MPI applications to a > fixed subset of these TCP interfaces. > > Today, there is no way for the system administrator to prevent users > from overwriting the default system-wide settings: even if he has > excluded eth0 from the interfaces usable by an MPI application, he > cannot prevent any user from explicitly using that excluded interface. > > The purpose of this feature is to provide a new "system-wide-only" > property for the MCA parameters, specifying that their system-wide > value, if it has been defined, can never be overridden. This implies > changing the existing parameters setting rules. > > > Implementation: > > It should be noted that this feature is already described in > https://svn.open-mpi.org/trac/ompi/ticket/75 as follows: > "another MCA parameter file that has "privileged" MCA parameters. This > file is hard-coded in the code base (based on $prefix, likely > "$sysconfdir/openmpi-priv-mca-params.conf", or somesuch). Any parameters > set in this file will be treated specially and cannot be overridden." > > But we chose another way to implement this feature: the file > $sysconfdir/openmpi-mca-params.conf is kept with all the parameters > settings (even those that are considered as system-wide-only). > And the new file $sysconfdir/openmpi-priv-mca-params.conf is introduced > to contain only the list of the "privileged" parameters (not their value). > Doing it that way makes it easier to change the status of the MCA > parameters: moving them from privileged to non privileged is only a > matter of removing the new file, which preserves compatibility. > While with the solution proposed in the ticket, we have to merge both files. > > The configuration files are parsed in the following order: > 1. $sysconfdir/openmpi-mca-params.conf. > 2. $sysconfdir/openmpi-priv-mca-params.conf > 3. $HOME/.openmpi/mca-param.conf > > When openmpi-priv-mca-params.conf is parsed, any parameter listed in > that file is moved from the mca_base_param_file_values list to a new > parallel list (mca_base_priv_param_file_values). The parameter remains > "hidden" in that new list. > The lookup order has been changed: the new > mca_base_priv_param_file_values list is the very 1st one to be scanned: > this is how we ensure that the "privileged" parameters are never > overwritten once defined on a system-wide basis. > > Other external changes: > 1. The man page for mpirun(1) has been changed. > 2. The ompi_info(1) output has been changed to reflect the status of > these "privileged" parameters. The status field can now be one of > "read-only", "writable" or "privileged". > 3. A new option has been added to ompi_info(1): --privileged > it outputs only the list of parameters that have been defined as > system-wide-only. > > > TODO list: > . Make this feature configurable. > . Output a warning message as described in the ticket. > > > Possible extension to this functionality: > > This new functionality can be extended in the future in the following > way: allow the administrator to specify boundaries within which an MCA > parameter is allowed to be changed by a higher priority setting. This > means that the administrator should declare min and max values (or even > a set of discrete values) for any such parameter. Then, any higher > priority setting will be done only if the new value belongs to the > declared set. > In other word, each MCA parameter can be > 1. set to a given value in openmpi-mca-params.conf > 2. declared in openmpi-priv-mca-params.conf with its allowed boundaries > Then, if the user calls mpirun with that MCA parameter set in his > private mca-params.conf file, or in an AMCA file, or in an environment > variable, or on the command line, the new value will override the > system-wide value only if it is within the declared boundaries. > > This could be thought of as a future development. > > -- > Nadia Derbey <nadia.der...@bull.net> > > > > _______________________________________________ > devel mailing list > de...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/devel > > > _______________________________________________ > devel mailing list > de...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/devel > -- Nadia Derbey <nadia.der...@bull.net>
