<no title> — PMIx Reference Run Time Environment 3.0.2a1 documentation

PRRTE supports several levels of user-specified hostfiles based on an established precedence order. Users can specify a hostfile that contains a list of nodes to be used for the job, or can provide a comma-delimited list of nodes to be used for that job via the `--host` command line option.

The precedence order applied to these various options depends to some extent on the local environment. The following table illustrates how host and hostfile directives work together to define the set of hosts upon which a DVM will execute the job in the absence of a resource manager (RM):

host | hostfile | Result
--- | --- | ---
unset | unset | The DVM will utilize all its available resources when mapping the job.
set | unset | Host option defines resource list for the job
unset | set | Hostfile defines resource list for the job
set | set | Hostfile defines resource list for the job, then host filters the list to define the final set of nodes to be used for the job