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ORTE_HOSTS(7) | Open MPI | ORTE_HOSTS(7) |
NAME¶
ORTE_HOSTS - OpenRTE Hostfile and HOST Behavior: Overview of OpenRTE's support for user-supplied hostfiles and comma-delimited lists of hostsDESCRIPTION¶
OpenRTE supports several levels of user-specified host lists based on an established precedence order. Users can specify a default hostfile that contains a list of nodes available to all app_contexts given on the command line. Only one default hostfile can be provided for any job. In addition, users can specify a hostfile that contains a list of nodes to be used for a specific app_context, or can provide a comma-delimited list of nodes to be used for that app_context via the -host command line option.default hostfile host hostfile Result ---------- ------ ---------- ----------------------------------------- unset unset unset Job is co-located with mpirun unset set unset Host defines resource list for the job unset unset set Hostfile defines resource list for the job unset set set Hostfile defines resource list for the job, then host filters the list to define the final set of nodes available to each application within the job set unset unset Default hostfile defines resource list for the job set set unset Default hostfile defines resource list for the job, then host filters the list to define the final set of nodes available to each application within the job set set set Default hostfile defines resource list for the job, then hostfile filters the list, and then host filters the list to define the final set of nodes available to each application within the job
RELATIVE INDEXING¶
Once an initial allocation has been specified (whether by an RM, default hostfile, or hostfile), subsequent hostfile and -host specifications can be made using relative indexing. This allows a user to stipulate which hosts are to be used for a given app_context without specifying the particular host name, but rather its relative position in the allocation.- +n<#>
- A relative index into the allocation referencing the <#> node. OpenRTE will substitute the <#> node in the allocation
- +e[:<#>]
- A request for <#> empty nodes - i.e., OpenRTE is to
substitute this reference with <#> nodes that have not yet been used
by any other app_context. If the ":<#>" is not provided,
OpenRTE will substitute the reference with all empty nodes. Note that
OpenRTE does track the empty nodes that have been assigned in this manner,
so multiple uses of this option will result in assignment of unique nodes
up to the limit of the available empty nodes. Requests for more empty
nodes than are available will generate an error.
dummy1 slots=4 dummy2 slots=4 dummy3 slots=4 dummy4 slots=4 dummy5 slots=4
+n2 slots=2 +e:1 dummy4 slots=1 +n2 +e
mpirun --default-hostfile dummyhosts -hostfile mylayout -mca rmaps seq ./my_app
Note that the sequential mapper ignores the number of slots arguments as it only maps one rank at a time to each node in the list.rank0 being mapped to dummy3rank1 to dummy1 as the first empty noderank2 to dummy4rank3 to dummy3rank4 to dummy2 and rank5 to dummy5 as the last remaining unused nodes
ranks 0 and 1 being mapped to dummy3 since two slots were specifiedranks 2-5 on dummy1 as the first empty node, which has four slotsrank6 on dummy4 since the hostfile specifies only a single slot from that node is to be usedranks 7 and 8 on dummy3 since only two slots remain availableranks 9-12 on dummy2 since it is the next available empty node and has four slotsranks 13-16 on dummy5 since it is the last remaining unused node and has four slots
SEE ALSO¶
orterun(1)
February 10, 2012 | 1.4.5 |