9.3. Listing Hosts on the Command Line

Many PRRTE commands accept the --host CLI parameter. --host accepts a comma-delimited list of tokens of the form:

host[:slots]

The host token can be either:

  • A name that resolves to an IP address, or

  • An IP address

Note

The names and/or IP addresses of hosts are only used for identifying the target host on which to launch. They are not used for determining which network interfaces are used by applications (e.g., MPI or other network-based applications).

For network-based applications, consult their documentation for how to specify which network interfaces are used.

The optional integer :slots parameter tells PRRTE the maximum number of slots to use on that host (see this section on definition of the term slot for a description of what a “slot” is).

For example:

prterun --host node1:10,node2,node3:5 ...

--host selects from the hosts already available to the DVM — those a resource manager allocated, or those the DVM was started with. It does not add any. Naming a host that is not among them is an error, reported as:

At least one of the requested hosts is not included in the current
allocation.

   Missing requested host: node9

To bring a new host into a DVM that is already running, use --add-host or --add-hostfile instead.