Slots command in hostfile for mpirun not recognised

Question

I saw another question that seemed similar mpirun: token slots not supported but their solution did not work for me.

I get the error token slots not supported at this time when running the command mpirun -hostfile temp.txt hostname

where temp.txt is

hostname1 slots=2
hostname2 slots=2

I have the mpirun version 2021.5 Release Date: 20211102 (id: 9279b7d62).

It did not work to instead write

hostname1:2
hostname2:2

in that case the command runs but it instead does the number of physical processors that are available, which is default.

EDIT: I am adding the full output

[host RAMSES]$ mpirun -hostfile temp.txt hostname
[mpiexec@host] HYD_hostfile_process_tokens (../../../../../src/pm/i_hydra/libhydra/hostfile/hydra_hostfile.c:47): token slots not supported at this time
[mpiexec@host] HYD_hostfile_unique_parse (../../../../../src/pm/i_hydra/libhydra/hostfile/hydra_hostfile.c:232): unable to process token
[mpiexec@host] match_arg (../../../../../src/pm/i_hydra/libhydra/arg/hydra_arg.c:83): match handler returned error
[mpiexec@host] HYD_arg_parse_array (../../../../../src/pm/i_hydra/libhydra/arg/hydra_arg.c:128): argument matching returned error
[mpiexec@host] mpiexec_get_parameters (../../../../../src/pm/i_hydra/mpiexec/mpiexec_params.c:1359): error parsing input array
[mpiexec@host] main (../../../../../src/pm/i_hydra/mpiexec/mpiexec.c:1784): error parsing parameters

Answer 1

So I found that on my version of mpi I had to specify processor placement not in the hostfile, as most of the examples I found do, but rather in the machinefile.

So the new command and file look like:

mpirun -machinefile machine.txt hostname

machine.txt:

host1:2
host2:2