Hi, you provided the following information about the warning "too many ssh connections":
The particular warning is issued by hydra, MPICH's process manager. Following excerpt is the comment in that source code:
/* ssh has many types of security controls that do not allow a
* user to ssh to the same node multiple times very
* quickly. If this happens, the ssh daemons disables ssh
* connections causing the job to fail. This is basically a
* hack to slow down ssh connections to the same node. We
* check for offset == 0 before applying this hack, so we only
* slow down the cases where ssh is being used, and not the
* cases where we fall back to fork. */
Is this just during an initial ssh connection attempt? I'm trying to figure out where my code is triggering this warning. Could it be from
1. MPI_Intercomm_create
2. MPI_Comm_spawn
3. others?
I'm calling mpiexec with the "-launcher ssh" option, MPICH 4.0.1.
Thanks,
Kurt
