Hi Jeff,
Thanks a lot for your answer, It really makes sense. Do you know where can I find more information about the *process launch on remote nodes* of MPI and all the alternatives I have? Thanks and regards. ________________________________ From: users <users-boun...@lists.open-mpi.org> on behalf of Jeff Squyres (jsquyres) via users <users@lists.open-mpi.org> Sent: Wednesday, December 19, 2018 7:18:23 PM To: Open MPI User's List Cc: Jeff Squyres (jsquyres) Subject: Re: [OMPI users] It's possible to get mpi working without ssh? On Dec 19, 2018, at 11:42 AM, Daniel Edreira <dedre...@plainconcepts.com> wrote: > > Does anyone know if there's a possibility to configure a cluster of nodes to > communicate with each other with mpirun without using SSH? > > Someone is asking me about making a cluster with Infiniband that does not use > SSH to communicate using OpenMPI. I'm not entirely clear what you're asking. You mention both "ssh" and "communication" -- they're kinda different things. Communication: Over an InfiniBand cluster, we'd recommend that you use the UCX library for Open MPI to communicate over IB. I.e., when your MPI application invokes API calls like MPI_Send() and MPI_Recv(), they'll use the UCX library underneath and utilize native IB-style communication (i.e., they're not using the POSIX sockets API -- they're using the native UCX/verbs APIs for RDMA OS bypass and offload, ...etc.). Ssh: ssh is not used for *communication*, per se; it's used for *starting Linux processes on remote nodes. Open MPI can use SSH to start processes on remote nodes, but it can also use other mechanisms (e.g., if you have a resource manager such as SLURM, Open MPI can use SLURM's native remote process launching mechanism instead of SSH). These two things are orthogonal to each other: you can use whatever *communication* mechanism you want for MPI APIs (e.g., the POSIX sockets API or the UCX library or ...several other APIs...), and use whatever *process launch* mechanism you want (e.g., SSH or SLURM's native remote process launch or ...several others...). Put simply: the choice of MPI communication layer does not imply anything about the remote process launch mechanism, and vice versa. Make sense? -- Jeff Squyres jsquy...@cisco.com _______________________________________________ users mailing list users@lists.open-mpi.org https://lists.open-mpi.org/mailman/listinfo/users
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