If the Docker containers have different IP addresses, Open MPI will think that they are different "nodes" (or "hosts" or "servers" or whatever your favorite word is), and therefore will assume that they processes in these different containers are unable to share memory.
Meaning: no work has been done to make Open MPI understand Docker shared memory (i.e., you're the first person to ask about it). Pull requests would always be appreciated. ;-) > On Mar 24, 2017, at 5:47 AM, Jordi Guitart <jordi.guit...@bsc.es> wrote: > > Hello John, > > Yes, in fact, I'm comparing Docker with Singularity regarding the execution > of MPI applications :-) > > I'd like to make the comparison fairer by allowing Docker containers to share > memory. > > Thanks > > On 24/03/2017 10:00, John Hearns via users wrote: >> Jordi, >> this is not an answer to your question. However have you looked at >> Singularity: >> http://singularity.lbl.gov/ >> >> >> >> On 24 March 2017 at 08:54, Jordi Guitart <jordi.guit...@bsc.es> wrote: >> Hello, >> >> Docker allows several containers running in the same host to share the same >> IPC namespace, thus they can share memory (see example here: >> https://github.com/docker/docker/pull/8211#issuecomment-56873448). I assume >> this could be used by OpenMPI to communicate MPI processes running in >> different Docker containers in the same host by using shared memory (sm or >> vader). However, I cannot make it work. I tried to force mpirun to use >> shared memory (--mca btl self, sm) but it complains that MPI processes >> running in other Docker containers are not reachable. It seems like OpenMPI >> cannot recognize that shared memory is available between containers. Has >> anybody any hint about how this could be worked out? >> >> Thanks >> >> >> http://bsc.es/disclaimer >> _______________________________________________ >> users mailing list >> users@lists.open-mpi.org >> https://rfd.newmexicoconsortium.org/mailman/listinfo/users >> >> >> >> _______________________________________________ >> users mailing list >> >> users@lists.open-mpi.org >> https://rfd.newmexicoconsortium.org/mailman/listinfo/users > > > > WARNING / LEGAL TEXT: This message is intended only for the use of the > individual or entity to which it is addressed and may contain information > which is privileged, confidential, proprietary, or exempt from disclosure > under applicable law. If you are not the intended recipient or the person > responsible for delivering the message to the intended recipient, you are > strictly prohibited from disclosing, distributing, copying, or in any way > using this message. If you have received this communication in error, please > notify the sender and destroy and delete any copies you may have received. > > http://www.bsc.es/disclaimer > _______________________________________________ > users mailing list > users@lists.open-mpi.org > https://rfd.newmexicoconsortium.org/mailman/listinfo/users -- Jeff Squyres jsquy...@cisco.com _______________________________________________ users mailing list users@lists.open-mpi.org https://rfd.newmexicoconsortium.org/mailman/listinfo/users
