Hi, Am 12.03.2014 um 07:37 schrieb Victor:
> I am using openmpi 1.7.4 on Ubuntu 12.04 x64 and I have a very odd problem. > > I have 4 nodes, all of which are defined in the hostfile and in /etc/hosts. > > I can log into each node using ssh and certificate method from the shell that > is running the mpi job, by sing their name as defined in /etc/hosts. > > I can run an mpi job if I include only 3 nodes in the hostfile, for example: > > Node1 slots=8 max-slots=8 > Node2 slots=8 max-slots=8 > Node3 slots=8 max-slots=8 You are using an uppercase name here by intention - this is the one the host returns by `hostname`? Although it is allowed and should be mangled to lowercase resp. ignored for hostname resolution, I found that not all programs are doing it. Best is to use only lowercase characters is my experience. The same version of your Ubuntu Linux is installed on all machines? -- Reuti > But if I add a fourth node into the hostfile eg: > > Node1 slots=8 max-slots=8 > Node2 slots=8 max-slots=8 > Node3 slots=8 max-slots=8 > Node4 slots=8 max-slots=8 > > I get this error after attempting mpirun -np 32 --hostfile hostfile a.out: > > ssh: Could not resolve hostname Node4: Name or service not known. > > But, I can log into Node4 using ssh from the same shell by using ssh Node4. > > Also if I mix up the hostfile like this for example and place Node1 to the > last spot: > > Node4 slots=8 max-slots=8 > Node2 slots=8 max-slots=8 > Node3 slots=8 max-slots=8 > Node1 slots=8 max-slots=8 > > The error becomes > > ssh: Could not resolve hostname Node1: Name or service not known. > > If I then go back to the three node hostfile like this: > > Node1 slots=8 max-slots=8 > Node4 slots=8 max-slots=8 > Node2 slots=8 max-slots=8 > > There is no error with three nodes even though both Node1 and Node4 "cannot > be found" if they are present in a 4 node hostfile in the last spot. The last > slot seems to be bugged. > > What is going on? How do I fix this? > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
