Bogdan Costescu <bogdan.coste...@iwr.uni-heidelberg.de>: >I beg to disagree. In a setup like the one mentioned, after orted is >started via an IPv4-only rsh/ssh, OpenMPI applications could use IPv6 >without problems, just like they could use f.e. GM if Myrinet cards >would be present. I see this very much like your past experience with
Ok, I slowly get the point... ;-) I see two possibilities concerning machinefile contents and how this affects both rsh/ssh and OpenMPI. 1. Put IPv[46] addresses into the machinefile. Since they are protocol-specific, both rsh/ssh uses them just the way they are. OpenMPI performs interface discovery, possibly getting more addresses. The use of these addresses is controlled via runtime configuration. 2. Put hostnames into the machinefile. Both rsh/ssh and OpenMPI perform their own resolver lookup. When the resolver library gives both addresses (IPv4 and IPv6), which one to used is handled via OpenMPI runtime configuration. What rsh/ssh do depends on them. Note that you can specify an IP protocol selection at least with ssh (-4/-6 cmdline switches). Your setup (IPv6 addresses given by the resolver, but no IPv6-aware ssh) could be handled in both ways: either by putting numeric IPv4-addresses into the machinefile, or by specifying 'ssh -4'. Is this a solution? Christian -- Dipl.-Inf. Christian Kauhaus <>< Lehrstuhl fuer Rechnerarchitektur und -kommunikation Institut fuer Informatik * Ernst-Abbe-Platz 1-2 * D-07743 Jena Tel: +49 3641 9 46376 * Fax: +49 3641 9 46372 * Raum 3217
