Re: Parallel Computing Toolkit with ssh tunnels
- To: mathgroup at smc.vnet.net
- Subject: [mg87947] Re: Parallel Computing Toolkit with ssh tunnels
- From: Sascha Kratky <skratky at gmail.com>
- Date: Mon, 21 Apr 2008 03:24:09 -0400 (EDT)
- References: <email@example.com>
Hi Art, in order for SSH tunneling to work for your configuration, you have to use active MathLink connections that use standard input and output as MathLink transport, i.e., LaunchSlave["remotehost","ssh `1` math -mathlink", ConnectionType- >LinkLaunch] Also see http://documents.wolfram.com/applications/parallel/Configuration/Un= ix.html Regards, Sascha On Apr 14, 11:42 am, Art <grenan... at gmail.com> wrote: > I would like to create a poor man's parallel cluster using PCT to work > through ssh tunnels due circumvent firewall restrictions. > > I have 3 slave and 1 master linux machines with sshd running on port > 22 and no other ports open. Assume each machine is additionally behind > a physical firewall and has a local IP and the firewall port forwards > 22 to this machine. Authentication is set up without a password so > that the following works: > > me@master: ssh slave1 math > Mathematica 6.0 for Linux x86 (64-bit) > Copyright 1988-2008 Wolfram Research, Inc. > > In:= > > I haven't been able to get LaunchSlave to work with this setup with > various combinations of LinkName, LinkHost and for example, 'ssh -R > port1:127.0.0.1:port1 -R port2:127.0.0.1:port2' as replacement for > $RemoteCommand. > > It seems for each launch, the master listens on two new random ports > for each slave and instructs the slave to connect to these ports on a > specific IP. I think I have both an issue with the firewall and the > fact that meaningless local IPs are passed to the slaves rather than > the IP of the firewall. Even when I hand set the ports and open them > on the firewalls, I have problems. > > I am guessing the mathlink connection protocol is the same as > launching a remote kernel on a slave from the master, which I also > haven't been able to get to work with these firewalls and port > restrictions. I have been able to get it to work with all machines in > one local network and with no firewall restrictions. I have also been > able to use gdb to debug mathlink code using the similar two port > communication. > > I was wondering if anyone has gotten either PCT or remote kernel > launching through ssh tunnels to work. There are prior posts on this > forum and help on a wiki page:http://tinyurl.com/5ano5tbut I haven't > been able to get them to work either. I am using 6.0.2 on 64-bit > Ubuntu 7.10 with PCT 2.1. > > Thanks, > Art.