Parallel Computing Toolkit with ssh tunnels
- To: mathgroup at smc.vnet.net
- Subject: [mg87599] Parallel Computing Toolkit with ssh tunnels
- From: Art <grenander at gmail.com>
- Date: Mon, 14 Apr 2008 05:42:54 -0400 (EDT)
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[1]:= 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/5ano5t but 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.