Hi Ismael, So I don’t actually know anything about setting up a Julia cluster specifically, but it sounds like you do indeed need to have an SSH server set up on each machine. That’s actually not very uncommon on linux boxes and it’s very possible there’s already one running by default.
One useful utility is `ssh-copy-id user@hostname` which will add your default public key ($HOME/.ssh/id_rsa.pub) to the authorized_keys list on the remote machine. Make sure to use the same remote machine user that you’ll be using later to log in from your Julia master node. The nice thing about ssh-copy-id is that it won’t add your key twice if you accidentally run it twice for the same remote machine. Hope that’s helpful. -s > On Sep 25, 2015, at 5:42 PM, Ismael VC <ismael.vc1...@gmail.com> wrote: > > Hello everyone! > > I am trying to set up a Julia cluster with 20 nodes, this is the very first > time I've tried something like this. I have looked around for examples, but > documentation is not very helpful for me: > > Julia can be started in parallel mode with either the -p or the --machinefile > options. -p n will launch an additional n worker processes, while > --machinefile file will launch a worker for each line in file file. The > machines defined in file must be accessible via a passwordless ssh login, > with Julia installed at the same location as the current host. Each machine > definition takes the form [count*][user@]host[:port] [bind_addr[:port]] . > user defaults to current user, port to the standard ssh port. count is the > number of workers to spawn on the node, and defaults to 1. The optional > bind-to bind_addr[:port] specifies the ip-address and port that other workers > should use to connect to this worker. > > This is what I think I have understood so far: > > Ok I list the machines on a machine file, that's easy, I have a file like > this: > > n user@555.555.555.555 > n user@555.555.555.556 > n user@555.555.555.555 > > > The machines defined in file must be accessible via a passwordless ssh login, > > This is the part that is difficult for me the most, it says that machines > must be accesible via paswordless ssh > > with Julia installed at the same location as the current host. > > I understand this as I need to install Julia en every node in the same > location, so I have 20 nodes, same software and hardware stacks. Does this > means that the nodes must be of the same operating system? the same bits > (32/64) only? > > Right now I have 20 CentOS 6.7 (64 bits) nodes with julia-0.3.11 installed > from the generic linux binaries (64bits), all of them installed at > /opt/julia-0.3.11/bin (added to the PATH and already exported in /etc/profile) > > Now the plan in my mind is to use my laptop (windows 7 64 bits, julia-0.3.11 > 64 bits) as master node and control the cluster with that, so according to > what I understand, I'll need to do (leaving password blank): > > ssh-keygen -t rsa > > > From my Windows laptop (I plan to install Arch Linux soon), in order to > create my ssh key and then: > > cat ~/.ssh/id_rsa.pub | ssh user@hostname 'cat >> .ssh/authorized_keys' > > > To every node? So I have to be running the ssh server at every one of them? > (I understand I'll need it at the master node) This is where I simply don't > understand anymore, I haven't seen any tutorial, or article, or something > like that, just that paragraph in the manual, I know there is > ClusterManagers.jl but that sounds even more complicated for me right now. > > I also want to help David Sanders to set up another cluster (once I got this > figured out) in his lab at Science Faculty, UNAM. I promise to enhance the > documentation around this topic once I understand this. > > What do you guys think, do I have it all wrong? > > If anyone can help me, I'll be very grateful, thank's in advance!
