Axon is a computer cluster where a scheduler program is used to submit compute tasks, called jobs, to one or more nodes in the cluster. Jobs are submitted to the cluster via a login node (axon.rc.zi.columbia.edu) as show in the diagram below:
The login node (axon.rc.zi.columbia.edu) is for job preparation, not computation!
The login node has limited CPU and memory resources, and should only be used for the preparation of batch jobs or to start an interactive session on one of the nodes. Terminal sessions on axon.rc.zi.columbia.edu have limits enforced by the operating system- you may only use at most 1 GB of RAM and 6 hours worth of CPU time. Trying to use more resources will not work. This is to ensure that other researchers using the login node to submit jobs won't have their work disrupted.
Using SSH
Secure Shell (SSH) is the software used by Axon to provide you with a terminal interface. To connect to Axon using this software, you must have a command line interface on your personal computer such as Windows Terminal in Windows 10 or Terminal for Macs. Older versions of Windows may require a third-party program such as Putty or MobaXterm. Once you have a command line interface on your computer, you can use the following command to log in to Axon:
Connecting from inside the Columbia network or on the VPN
The Axon login node can be accessed when you are on the Columbia campus or using the VPN by using command below:
➤ ssh aa3301@axon.rc.zi.columbia.edu aa3301@axon.rc.zi.columbia.edu's password: Last login: Fri Dec 27 15:35:33 2019 from adm.rc.zi.columbia.edu [aa3301@axon ~]$
Connecting from outside the Columbia network
The Axon login node can be accessed anywhere outside the internal Columbia network by using command below:
> ssh -p 55 aa3301@axon-remote.rc.zi.columbia.edu aa3301@axon-remote.rc.zi.columbia.edu's password: Last login: Thu Apr 2 17:01:47 2020 from adm.rc.zi.columbia.edu Welcome to the Axon GPU Cluster! ...
You can make an ssh config file to abbreviate the above command. By creating a file named ~/.ssh/config (if it doesn't already exist) you can connect using a shorter name:
Host axon-remote HostName axon-remote.rc.zi.columbia.edu User aa3301 # change aa3301 above to your uni Port 55
Once you have ~/.ssh/config in place you can run the abbreviated ssh command shown below:
> ssh axon-remote aa3301@axon-remote.rc.zi.columbia.edu's password: Last login: Thu Apr 2 17:53:41 2020 from vpn-10-192-140-203.dyn.columbia.edu Welcome to the Axon GPU Cluster! ...
Connectivity from outside Columbia
While SSH is available from outside Columbia this method will only allow you to connect via ssh to the login node. All other ports on the login node and the compute nodes are only accessible from the Columbia campus. You can use ssh tunneling to connect to other ports, but this can be complicated and configuration is different depending on the usage.