Axon is a Beowulf style computer cluster where a scheduler, in this case Slurm, is used to submit compute tasks, called jobs, to one or more nodes in the cluster. Jobs are submitted to the cluster via the login node (axon.rc.zi.columbia.edu) as show in the example below.:
| Warning |
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| title | The login node (axon.rc.zi.columbia.edu) is for job preparation, not for computation only preparation! |
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The login node is for has limited CPU and memory resources, and should only be used for the preparation of compute jobs, please don't run any cpu intensive tasks on the login node. Compute intensive preparation can be done via Slurm interactive jobs on the compute nodesbatch 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. |
Connecting via SSH
SSH (Secure Shell ), a secure protocol to used primarily to connect to Linux servers, is the way to connect Axon to submit jobs. Connecting via SSH is typically done from the command line interface such as Command Prompt in Windows or Terminal on the Mac (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 and running the command ssh as shown below. Windows users: SSH was only added to Windows 10 recently, so if you're somehow using an older version of Windows a third Older versions of Windows may require a third-party program such as Putty or MobaXtermis required to connect.. 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 VPN
The Axon login node can be accessed when you are on the Columbia campus or using the VPN by using command below:
| Code Block |
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| language | bash |
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| theme | FadeToGrey |
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| title | To login to the cluster ssh into the login node (replace aa3301 with your uni) |
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➤ 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 is available can be accessed anywhere outside by connecting via ssh to axon-remote.rc.zi.columbia.edu on port 55, as shown in the command below.the internal Columbia network by using command below:
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| language | bash |
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| theme | Midnight |
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> 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!
... |
While this command can be a lot to type using the You can make an ssh config file you can to abbreviate the above command to make it easier to connect to. By adding the following lines to the file creating a file named ~/.ssh/config config (create it if it doesn't already exist) you can connect using the a shorter name.:
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| language | bash |
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| title | Sample .ssh config to connect to axon remotely |
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Host axon-remote
HostName axon-remote.rc.zi.columbia.edu
User aa3301
# change aa3301 above to your uni
Port 55 |
Once you have the file have ~/.ssh/config in place you can run the abbreviated ssh command as shown below.:
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| language | bash |
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| theme | Midnight |
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| title | Connecting using the ~/.ssh/config example above |
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> 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!
... |
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| Info |
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| title | Connectivity from outside Columbia |
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While ssh 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. |
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