SSH
- Lisa Stafford
Goal: Provide new HPC users with common steps to log into a cluster using SSH on Beartooth as an example.
What is SSH?
SSH stands for The Secure Shell Protocol. This is a network protocol for operating network services securely over an unsecured network. Typically users use ssh for remote access to HPC systems and ARCC users may use ssh to connect to our HPC resources. SSH allows one to login to a remote system, then remotely execute commands on the system, but virtually any network service can be secured with ssh.
SSH Clients
Your ssh client may be different than your neighbors. SSH clients differ between devices, OS versions, and end user preferences but they all use the same underlying protocol (SSH) to connect to remote servers.
Default Clients for common OS’s are shown below:
OS Versions | Ubuntu (Debian) Linux OS | Mac OS | Windows OS |
|---|---|---|---|
Default SSH Client | OpenSSH | Terminal | OpenSSH |
Popular User Installed SSH Clients | PuTTY, MobaXterm, Termius | Termius, iTerm2, CyberDuck | MobaXterm, Powershell, PuTTY |
Web browser SSH option | Client independent, in any web browser: OnDemand Shell Access | ||
Ex: SSH to Beartooth with ARCC Training Account
You have an Existing Account: Log on
Open up a terminal.
Use a client such as MobiXTerm
An ssh command in Command Line Interface is broken down into username, '@' symbol, and servername. As an example:
ssh arcc-t01@beartooth.arcc.uwyo.edu
[arcc-t01@mblog1 ~]$
# UW: Beartooth(blog1/blog2)In the above ssh example, we want to use ssh to connect with username arcc-t01 to servername beartooth.arcc.uwyo.edu
We can also get ssh access to HPC through a web browser:
Open up Chrome
Navigate to: MedicineBow On Demand
Start MedicineBow Shell Access
Ex: SSH enabling X11
Previously, we stated that additional network services can be secured with SSH. In the following example, we will connect using ssh to beartooth and enable X11 forwarding, which is a service allowing for graphics.
To use graphical applications on the remote system you will need to enable X11 forwarding. To do this with ssh you can look up in the manual to see what flag you need to add by typing man ssh.
Looking at the options we can find we can use a capital 'X' flag -X to enable X11 forwarding and a capital 'Y' flag -Y for secure X11 forwarding. Which one to use is up to you, but in most cases -X will be sufficient. If you are on a mac, you will need to use -Y. See the example below:
ssh -X arcc-t01@medicinebow.arcc.uwyo.edu