02 Connecting to (and navigating in) the JAX HPC environment

Overview

Teaching: 10 min
Exercises: 0 min

Questions

• How to connect to a remote system?

• What do I do on the command line?

Objectives

• Connect to the cluster via terminal and SSH

SSH Basics

The take home from this lesson.

• Use the command ssh <username>@<remote server IP address|domain name> to connect to a remote server.

The details on how ssh works.

• The (local) client asks the remote server (sumhpc login node) to establish a connection.
• The server and the client work together to encrypt the contents of data transferred through the connection.

Example ssh connection for this class

• Open terminal

• type ssh <username>@<login node name> where use name is your username on the remote system and the login node name (provided by instructor).

• Notice the first time you connect to a new machine you may get asked the following question (example listed below).

[user@edu-vm-63d1410f-2 ~]$ ssh user@35.227.70.171
The authenticity of host '35.227.70.171 (35.227.70.171)' can\'t be established.
ECDSA key fingerprint is SHA256:UTHv5IOvrF9uvxuh9Fo8uW2bx0BwCRLyrwHhONoiIj8.
ECDSA key fingerprint is MD5:15:bb:25:2a:3a:45:f4:c7:df:21:26:37:12:66:79:77.
Are you sure you want to continue connecting (yes/no)?

• Now your connected to the remote system, commands issued into the prompt are now being executed on the remote system.

• You are now on the login node notice the change in the prompt.

• Do not run programs on the login nodes. We use the login node to access the compute nodes with srun and submit batch jobs with sbatch.

• Lets take a look around the directories.

• Take a look at the home directory:
  ls ~

• Take a look at the fastsrcatch directory:
  ls /fastscratch

• Take a look at the fastsrcatch directory:
  ls /projects

• You can remain logged in for the rest of the tutorial, but when your ready to exit, just issue the ```exit`` to the prompt.

SFTP

SFTP stands for secure file transfer protocol and is used to transfer files from one computer to another.

MobaXtem will automatically establish and sftp session when ssh’ing into a remote system. It is visible as a yellow globe on the left hand side of the MobaXterm terminal.

Key Points

• ssh is the preferred way to connect to linux servers

• ssh is secure and protects information sent

• sftp available in a command line application and in GUI based applications for file transfers