Tutorial on setting up public key for lab machines

Created by Run Chen (runchen@cs.columbia.edu)

Modified on March 28, 2024

1. Create a public key on your local machine

Check if any public key already existed on your local machine


        $ cd ~/.ssh 
        $ ls

You're looking for a pair of files named something like id_dsa or id_rsa and a matching file with a .pub extension. The .pub file is your public key, and the other file is the corresponding private key. If you don't have these files (or you don't even have a .ssh directory), you can create them by running a program called ssh-keygen, which is provided with the SSH package on Linux/macOS systems and comes with Git for Windows: 


        $ ssh-keygen -t ed25519

You will then be prompted to enter a secure passphrase, but you can leave that blank. You should now have a id_ed25519.pub file which contains your new public SSH key.


        $ cat ~/.ssh/id_ed25519.pub
        ssh-ed25519 [KEY] [USERNAME]@[LOCAL_MACHINE].local

Copy the entire line to your clipboard.

2. Add the public key to our lab remote machine

Log onto the remote lab machine assigned to you. 


        $ ssh [USER]@[LAB_MACHINE].cs.columbia.edu

If your account on the remote system doesn't already contain a ~/.ssh/authorized_keys file, create one; on the command line, enter the following commands:


        $ mkdir -p ~/.ssh
        $ touch ~/.ssh/authorized_keys

Then add what you copied from id_ed25519.pub on your local machine to the authorized_keys file.

3. Set up SSH on Visual Studio Code

Install the extension The Remote - SSH extension is used to connect to SSH hosts.

References:

[1] https://docs.github.com/en/authentication/connecting-to-github-with-ssh/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent?platform=linux

[2] https://git-scm.com/book/en/v2/Git-on-the-Server-Generating-Your-SSH-Public-Key