HPC via VS Code

HPC via VS Code#

Using VS Code to connect to remote SSH machines is a significant quality of life improvement over direct SSH access via the terminal as it enables:

  • GUI based editing of files on the remote filesystem

  • Ability to manage multiple terminals without authenticating each one

These benefits do come with a slightly more involved setup process.

  1. Install and be familiar with VS Code - if you are here we will assume you’ve already using VS Code.

  2. Install the “Remote - SSH” extension from Microsoft. It should be the first option that appears if you search “ssh”

  3. Have a correctly configured openssh configuration. This requires a C:\Users\your.name.ssh directory to exist and have the following two files

    1. C:\Users\your.name.ssh\config - The openssh configuration file (see example below)

    2. C:\Users\your.name.ssh\id_rsa - Your private ssh key - the public half of your key should already have been uploaded to lcrc accounts page.

  4. Enable “Show Login Terminal” in the config (Ctrl+,). Search for this option (part of Extensions > Remote - SSH) and make sure that the “Always reveal the ssh login window” option is checked

With the above in place you can start a connection to a HPC cluster with

  1. Open Command palette (Ctrl-Shift-P) and select “Remote-SSH Connect Current Window to Host” or “Remote-SSH Connect to Host”

  2. Select the correct host from the drop down list (list is populated from your config file)

  3. Confirm it is a “linux” host

  4. When the terminal pops up a Duo request dialog, choose option 1 (type 1 and press enter)

After you are connected you can open a folder on the remote system (like your home directory or a checked out version of polaris-studio) and then edit files in that directory as if it was a local filesystem.

You can also launch multiple terminals (including split terminals) using the standard VS Code terminal interface without having to re-authenticate.

You can see which type of VS Code project you are currently operating in (local, “Remote - WSL”, or “Remote - SSH”) by checking the green connection icon in the very bottom left of the status bar. An example of each of the three types is shown below. This green section can also be clicked as a shortcut to bring up the “Remote” connection commands.

Status Bar

Example SSH Config#

An Example ssh config file which would live at c:\Users\your.user.ssh\config. Make sure to change your.user and id_rsa name (if non-standard).

# Enable hostname canonicalization for all connections
CanonicalizeHostname yes
CanonicalDomains lcrc.anl.gov

Host *
    pubkeyacceptedkeytypes +rsa-sha2-256,rsa-sha2-512

# =================================
# Settings for all LCRC HPC systems
# =================================

Host *.lcrc.anl.gov
    User your.user
    IdentityFile ~/.ssh/id_rsa.lcrc
    ForwardAgent true
    MACs hmac-sha2-512

Host logins logins.lcrc.anl.gov
    HostName logins.lcrc.anl.gov

Host bebop
    HostName bebop.lcrc.anl.gov
    ProxyJump logins.lcrc.anl.gov
  
Host crossover
    HostName crossover.lcrc.anl.gov
    ProxyJump logins.lcrc.anl.gov

Host improv
    HostName ilogin1.lcrc.anl.gov
    ProxyJump logins.lcrc.anl.gov
  
Host swing
    HostName swing.lcrc.anl.gov

Example of Login dialog#

Below is what you should see in the terminal when your connection attempt is successfully attempting authentication with the login server. Type 1 and press enter to select the one and only option.

***********************************************************************************
* This machine accepts SSH public key + Duo MFA only.                             *
* If you do not have an SSH key and Duo set up, you will not be able to login.    *
*                                                                                 *
* See https://docs.lcrc.anl.gov for more information.                             *
***********************************************************************************
(james.cook@ilogin1.lcrc.anl.gov) Duo two-factor login for james.cook

Enter a passcode or select one of the following options:

 1. Duo Push to +XX XXX XXX 610

Passcode or option (1-1):

Exporting private key from Putty PPK#

If you have been using Putty previously you may only have a ppk rather than a standard public / private keypair. You can export an OpenSSH version by using puttygen.exe (should be in the same folder as your putty.exe):

  1. Open PuttyGen

  2. Click Load

  3. Load your private key

  4. Go to Conversions->Export OpenSSH and export your private key

  5. Copy your private key to ~/.ssh/id_dsa.lcrc