r2u-ssh

This repository builds a Docker image based on rocker/r2u that enables:

• SSH access using a base64-encoded public key via AUTHORIZED_KEYS_B64
• sudo installed and configured (NOPASSWD) for the main user
• bspm enabled in R with the sudo backend
• A minimal boot script (boot-sshd.sh) that prepares ~/.ssh and starts sshd

The primary purpose of this image is to enable an R environment with Ubuntu Binaries to run in Positron via SSH.

---

Step 1 - Clone this repository

In terminal (bash/powershell):

git clone https://github.com/jmgirard/r2u-ssh.git
cd r2u-ssh

Step 2 - Create an SSH key

In terminal (bash/powershell):

ssh-keygen -t ed25519 -C "[email protected]"

Be sure to replace the example email address with your own. Hit enter/return to accept all defaults

Step 3 - Encode your public key

Create a .env file at the repo root containing your base64-encoded public key:

macOS/Linux:

{
  echo -n "AUTHORIZED_KEYS_B64="
  if base64 --help 2>&1 | grep -q '\-w'; then
    base64 -w0 ~/.ssh/id_ed25519.pub
  else
    base64 < ~/.ssh/id_ed25519.pub | tr -d '\n'
  fi
  echo
  echo "USERNAME=rocker"
} > .env

Windows (PowerShell):

$pub = Get-Content -Raw "$env:USERPROFILE\.ssh\id_ed25519.pub"
$base64 = [Convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes($pub))
"AUTHORIZED_KEYS_B64=$base64" | Out-File -Encoding ascii .env
"USERNAME=rocker" | Out-File -Append -Encoding ascii .env

Step 4 - Build the image

In terminal (bash/powershell):

docker compose up -d --build

Step 5 - Connect in Positron

1. Open Positron
2. Go to Remote Explorer (left pane)
3. Click on the "Configure" (gear) icon to open SSH config
4. Paste the following in:

Host r2u-ssh
  HostName 127.0.0.1
  Port 2222
  User rocker
  IdentityFile ~/.ssh/id_ed25519
  IdentitiesOnly yes

4. Click the Refresh (cycle) icon
5. Click Connect to Host in New Window (window plus) icon next to r2u-ssh

You'll now be connected to a full R environment running inside Docker.

Step 6 - Cleanup

To close the container but keep the image, use:

docker compose down

To close the container and remove the image, use:

docker compose down --rmi all