Knowledgebase

Introduction

RCS provides a feature that allows you to pre-install SSH keys when creating a new instance, so you can SSH to the instance as root with the key. However, the key doesn't work for non-root users. This tutorial describes three methods to use SSH keys with non-root users.

Requirements

• A RCS Linux or BSD instance

• A non-root user account (it is example_user in this tutorial)

Option 1: Create a New SSH Key

1. SSH to the instance as root.

2. Create an SSH key for example_user.

   # sudo -u example_user ssh-keygen
   
   Generating public/private rsa key pair.
   
   Enter file in which to save the key (/home/example_user/.ssh/id_rsa):
   
   Created directory '/home/example_user/.ssh'.
   
   Enter passphrase (empty for no passphrase):
   
   Enter same passphrase again:
   
   Your identification has been saved in /home/example_user/.ssh/id_rsa
   
   Your public key has been saved in /home/example_user/.ssh/id_rsa.pub
   

3. Save the private key, /home/example_user/.ssh/id_rsa, to your computer. For example, you might copy it to your local .ssh folder as ~/.ssh/example_user_id_rsa.

4. Delete the private key from your instance.

   # rm /home/example_user/.ssh/id_rsa
   

5. Rename the public key to authorized_keys.

   # mv /home/example_user/.ssh/id_rsa.pub /home/example_user/.ssh/authorized_keys
   

If you saved the private key as ~/.ssh/example_user_id_rsa, you can SSH to the server as your non-root example_user:

$ ssh -i ~/.ssh/example_user_id_rsa example_user@192.0.2.123

Option 2: Move the root SSH Key to the Non-root User

In this case, we'll move the root key to the example_user, which also disables the root user's SSH key access.

1. SSH to the instance as root.

2. Create the .ssh directory for example_user.

   # mkdir /home/example_user/.ssh
   

3. Move the root key to example_user's SSH directory.

   # mv /root/.ssh/authorized_keys /home/example_user/.ssh/
   

4. Change the ownership of the .ssh directory from root to example_user so OpenSSH can read it.

   # chown -R example_user:example_user /home/example_user/.ssh
   

Option 3: Use Startup Scripts

If you are deploying many instances, you may use the RCS Startup Scripts feature to create a non-root user and move the SSH key automatically.

Create a Startup Script

1. Select Scripts in the Customer Portal.

2. Click the plus button to create a new startup script.

3. Paste the following script.

   #!/bin/sh
   
   
   
   useradd -m -s /bin/bash example_user
   
   mv /root/.ssh /home/example_user/
   
   chown -R example_user:example_user /home/example_user/.ssh
   

You can deploy instances with this script and one or more SSH keys. When the instance deploys, the script creates example_user, then moves the public SSH keys from root to example_user. Now you can SSH to the new instance as example_user with the keys you provided.

More Information

For more information about managing SSH keys, see other guides:

• How to Generate SSH Keys

• Deploy a New Instance with an SSH Key

• Connect to an Instance with an SSH Key

• How to Add and Delete SSH Keys