How to Use an SSH Key with Non-root Users

Introduction

You can SSH to your Linux instance as root with the key. However, the key doesn’t work for non-root users.

So we will illustrate two methods to use SSH keys with non-root users.

Method 1: Create a New SSH Key

Just follow the steps below

• SSH to your Linux instance as a root
• Create an SSH key for a user

sudo -u ssh_user ssh-keygen

For example

sudo -u unixcop ssh-keygen

• Then save the private key, /home/ssh_user/.ssh/id_rsa , to your computer.

For example:

Copy it to your local .ssh folder as ~/.ssh/ssh_user_id_rsa

• Delete the private key from your Linux instance with the below command.

rm /home/ssh_user/.ssh/id_rsa

• Rename the public key to authorized_keys.

mv /home/ssh_user/.ssh/id_rsa.pub /home/ssh_user/.ssh/authorized_keys

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

ssh -i ~/.ssh/ssh_user_id_rsa ssh_user@192.168.13.135

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

Here, We will move the root key to the ssh_user, which also disables the root user’s SSH key access.

So just follow the steps below:

1. SSH to Linux instance as root.
2. Create the .ssh directory for ssh_user.

mkdir /home/ssh_user/.ssh

• Move the root key to ssh_user’s SSH directory.

mv /root/.ssh/authorized_keys /home/ssh_user/.ssh/

• Change the ownership of the .ssh directory from root to ssh_user so OpenSSH can read.

chown -R ssh_user:ssh_user /home/ssh_user/.ssh

Conclusion

In this short tutorial, We explained two methods to use SSH keys with non-root users.

Thank you!!