> ## Documentation Index
> Fetch the complete documentation index at: https://coollabstechnologiesbt.mintlify.site/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# OpenSSH

> A guide to configure OpenSSH for Coolify.

Coolify uses SSH to connect to your server and deploy your application, even if you are using only the `localhost` server - where Coolify is running on.

To validate your configuration, make sure the followings are set on your server.

<Warning>Some commands may vary based on your Linux distribution.</Warning>

<Warning>
  Make sure the SSH key does not have a passphrase. Connection will fail if the
  key has a passphrase.
</Warning>

<Steps>
  <Step title="SSH Enabled">
    Make sure SSH is enabled and you can connect to your server with SSH from your local machine with root user.

    ```bash

    # Ubuntu/Debian

    sudo apt install openssh-server
    sudo systemctl status sshd

    # CentOS/RHEL

    sudo yum install openssh-server
    sudo systemctl status sshd

    # Arch Linux

    sudo pacman -S openssh
    sudo systemctl status sshd

    # Alpine Linux

    sudo apk add openssh
    sudo rc-service sshd status

    # SLES/openSUSE

    sudo zypper install openssh
    sudo systemctl status sshd

    ```
  </Step>

  <Step title="Root Login">
    Make sure `PermitRootLogin` is set to `yes` or `without-password` or `prohibit-password`  in `/etc/ssh/sshd_config` file.

    ```bash
    # Check the current value
    grep PermitRootLogin /etc/ssh/sshd_config

    # If the value is not `yes` or `without-password` or `prohibit-password`, change it and make sure it is not commented out.
    # If it is commented out, remove the `#` character at the beginning of the line.

    sudo vi /etc/ssh/sshd_config

    # You can exit the editor by pressing `Esc` and then `:wq` and then `Enter` keys - thank me later.

    # Restart the SSH service
    # Ubuntu/Debian/CentOS/RHEL/Arch Linux/SLES/openSUSE
    sudo systemctl restart sshd

    # Alpine Linux
    sudo rc-service sshd restart

    ```
  </Step>

  <Step title="SSH Key set on the Server">
    Make sure an SSH key is added to the `~/.ssh/authorized_keys` file.
    If you installed Coolify with the automated script, you don't need to do anything else.

    If you installed Coolify manually, you need to add an SSH key to the `~/.ssh/authorized_keys` file.

    <Warning>
      Make sure the SSH key does not have a passphrase. Connection will fail if the
      key has a passphrase.
    </Warning>

    ```bash
    # Create a new SSH key pair ed25519 (recommended) or rsa (legacy) with the following command.

    # The key needs to be created in the `/data/coolify/ssh/keys` directory with,
    # id.root@host.docker.internal name,
    # no passphrase,
    # root@coolify comment.

    ssh-keygen -t ed25519 -a 100 -f /data/coolify/ssh/keys/id.root@host.docker.internal -q -N "" -C root@coolify
    chown 9999 /data/coolify/ssh/keys/id.root@host.docker.internal

    # Copy the public key to the `authorized_keys` file
    cat /data/coolify/ssh/keys/id.root@host.docker.internal.pub >>~/.ssh/authorized_keys

    # Set the correct permissions
    chmod 600 ~/.ssh/authorized_keys
    chmod 700 ~/.ssh
    ```
  </Step>

  <Step title="SSH Key set in Coolify">
    Add the private key to Coolify at `Keys & Tokens` menu -> `Private Keys` and set this new key in the localhost server settings.
  </Step>
</Steps>