OpenSSH

# 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

# 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

# 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