Note: _replace {{server}} with your domain or ip_

* Login as the ec2-user
```
ssh -i key.pem ec2-user@{{server}}
```
* Switch to administrator
```
sudo -i
```
* Load the configuration file
```
sudo vi /etc/ssh/sshd_config
```
* Make sure these are enabled: 

```
	PermitRootLogin yes
	# Only allow root to run commands over ssh, no shell
	#PermitRootLogin forced-commands-only
	RSAAuthentication yes
	PubkeyAuthentication yes
	AuthorizedKeysFile     .ssh/authorized_keys
```
* copy your local public key to the authorized list
```
cat ~/.ssh/id_rsa.pub | ssh root@{{server}} 'cat - >> ~/.ssh/authorized_keys'
```
* Make sure the files have the right permisions 
```
chmod 600 ~/.ssh/authorized_keys && chmod 700 ~/.ssh/
```
* Restart the service
```
sudo service sshd reload
```
* Exit and try to login again
```
exit
ssh root@{{server}}
```