You can disable GUI at system startup. Before you start modifying system settings, I recommend creating a snapshot of your droplet. You would be able to restore droplet if something went wrong. Note that you will be charged for the time when snapshot exists. It is not expensive to have a snapshot for a short period of time, unless its size is huge.
Here are the the steps to disable GUI at system startup.
1. In DO control panel switch to recovery environment (Boot from Recovery ISO), and launch recovery console.
2. Choose from menu Mount Your Disk Image(something like /dev/vda1 should appear next to the menu item), and then enter Interactive Shell.
3. Change root directory for your droplet’s one. But before that, bind some system resources. Execute following commands
mount -o bind /dev /mnt/dev
mount -o bind /dev/pts /mnt/dev/pts
mount -o bind /proc /mnt/proc
mount -o bind /sys /mnt/sys
mount -o bind /run /mnt/run
Now, your are in your droplet’s root directory. Be careful because you are acting as a root.
4. Disable GUI.
Run the following command:
systemctl set-default multi-user
You should get a message like that:
Created symlink /etc/systemd/system/default.target → /lib/systemd/system/multi-user.target.
5. Exit your chrooted environment.
6. Shutdown recovery environment
shutdown -h now
7. Switch to normal mode (Boot from Hard Drive). Launch DO console. CLI should be available again :)
Let me know how it works, pls.