All website data is stored in /var/www - this can be a separate partition or mount point. If you have an existing server and you want to move /var/www to it, this is possible manually. Something like this. These instructions were hand written by me and might contain errors - make sure you understand the commands you are running and check your backups before proceeding.
Firstly, stop services:
systemctl stop enhcontrold
systemctl stop appcd
systemctl stop docker
Now rename the old /var/www and make an empty /var/www in its place
mv /var/www /var/www_old
mkdir /var/www
Now attach the new storage with the cloud provider. You should see its device path in the output of lsblk. Edit /etc/fstab and create a new mount for the new storage on /var/www. Example:
/dev/sdc /var/www defaults 0 0
You may also want to add the _netdev option.
Now move the website data back
mv /var/www_old/* /var/www/
And lastly start your services up:
systemctl start docker
systemctl start appcd
systemctl start enhcontrold
