I am using a CentOS running on a Cloud Hosted Virtual Machine. The cloud hosting service is Digital Ocean. The cloud hosted VM dose not allow you to use full hard disk encryption as it dose not provide the ability to enter a password on booting the device.
To encrypt the device I was going to create a copy of a number of root directories (/lost+found, /run, /srv, /tmp and /var) and swap the encrypted directories in place of the original directories by mounting the encrypted copies in place of the original root directories. I was going to mount the encrypted directory's each time the device was booted.
I was going to use DM-Crypt and LUKS to encrypt and access the directories.
Is this an OK idea?