This can be used on almost anything, since Gluster is a userspace tool, based on FUSE. This means that all Gluster appears as to any application is just a directory.
Applications don't need specific support for Gluster, so long as you can tell the application to use a certain directory for storage.
One application can be for redundant and scaled storage, including for within Docker and Kubernetes, LXC, Proxmox, OpenStack, etc or just your image/web/video files or even da........
Unless you are using OpenStack, AWS etc then cloud-init is just some bloat that slows down the booting of your VMand can actually halt it from booting if it doesn't have a proper working IP (not good!).
#remove cloud init!
Debian based Ubuntu / Mint
sudo apt remove cloud-init
RHEL / CentOS based
yum remove cloud-init
........