Rook is about using CSI... it doesn't run Ceph on Kubernetes. That's impossible because Ceph relies on functionality that exists in drivers (kernel modules) to run. CSI is the component that communicates between eg. rbd driver and the user-space (eg. Kubernetes controllers), but it doesn't run Ceph.
It's in principle impossible to do anything about block devices in containers like those used by Kubernetes because those rely on Linux processes and associated namespaces. There isn't a Linux namespace for block devices, the closest you can get is the filesystem namespace. In other words, you cannot manage block devices purely in containers, you need some help from the host operating system. And this is why I mentioned CSIs in my previous post.
It does run Ceph on Kubernetes. How else would you describe deploying OSDs to linux servers via Kubernetes other than "Ceph on Kubernetes"?
> That's impossible because Ceph relies on functionality that exists in drivers (kernel modules) to run
This statement doesn't make sense. All linux applications require kernel functionality. Yes, to deploy Ceph, you must run Linux systems with the desired kernel modules. Turns out, Rook sets that up for ya! This statement exposes a somewhat deep misunderstanding of what Kubernetes is.
I run into you in every thread that mentions k8s and I sense extreme vitriol and a huge lack of experience / understanding. Don't mistake my future lack of replies for an unsaid "you've misunderstood".
It's in principle impossible to do anything about block devices in containers like those used by Kubernetes because those rely on Linux processes and associated namespaces. There isn't a Linux namespace for block devices, the closest you can get is the filesystem namespace. In other words, you cannot manage block devices purely in containers, you need some help from the host operating system. And this is why I mentioned CSIs in my previous post.