I have a 3 node k8s cluster and having a remote storage box with additional disks connected to it. I want to utilize these disks. So is this use case supported on OpenEBS? Also, do I have to attach the disks to Node before deploying OpenEBS? Is this a prerequisites?
Yes OpenEBS support storage with additional disks connected. With 0.7 it has a feature NDM (Node Disk Manager) which would monitor the disks attached to the nodes. Once the disks are attached you can create a pool on top of it and use the same. For more details, document link
Sure. It's supported and you need the disk attached when you setup OpenEBS as your block storage.
After you set it up, essentially you can create volumes (pvcs, pvs) for Kubernetes and mount them on your pods for consumption.
You can setup OpenEBS on Kubernetes cluster where you run your workloads either using helm or kubectl