Description

Ok, we have a task to configure PVE Cluster, which consists of several PVE nodes, and we must have the following features:

A shared network storage, attached to an each node in the Cluster. The content of the storage must be synced between nodes immediately (if it is the same image (iSCSI or RBD, for example), attached to an each node), or with some delay (GlusterFS, for example).
We must have an opportunity to create VM on a network shared storage.
In case of failing a node, which contains VM, we must have an opportunity to run this VM on another node in the Cluster.

Configuring

First off, you need to configure PVE Cluster: Proxmox. Кластер

Creating Ceph RBD pool

Attaching RBD to PVE (as a Shared storage)

Now you can create VM with RAW disk type.

Create iSCSI-target. For example, at XigmaNAS or at Ceph

During adding iSCSI shared disk check "Use LUNs directly".

Now you are able to add the whole iSCSI-disk as a separated disk for the only one VM.

You can make instant Migration to any node in the Cluster.

But you still can't create Snapshots. So it's useless for some cases.

+ Snapshots work (but you can only rollback to the LATEST snapshot, this is ZFS limitation, nothing you can do about it)
+ Migration works

Install ZFS

Configure iSCSI-target server and attach storage to PVE Cluster