Ubuntu Linux - Shared VHDX

Setup a third machine that acts as a NFS server (or use one of the servers as NFS server). Normal Linux file systems can not be mounted from multiple machines.

You can’t share block device with non-clustered file system like NTFS, ReFS, Ext3/4 or ZFS on top... There’s nobody to arbiter concurrent writes, metadata updates etc. Good story here:

https://forums.starwindsoftware.com/viewtopic.php?f=5&t=1392

So either you switch to clustered file system or use network redirector like f.e. SMB3 or NFS.