My understanding is that Longhorn uses storage/disk of the k8s nodes it is running on. (/var/lib/longhorn/)
Can that location be changed to something like $nfs_mount_point ( /mnt/nfs_mount_1)
Yes. You can config the disks Longhorn uses for each node on Node page. Or you can modify the default disk path on Setting page. For the advanced disk config, you can refer to this doc: Longhorn | Documentation
But when I’m using a shared nfs mount across 3 nodes, longhorn is unable to attach the mount and it is going into a loop between attaching and detaching cycle.
We probably need more info about your environment. Can you help to create an issue with version, environment detail, and a support bundle?