[QUESTION] Can longhorn be used across clusters

[wangch1030]

Question

• The Longhorn deployed in Harvester is designed to work within the cluster, making it difficult to identify disks outside the cluster.
• Reference link: [QUESTION] Can longhorn be used across clusters？ #2192
• Have any changes been made to cross cluster usage of longhorn within the Harvester cluster at this stage

[ejweber]

Converted to a discussion.

Longhorn has not taken any steps towards usage across clusters since the linked issue. It is still the Longhorn design philosophy that it provides highly available storage WITHIN a cluster (though features like Disaster Recovery Volumes can be used to allow a secondary cluster to quickly takeover in the event of the failure of a primary cluster.

For downstream clusters within a Harvester cluster, I think the Harvester team generally intends for users to install the Harvester CSI driver backed by a Longhorn storage class in the Harvester cluster itself. This allows Longhorn to operate at (and manage redundancy at) the level of the physical disk.