1. GKE clusters must use Ubuntu OS instead of Container-Optimized OS, in order to satisfy Longhorn open-iscsi dependency.

2. GKE requires a user to manually claim themselves as cluster admin to enable RBAC. Before installing Longhorn, run the following command:

kubectl create clusterrolebinding cluster-admin-binding --clusterrole=cluster-admin --user=<name@example.com>

where name@example.com is the user’s account name in GCE. It’s case sensitive. See this document for more information.