When you're installing k3s, it provides you the StorageClass "local-path", which is also set as the default StorageClass. This configuration is absolutely fine for a small, single node development cluster, but it is not suitable for a production grade multi-node cluster.
There are now two options after you've setup a custom, production ready StorageClass: change the default to your new StorageClass or delete the local-path StorageClass entirely, as you probably wont use it at all. The latter is the more likely case.
To remove the local-path StorageClass, create in the k3s manifests folder on all your master nodes (
/var/lib/rancher/k3s/server/manifests) a new empty file called
As soon as you've created the file, k3s will notice the change and removes the StorageClass, after which you can set your preferred StorageClass as the new default.