Single node cluster adjustments

Update the following changes, then commit and push.

Reduce Longhorn replica count

Set the defaultClassReplicaCount to 1:

system/longhorn-system/values.yaml

longhorn:
  defaultSettings:
    nodeDownPodDeletionPolicy: delete-both-statefulset-and-deployment-pod
  persistence:
    # If you have three or more nodes for storage, use 3; otherwise use 2
    defaultClassReplicaCount: 3  # TODO run DR test to see if we actually need 3

Disable automatic upgrade for OS and k3s

Because they will try to drain the only node, the pods will have no place to go. Remove them entirely:

rm -rf system/kured
rm -rf system/system-upgrade

Commit and push the change. You can revert it later when you add more nodes.