message: Add longhorn installation instructions
diff: @@ -40,3 +40,24 @@ Here is a brief overview on how to create a cluster on Hetzner's cheap cloud sto
  1. For any non-master node, run `curl -sfL https://get.k3s.io | K3S_URL=https://${SERVERIP}:6443 K3S_TOKEN=${NODETOKEN} sh -`, replacing `${SERVERIP}` with the master node's IP and `${NODETOKEN}` with the previously mentioned token.
  Setting `KUBECONFIG` to the path of the downloaded kubeconfig and running `kubectl get nodes` should show all nodes as online shortly after.
  +
  +### Enabling storage
  +
  +The final step is to create a storage provider, for which we will be using Longhorn. This is required to be able to offer persistent storage on nodes, see the [Longhorn example in the k3s docs](https://rancher.com/docs/k3s/latest/en/storage/) for details.
  +
  +The prerequisite is that the `open-iscsi` is installed **on the node itself**. Thus we enter each node and install it:
  +
  +```console
  +# Shortcut to get node IPs
  +NODE_IPS=$(kubectl get nodes -o 'jsonpath={.items[*].status.addresses[?(@.type=="InternalIP")].address}')
  +for IP in ${NODE_IPS}; do
  + ssh root@$IP "hostname; apt-get -qq update && apt-get -qq install open-iscsi";
  +done;
  +# ...
  +```
  +
  +With `iscsi` installed, we can now deploy longhorn:
  +
  +```console
  +$ kubectl apply -f https://raw.githubusercontent.com/longhorn/longhorn/master/deploy/longhorn.yaml
  +```
  