fix: reverted NodeGetInfo response as it breaks Nomad clusters (#776)

We modified the response for `NodeGetInfo` to return an additional
Topology Segment. We assumed that this only “adds” new info, but in
practice it breaks the spec.

When trying to schedule a volume to nodes, the container orchestration
systems should verify that the Node fulfills at least one Accessible
Topology of the Node, where “fulfills” means that all supplied segments
match.

This is not implemented in the same way between Kubernetes and Nomad.

- **Kubernetes**: requirements are fulfilled if the volume specifies a
subset of the Nodes topology
- **Nomad**: requirements are fulfilled if the volume specifies all of
the Nodes topology

We made these changes to work around a bug in the Kubernetes scheduler
([here](kubernetes-csi/external-provisioner#544))
where nodes without the CSI Plugin would still be considered for
scheduling, but then creating and attaching the volume fails with no
automatic reconciliation of this error.

chart/templates/core/storageclass.yaml

@@ -10,13 +10,6 @@ provisioner: csi.hetzner.cloud
 volumeBindingMode: WaitForFirstConsumer
 allowVolumeExpansion: true
 reclaimPolicy: {{ $val.reclaimPolicy | quote }}
-{{- if $val.allowedTopologyCloudServer }}
-allowedTopologies:
-- matchLabelExpressions:
-  - key: instance.hetzner.cloud/provided-by
-    values:
-    - "cloud"
-{{- end }}
 ---
 {{- end }}
 {{- end }}

chart/values.yaml

@@ -728,5 +728,3 @@ storageClasses:
   - name: hcloud-volumes
     defaultStorageClass: true
     reclaimPolicy: Delete
-    ## @param storageClass.allowedTopologyCloudServer Prevents pods from being scheduled on nodes, specifically Robot servers, where Hetzner volumes are unavailable
-    allowedTopologyCloudServer: false 

docs/kubernetes/README.md

@@ -209,19 +209,9 @@ $ kubectl apply -f https://raw.githubusercontent.com/hetznercloud/csi-driver/v2.
 
 ## Integration with Root Servers
 
-Root servers can be part of the cluster, but the CSI plugin doesn't work there and the current behaviour of the scheduler can cause Pods to be stuck in `Pending`.
+Root servers can be part of the cluster, but the CSI plugin doesn't work there.
 
-In the Helm Chart you can set `allowedTopologyCloudServer` to true to prevent pods from being scheduled on nodes, specifically Robot servers, where Hetzner volumes are unavailable. This value can not be changed after the initial creation of a storage class.
-
-```yaml
-storageClasses:
-  - name: hcloud-volumes
-    defaultStorageClass: true
-    reclaimPolicy: Delete
-    allowedTopologyCloudServer: true # <---
-```
-
-To ensure proper topology evaluation, labels are needed to indicate whether a node is a cloud VM or a dedicated server from Robot. If you are using the `hcloud-cloud-controller-manager` version 1.21.0 or later, these labels are added automatically. Otherwise, you will need to label the nodes manually.
+Labels are needed to indicate whether a node is a cloud VM or a dedicated server from Robot. If you are using the `hcloud-cloud-controller-manager` version 1.21.0 or later, these labels are added automatically. Otherwise, you will need to label the nodes manually.
 
 ### Adding labels manually
 

internal/driver/driver.go

@@ -9,5 +9,4 @@ const (
 	DefaultVolumeSize = MinVolumeSize
 
 	TopologySegmentLocation = PluginName + "/location"
-	ProvidedByLabel         = "instance.hetzner.cloud/provided-by"
 )

internal/driver/node.go

@@ -178,7 +178,6 @@ func (s *NodeService) NodeGetInfo(_ context.Context, _ *proto.NodeGetInfoRequest
 		AccessibleTopology: &proto.Topology{
 			Segments: map[string]string{
 				TopologySegmentLocation: s.serverLocation,
-				ProvidedByLabel:         "cloud",
 			},
 		},
 	}