✨ Add constant hostnames to bare metal servers

api/v1beta1/hetznercluster_types.go

@@ -29,6 +29,8 @@ const (
 	// AllowEmptyControlPlaneAddressAnnotation allows HetznerCluster Webhook
 	// to skip some validation steps for externally managed control planes.
 	AllowEmptyControlPlaneAddressAnnotation = "capi.syself.com/allow-empty-control-plane-address"
+	// ConstantBareMetalHostnameAnnotation makes hostnames of bare metal servers constant.
+	ConstantBareMetalHostnameAnnotation = "capi.syself.com/constant-bare-metal-hostname"
 )
 
 // HetznerClusterSpec defines the desired state of HetznerCluster.

controllers/hetznerbaremetalhost_controller.go

@@ -28,6 +28,7 @@ import (
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/klog/v2"
 	clusterv1 "sigs.k8s.io/cluster-api/api/v1beta1"
+	"sigs.k8s.io/cluster-api/util"
 	"sigs.k8s.io/cluster-api/util/conditions"
 	"sigs.k8s.io/cluster-api/util/predicates"
 	"sigs.k8s.io/cluster-api/util/record"
@@ -111,6 +112,15 @@ func (r *HetznerBareMetalHostReconciler) Reconcile(ctx context.Context, req ctrl
 	}
 
 	log = log.WithValues("HetznerCluster", klog.KObj(hetznerCluster))
+
+	// Fetch the Cluster.
+	cluster, err := util.GetClusterFromMetadata(ctx, r.Client, hetznerCluster.ObjectMeta)
+	if err != nil {
+		return reconcile.Result{}, fmt.Errorf("failed to get Cluster: %w", err)
+	}
+
+	log = log.WithValues("Cluster", klog.KObj(cluster))
+
 	ctx = ctrl.LoggerInto(ctx, log)
 
 	// Get Hetzner robot api credentials
@@ -128,11 +138,13 @@ func (r *HetznerBareMetalHostReconciler) Reconcile(ctx context.Context, req ctrl
 	if res != emptyResult {
 		return res, nil
 	}
+
 	// Create the scope.
 	hostScope, err := scope.NewBareMetalHostScope(scope.BareMetalHostScopeParams{
 		Logger:               log,
 		Client:               r.Client,
 		HetznerCluster:       hetznerCluster,
+		Cluster:              cluster,
 		HetznerBareMetalHost: bmHost,
 		RobotClient:          r.RobotClientFactory.NewClient(robotCreds),
 		SSHClientFactory:     r.SSHClientFactory,

controllers/hetznerbaremetalhost_controller_test.go

@@ -117,6 +117,7 @@ var _ = Describe("HetznerBareMetalHostReconciler", func() {
 						UID:        capiCluster.UID,
 					},
 				},
+				Labels: map[string]string{clusterv1.ClusterNameLabel: capiCluster.Name},
 			},
 			Spec: helpers.GetDefaultHetznerClusterSpec(),
 		}
@@ -647,6 +648,7 @@ var _ = Describe("HetznerBareMetalHostReconciler - missing secrets", func() {
 						UID:        capiCluster.UID,
 					},
 				},
+				Labels: map[string]string{clusterv1.ClusterNameLabel: capiCluster.Name},
 			},
 			Spec: helpers.GetDefaultHetznerClusterSpec(),
 		}

controllers/hetznerbaremetalmachine_controller_test.go

@@ -107,6 +107,7 @@ var _ = Describe("HetznerBareMetalMachineReconciler", func() {
 						UID:        capiCluster.UID,
 					},
 				},
+				Labels: map[string]string{clusterv1.ClusterNameLabel: capiCluster.Name},
 			},
 			Spec: helpers.GetDefaultHetznerClusterSpec(),
 		}
@@ -160,7 +161,6 @@ var _ = Describe("HetznerBareMetalMachineReconciler", func() {
 			Err:    nil,
 		})
 		osSSHClient.On("GetCloudInitOutput").Return(sshclient.Output{StdOut: "dummy content of /var/log/cloud-init-output.log"})
-
 	})
 
 	AfterEach(func() {

controllers/hetznerbaremetalremediation_controller_test.go

@@ -130,6 +130,7 @@ var _ = Describe("HetznerBareMetalRemediationReconciler", func() {
 						UID:        capiCluster.UID,
 					},
 				},
+				Labels: map[string]string{clusterv1.ClusterNameLabel: capiCluster.Name},
 			},
 			Spec: getDefaultHetznerClusterSpec(),
 		}

docs/topics/hetzner-baremetal.md

@@ -382,3 +382,13 @@ default     my-cluster-md-1-cp2fd-7nld7      my-cluster   bm-my-cluster-md-1-d75
 default     my-cluster-md-1-cp2fd-n74sm      my-cluster   bm-my-cluster-md-1-l5dnr         hcloud://bm-2105469   Running        10h   v1.27.7
 ```
 Please note that hcloud servers are prefixed with `hcloud://` and baremetal servers are prefixed with `hcloud://bm-`.
+
+## Advanced
+
+### Constant hostnames for bare metal servers
+
+In some cases it has advantages to fix the hostname and with it the names of nodes in your clusters. For cloud servers not so much as for bare metal servers, where there are storage integrations that allow you to use the storage of the bare metal servers and that work with fixed node names. 
+
+Therefore, there is the possibility to create a cluster that uses fixed node names for bare metal servers. Please note: this only applies to the bare metal servers and not to Hetzner Cloud servers.
+
+You can trigger this feature by creating a `Cluster` with the annotation `"capi.syself.com/constant-bare-metal-hostname": "true"`. This is still an experimental feature but it should be save to use and to also update existing clusters with this annotation. All new machines will be created with this constant hostname.

pkg/scope/baremetalhost.go

@@ -25,6 +25,7 @@ import (
 	"github.com/go-logr/logr"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/types"
+	clusterv1 "sigs.k8s.io/cluster-api/api/v1beta1"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 
 	infrav1 "github.com/syself/cluster-api-provider-hetzner/api/v1beta1"
@@ -39,6 +40,7 @@ type BareMetalHostScopeParams struct {
 	Logger               logr.Logger
 	HetznerBareMetalHost *infrav1.HetznerBareMetalHost
 	HetznerCluster       *infrav1.HetznerCluster
+	Cluster              *clusterv1.Cluster
 	RobotClient          robotclient.Client
 	SSHClientFactory     sshclient.Factory
 	OSSSHSecret          *corev1.Secret
@@ -58,6 +60,9 @@ func NewBareMetalHostScope(params BareMetalHostScopeParams) (*BareMetalHostScope
 	if params.HetznerCluster == nil {
 		return nil, errors.New("cannot create baremetal host scope without Hetzner cluster")
 	}
+	if params.Cluster == nil {
+		return nil, errors.New("cannot create baremetal host scope without cluster")
+	}
 	if params.RobotClient == nil {
 		return nil, errors.New("cannot create baremetal host scope without robot client")
 	}
@@ -79,6 +84,7 @@ func NewBareMetalHostScope(params BareMetalHostScopeParams) (*BareMetalHostScope
 		RobotClient:          params.RobotClient,
 		SSHClientFactory:     params.SSHClientFactory,
 		HetznerCluster:       params.HetznerCluster,
+		Cluster:              params.Cluster,
 		HetznerBareMetalHost: params.HetznerBareMetalHost,
 		OSSSHSecret:          params.OSSSHSecret,
 		RescueSSHSecret:      params.RescueSSHSecret,
@@ -95,6 +101,7 @@ type BareMetalHostScope struct {
 	SSHClientFactory     sshclient.Factory
 	HetznerBareMetalHost *infrav1.HetznerBareMetalHost
 	HetznerCluster       *infrav1.HetznerCluster
+	Cluster              *clusterv1.Cluster
 	OSSSHSecret          *corev1.Secret
 	RescueSSHSecret      *corev1.Secret
 }
@@ -128,3 +135,18 @@ func (s *BareMetalHostScope) GetRawBootstrapData(ctx context.Context) ([]byte, e
 
 	return value, nil
 }
+
+// Hostname returns the desired host name.
+func (s *BareMetalHostScope) Hostname() (hostname string) {
+	if s.hasConstantHostname() {
+		hostname = fmt.Sprintf("%s%s-%v", infrav1.BareMetalHostNamePrefix, s.Cluster.Name, s.HetznerBareMetalHost.Spec.ServerID)
+	} else {
+		hostname = infrav1.BareMetalHostNamePrefix + s.HetznerBareMetalHost.Spec.ConsumerRef.Name
+	}
+
+	return hostname
+}
+
+func (s *BareMetalHostScope) hasConstantHostname() bool {
+	return s.Cluster.GetAnnotations()[infrav1.ConstantBareMetalHostnameAnnotation] == "true"
+}

pkg/services/baremetal/host/host.go

@@ -1172,12 +1172,10 @@ func (s *Service) createAutoSetupInput(sshClient sshclient.Client) (autoSetupInp
 		return autoSetupInput{}, s.recordActionFailure(infrav1.ProvisioningError, msg)
 	}
 
-	hostName := infrav1.BareMetalHostNamePrefix + s.scope.HetznerBareMetalHost.Spec.ConsumerRef.Name
-
 	// Create autosetup file
 	return autoSetupInput{
 		osDevices: deviceNames,
-		hostName:  hostName,
+		hostName:  s.scope.Hostname(),
 		image:     imagePath,
 	}, nil
 }
@@ -1206,7 +1204,7 @@ func (s *Service) actionProvisioning() actionResult {
 	})
 
 	// check hostname with sshClient
-	wantHostName := infrav1.BareMetalHostNamePrefix + host.Spec.ConsumerRef.Name
+	wantHostName := s.scope.Hostname()
 
 	out := sshClient.GetHostName()
 
@@ -1263,15 +1261,15 @@ func (s *Service) actionProvisioning() actionResult {
 	}
 
 	// we are in correct boot and can start provisioning
-	if failedAction := s.provision(sshClient, host.Spec.ConsumerRef.Name); failedAction != nil {
+	if failedAction := s.provision(sshClient); failedAction != nil {
 		return failedAction
 	}
 
 	host.ClearError()
 	return actionComplete{}
 }
 
-func (s *Service) provision(sshClient sshclient.Client, machineName string) actionResult {
+func (s *Service) provision(sshClient sshclient.Client) actionResult {
 	{
 		out := sshClient.EnsureCloudInit()
 		if err := handleSSHError(out); err != nil {
@@ -1295,7 +1293,7 @@ func (s *Service) provision(sshClient sshclient.Client, machineName string) acti
 		return actionError{err: fmt.Errorf("failed to create no cloud directory: %w", err)}
 	}
 
-	if err := handleSSHError(sshClient.CreateMetaData(infrav1.BareMetalHostNamePrefix + machineName)); err != nil {
+	if err := handleSSHError(sshClient.CreateMetaData(s.scope.Hostname())); err != nil {
 		return actionError{err: fmt.Errorf("failed to create meta data: %w", err)}
 	}
 
@@ -1415,7 +1413,7 @@ func (s *Service) actionEnsureProvisioned() (ar actionResult) {
 		}
 	}()
 	// Check hostname with sshClient
-	wantHostName := infrav1.BareMetalHostNamePrefix + s.scope.HetznerBareMetalHost.Spec.ConsumerRef.Name
+	wantHostName := s.scope.Hostname()
 
 	out := sshClient.GetHostName()
 	if trimLineBreak(out.StdOut) != wantHostName {
@@ -1628,7 +1626,8 @@ func (s *Service) actionProvisioned() actionResult {
 			// Check hostname with sshClient
 			out := sshClient.GetHostName()
 
-			wantHostName := infrav1.BareMetalHostNamePrefix + s.scope.HetznerBareMetalHost.Spec.ConsumerRef.Name
+			wantHostName := s.scope.Hostname()
+
 			if trimLineBreak(out.StdOut) == wantHostName {
 				// Reboot has been successful
 				s.scope.HetznerBareMetalHost.Spec.Status.Rebooted = false

pkg/services/baremetal/host/host_suite_test.go

@@ -23,9 +23,11 @@ import (
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
 	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/klog/v2/textlogger"
+	clusterv1 "sigs.k8s.io/cluster-api/api/v1beta1"
 	fakeclient "sigs.k8s.io/controller-runtime/pkg/client/fake"
 
 	infrav1 "github.com/syself/cluster-api-provider-hetzner/api/v1beta1"
@@ -88,6 +90,8 @@ func newTestService(
 			HetznerCluster: &infrav1.HetznerCluster{
 				Spec: helpers.GetDefaultHetznerClusterSpec(),
 			},
+			// Attention: this doesn't make sense if we test with constant node names
+			Cluster:         &clusterv1.Cluster{ObjectMeta: metav1.ObjectMeta{Name: "cluster"}},
 			OSSSHSecret:     osSSHSecret,
 			RescueSSHSecret: rescueSSHSecret,
 		},