add feature gate ClusterInit (#766)

Signed-off-by: Di Xu <stephenhsu90@gmail.com>

clusters/v1beta1/types.go

@@ -54,6 +54,12 @@ const (
 const (
 	// ClusterReady means cluster is ready.
 	ClusterReady = "Ready"
+
+	// ClusterInit indicates whether the cluster has been initialised (optional) after joining.
+	// In some cases, some extra customized operations are needed to provide some add-on features, such as
+	// multi-cluster networking, etc.
+	// With this feature, Clusternet provides a hook to help perform such operations.
+	ClusterInit = "ClusterInit"
 )
 
 // ClusterRegistrationRequestSpec defines the desired state of ClusterRegistrationRequest
@@ -181,6 +187,7 @@ type ClusterRegistrationRequestList struct {
 }
 
 // ManagedClusterSpec defines the desired state of ManagedCluster
+// +kubebuilder:validation:XValidation:rule="!has(oldSelf.clusterInitSubName) || has(self.clusterInitSubName)", message="clusterInitSubName is required once set"
 type ManagedClusterSpec struct {
 	// ClusterID, a Random (Version 4) UUID, is a unique value in time and space value representing for child cluster.
 	// It is typically generated by the clusternet agent on the successful creation of a "clusternet-agent" Lease
@@ -199,6 +206,17 @@ type ManagedClusterSpec struct {
 	// +kubebuilder:validation:Type=string
 	ClusterType ClusterType `json:"clusterType,omitempty"`
 
+	// ClusterInitBaseName denotes the name of a Base used for initialization.
+	// Also a taint "clusters.clusternet.io/initialization:NoSchedule" will be added during the operation and removed
+	// after successful initialization.
+	// If this cluster has got an annotation "clusters.clusternet.io/skip-cluster-init", this field will be empty.
+	// Normally this field is fully managed by clusternet-controller-manager and immutable.
+	//
+	// +kubebuilder:validation:Optional
+	// +kubebuilder:validation:XValidation:rule="self == oldSelf",message="clusterInitBaseName is immutable"
+	// +kubebuilder:validation:MaxLength=512
+	ClusterInitBaseName *string `json:"clusterInitBaseName"`
+
 	// SyncMode decides how to sync resources from parent cluster to child cluster.
 	//
 	// +required