Fix gke master version

cloud/services/container/clusters/reconcile.go

@@ -19,6 +19,7 @@ package clusters
 import (
 	"context"
 	"fmt"
+	"strings"
 
 	"sigs.k8s.io/cluster-api-provider-gcp/cloud/scope"
 	"sigs.k8s.io/cluster-api-provider-gcp/cloud/services/shared"
@@ -262,7 +263,7 @@ func (s *Service) createCluster(ctx context.Context, log *logr.Logger) error {
 		MasterAuthorizedNetworksConfig: convertToSdkMasterAuthorizedNetworksConfig(s.scope.GCPManagedControlPlane.Spec.MasterAuthorizedNetworksConfig),
 	}
 	if s.scope.GCPManagedControlPlane.Spec.ControlPlaneVersion != nil {
-		cluster.InitialClusterVersion = *s.scope.GCPManagedControlPlane.Spec.ControlPlaneVersion
+		cluster.InitialClusterVersion = convertToSdkMasterVersion(*s.scope.GCPManagedControlPlane.Spec.ControlPlaneVersion)
 	}
 	if !s.scope.IsAutopilotCluster() {
 		cluster.NodePools = scope.ConvertToSdkNodePools(nodePools, machinePools, isRegional, cluster.Name)
@@ -333,6 +334,11 @@ func convertToSdkReleaseChannel(channel *infrav1exp.ReleaseChannel) containerpb.
 	}
 }
 
+func convertToSdkMasterVersion(masterVersion string) string {
+	// For example, the master version returned from GCP SDK can be 1.27.2-gke.2100, we want to convert it to 1.27.2
+	return strings.Replace(strings.Split(masterVersion, "-")[0], "v", "", 1)
+}
+
 // convertToSdkMasterAuthorizedNetworksConfig converts the MasterAuthorizedNetworksConfig defined in CRs to the SDK version.
 func convertToSdkMasterAuthorizedNetworksConfig(config *infrav1exp.MasterAuthorizedNetworksConfig) *containerpb.MasterAuthorizedNetworksConfig {
 	// if config is nil, it means that the user wants to disable the feature.
@@ -376,11 +382,12 @@ func (s *Service) checkDiffAndPrepareUpdate(existingCluster *containerpb.Cluster
 	}
 	// Master version
 	if s.scope.GCPManagedControlPlane.Spec.ControlPlaneVersion != nil {
-		desiredMasterVersion := *s.scope.GCPManagedControlPlane.Spec.ControlPlaneVersion
-		if desiredMasterVersion != existingCluster.CurrentMasterVersion {
+		desiredMasterVersion := convertToSdkMasterVersion(*s.scope.GCPManagedControlPlane.Spec.ControlPlaneVersion)
+		existingClusterMasterVersion := convertToSdkMasterVersion(existingCluster.CurrentMasterVersion)
+		if desiredMasterVersion != existingClusterMasterVersion {
 			needUpdate = true
 			clusterUpdate.DesiredMasterVersion = desiredMasterVersion
-			log.V(2).Info("Master version update required", "current", existingCluster.CurrentMasterVersion, "desired", desiredMasterVersion)
+			log.V(2).Info("Master version update required", "current", existingClusterMasterVersion, "desired", desiredMasterVersion)
 		}
 	}