Get cluster health before an update

As per redpanda-data#3023 the cluster should
be healthy before starting put node in maintanance mode and after POD is
restarted.

src/go/k8s/pkg/admin/admin.go

@@ -97,6 +97,8 @@ type AdminAPIClient interface {
 
 	EnableMaintenanceMode(ctx context.Context, node int) error
 	DisableMaintenanceMode(ctx context.Context, node int) error
+
+	GetHealthOverview(ctx context.Context) (admin.ClusterHealthOverview, error)
 }
 
 var _ AdminAPIClient = &admin.AdminAPI{}

src/go/k8s/pkg/resources/statefulset_update.go

@@ -82,6 +82,10 @@ func (r *StatefulSetResource) runUpdate(
 		return err
 	}
 
+	if err = r.isClusterHealthy(ctx); err != nil {
+		return err
+	}
+
 	if err = r.rollingUpdate(ctx, &modified.Spec.Template); err != nil {
 		return err
 	}
@@ -94,6 +98,32 @@ func (r *StatefulSetResource) runUpdate(
 	return nil
 }
 
+func (r *StatefulSetResource) isClusterHealthy(ctx context.Context) error {
+	adminAPIClient, err := r.getAdminAPIClient(ctx)
+	if err != nil {
+		return fmt.Errorf("creating admin API client: %w", err)
+	}
+
+	health, err := adminAPIClient.GetHealthOverview(ctx)
+	if err != nil {
+		return fmt.Errorf("getting cluster health overview: %w", err)
+	}
+
+	restarting := "not restarting"
+	if r.pandaCluster.Status.IsRestarting() {
+		restarting = "restarting"
+	}
+
+	if !health.IsHealthy {
+		return &RequeueAfterError{
+			RequeueAfter: RequeueDuration,
+			Msg:          fmt.Sprintf("wait for cluster to become healthy (cluster %s)", restarting),
+		}
+	}
+
+	return nil
+}
+
 func (r *StatefulSetResource) rollingUpdate(
 	ctx context.Context, template *corev1.PodTemplateSpec,
 ) error {