code: func managerNode(nodeID string, availability api.NodeSpec_Availability, vxlanPort uint32) *api.Node {
  	return &api.Node{
  		ID: nodeID,
  		Certificate: api.Certificate{
  			CN:   nodeID,
  			Role: api.NodeRoleManager,
  			Status: api.IssuanceStatus{
  				State: api.IssuanceStateIssued,
  			},
  		},
  		Spec: api.NodeSpec{
  			DesiredRole:  api.NodeRoleManager,
  			Membership:   api.NodeMembershipAccepted,
  			Availability: availability,
  		},
  		VXLANUDPPort: vxlanPort,
  	}
  }
docs: // managerNode creates a new node with NodeRoleManager role.