func (wr *Wrangler) checkMasterElect(ti *topo.TabletInfo) error {
	// Check the master-elect is fit for duty - call out for hardware checks.
	// if the server was already serving live traffic, it's probably good
	if ti.IsServingType() {
		return nil
	}
	return wr.ExecuteOptionalTabletInfoHook(ti, hook.NewSimpleHook("preflight_serving_type"))
}