code: func (n *NodeIPTables) syncIPTableRules() error {
  	n.mu.Lock()
  	defer n.mu.Unlock()
  
  	start := time.Now()
  	defer func() {
  		glog.V(4).Infof("syncIPTableRules took %v", time.Since(start))
  	}()
  	glog.V(3).Infof("Syncing openshift iptables rules")
  
  	rules := n.getStaticNodeIPTablesRules()
  	for _, rule := range rules {
  		_, err := n.ipt.EnsureRule(iptables.Prepend, iptables.Table(rule.table), iptables.Chain(rule.chain), rule.args...)
  		if err != nil {
  			return fmt.Errorf("Failed to ensure rule %v exists: %v", rule, err)
  		}
  	}
  	return nil
  }
docs: // syncIPTableRules syncs the cluster network cidr iptables rules.
  // Called from SyncLoop() or firwalld reload()