kube-proxy ensure KUBE-MARK-DROP exist but not modify their rules

Author: Lion-Wei

pkg/proxy/iptables/proxier.go

@@ -399,6 +399,13 @@ var iptablesJumpChains = []iptablesJumpChain{
 	{utiliptables.TableNAT, kubePostroutingChain, utiliptables.ChainPostrouting, "kubernetes postrouting rules", nil},
 }
 
+var iptablesEnsureChains = []struct {
+	table utiliptables.Table
+	chain utiliptables.Chain
+}{
+	{utiliptables.TableNAT, KubeMarkDropChain},
+}
+
 var iptablesCleanupOnlyChains = []iptablesJumpChain{}
 
 // CleanupLeftovers removes all iptables rules and chains created by the Proxier
@@ -868,6 +875,14 @@ func (proxier *Proxier) syncProxyRules() {
 		}
 	}
 
+	// ensure KUBE-MARK-DROP chain exist but do not change any rules
+	for _, ch := range iptablesEnsureChains {
+		if _, err := proxier.iptables.EnsureChain(ch.table, ch.chain); err != nil {
+			klog.Errorf("Failed to ensure that %s chain %s exists: %v", ch.table, ch.chain, err)
+			return
+		}
+	}
+
 	//
 	// Below this point we will not return until we try to write the iptables rules.
 	//

pkg/proxy/ipvs/proxier.go

@@ -117,10 +117,16 @@ var iptablesChains = []struct {
 	{utiliptables.TableNAT, KubeNodePortChain},
 	{utiliptables.TableNAT, KubeLoadBalancerChain},
 	{utiliptables.TableNAT, KubeMarkMasqChain},
-	{utiliptables.TableNAT, KubeMarkDropChain},
 	{utiliptables.TableFilter, KubeForwardChain},
 }
 
+var iptablesEnsureChains = []struct {
+	table utiliptables.Table
+	chain utiliptables.Chain
+}{
+	{utiliptables.TableNAT, KubeMarkDropChain},
+}
+
 var iptablesCleanupChains = []struct {
 	table utiliptables.Table
 	chain utiliptables.Chain
@@ -1858,6 +1864,14 @@ func (proxier *Proxier) createAndLinkeKubeChain() {
 	existingFilterChains := proxier.getExistingChains(proxier.filterChainsData, utiliptables.TableFilter)
 	existingNATChains := proxier.getExistingChains(proxier.iptablesData, utiliptables.TableNAT)
 
+	// ensure KUBE-MARK-DROP chain exist but do not change any rules
+	for _, ch := range iptablesEnsureChains {
+		if _, err := proxier.iptables.EnsureChain(ch.table, ch.chain); err != nil {
+			klog.Errorf("Failed to ensure that %s chain %s exists: %v", ch.table, ch.chain, err)
+			return
+		}
+	}
+
 	// Make sure we keep stats for the top-level chains
 	for _, ch := range iptablesChains {
 		if _, err := proxier.iptables.EnsureChain(ch.table, ch.chain); err != nil {