Implementation for minTTL

build/charts/antrea/conf/antrea-agent.conf

@@ -306,6 +306,11 @@ kubeAPIServerOverride: {{ .Values.kubeAPIServerOverride | quote }}
 # 10.96.0.10:53, [fd00:10:96::a]:53).
 dnsServerOverride: {{ .Values.dnsServerOverride | quote }}
 
+# The fqdnCacheMinTTL helps address the problem of applications caching DNS response IPs beyond the TTL value for the DNS record.
+# It is used to enforce FQDN policy rules, ensuring that resolved IPs are included in datapath rules for as long as the application is caching them.
+# This value should ideally be set to the maximum caching duration across all applications.
+fqdnCacheMinTTL: {{ .Values.fqdnCacheMinTTL }}
+
 # Comma-separated list of Cipher Suites. If omitted, the default Go Cipher Suites will be used.
 # https://golang.org/pkg/crypto/tls/#pkg-constants
 # Note that TLS1.3 Cipher Suites cannot be added to the list. But the apiserver will always

build/charts/antrea/values.yaml

@@ -186,6 +186,10 @@ kubeAPIServerOverride: ""
 # -- Address of DNS server, to override the kube-dns Service. It's used to
 # resolve hostnames in a FQDN policy.
 dnsServerOverride: ""
+# -- The minTTL setting helps address the problem of applications caching DNS response IPs indefinitely.
+# The Cluster administrators should configure this value, ideally setting it to be equal to or greater than the maximum TTL
+# value of the application's DNS cache.
+fqdnCacheMinTTL: 0
 # -- IPv4 CIDR range used for Services. Required when AntreaProxy is disabled.
 serviceCIDR: ""
 # -- IPv6 CIDR range used for Services. Required when AntreaProxy is disabled.

build/yamls/antrea-aks.yml

@@ -4234,6 +4234,11 @@ data:
     # 10.96.0.10:53, [fd00:10:96::a]:53).
     dnsServerOverride: ""
 
+    # The fqdnCacheMinTTL setting helps address the problem of applications caching DNS response IPs beyond the TTL value for the DNS record.
+    # It is used to enforce FQDN policy rules, ensuring that resolved IPs are included in datapath rules for as long as the application is caching them.
+    # This value should ideally be set to the maximum caching duration across all applications.
+    fqdnCacheMinTTL: 0
+
     # Comma-separated list of Cipher Suites. If omitted, the default Go Cipher Suites will be used.
     # https://golang.org/pkg/crypto/tls/#pkg-constants
     # Note that TLS1.3 Cipher Suites cannot be added to the list. But the apiserver will always
@@ -5383,7 +5388,7 @@ spec:
         kubectl.kubernetes.io/default-container: antrea-agent
         # Automatically restart Pods with a RollingUpdate if the ConfigMap changes
         # See https://helm.sh/docs/howto/charts_tips_and_tricks/#automatically-roll-deployments
-        checksum/config: e2d1d8af083c88667ac4c22c87dea63e595b2f4f770190c32afb00c480440fe3
+        checksum/config: e110c8521f19cd9446a44a03bd30688f9dc9925a22e4663865a00ae57eb45321
       labels:
         app: antrea
         component: antrea-agent
@@ -5621,7 +5626,7 @@ spec:
       annotations:
         # Automatically restart Pod if the ConfigMap changes
         # See https://helm.sh/docs/howto/charts_tips_and_tricks/#automatically-roll-deployments
-        checksum/config: e2d1d8af083c88667ac4c22c87dea63e595b2f4f770190c32afb00c480440fe3
+        checksum/config: e110c8521f19cd9446a44a03bd30688f9dc9925a22e4663865a00ae57eb45321
       labels:
         app: antrea
         component: antrea-controller

build/yamls/antrea-eks.yml

@@ -4234,6 +4234,11 @@ data:
     # 10.96.0.10:53, [fd00:10:96::a]:53).
     dnsServerOverride: ""
 
+    # The fqdnCacheMinTTL setting helps address the problem of applications caching DNS response IPs beyond the TTL value for the DNS record.
+    # It is used to enforce FQDN policy rules, ensuring that resolved IPs are included in datapath rules for as long as the application is caching them.
+    # This value should ideally be set to the maximum caching duration across all applications.
+    fqdnCacheMinTTL: 0
+
     # Comma-separated list of Cipher Suites. If omitted, the default Go Cipher Suites will be used.
     # https://golang.org/pkg/crypto/tls/#pkg-constants
     # Note that TLS1.3 Cipher Suites cannot be added to the list. But the apiserver will always
@@ -5383,7 +5388,7 @@ spec:
         kubectl.kubernetes.io/default-container: antrea-agent
         # Automatically restart Pods with a RollingUpdate if the ConfigMap changes
         # See https://helm.sh/docs/howto/charts_tips_and_tricks/#automatically-roll-deployments
-        checksum/config: e2d1d8af083c88667ac4c22c87dea63e595b2f4f770190c32afb00c480440fe3
+        checksum/config: e110c8521f19cd9446a44a03bd30688f9dc9925a22e4663865a00ae57eb45321
       labels:
         app: antrea
         component: antrea-agent
@@ -5622,7 +5627,7 @@ spec:
       annotations:
         # Automatically restart Pod if the ConfigMap changes
         # See https://helm.sh/docs/howto/charts_tips_and_tricks/#automatically-roll-deployments
-        checksum/config: e2d1d8af083c88667ac4c22c87dea63e595b2f4f770190c32afb00c480440fe3
+        checksum/config: e110c8521f19cd9446a44a03bd30688f9dc9925a22e4663865a00ae57eb45321
       labels:
         app: antrea
         component: antrea-controller

build/yamls/antrea-gke.yml

@@ -4234,6 +4234,11 @@ data:
     # 10.96.0.10:53, [fd00:10:96::a]:53).
     dnsServerOverride: ""
 
+    # The fqdnCacheMinTTL setting helps address the problem of applications caching DNS response IPs beyond the TTL value for the DNS record.
+    # It is used to enforce FQDN policy rules, ensuring that resolved IPs are included in datapath rules for as long as the application is caching them.
+    # This value should ideally be set to the maximum caching duration across all applications.
+    fqdnCacheMinTTL: 0
+
     # Comma-separated list of Cipher Suites. If omitted, the default Go Cipher Suites will be used.
     # https://golang.org/pkg/crypto/tls/#pkg-constants
     # Note that TLS1.3 Cipher Suites cannot be added to the list. But the apiserver will always
@@ -5383,7 +5388,7 @@ spec:
         kubectl.kubernetes.io/default-container: antrea-agent
         # Automatically restart Pods with a RollingUpdate if the ConfigMap changes
         # See https://helm.sh/docs/howto/charts_tips_and_tricks/#automatically-roll-deployments
-        checksum/config: 7e42a403d388e2ed556d9b41f4af83917eadd0863d4e2bef67353f5adb2ef6c3
+        checksum/config: 46818c48f6a155057238465531d114fac58b552fa27d643e04e6272e45a22671
       labels:
         app: antrea
         component: antrea-agent
@@ -5619,7 +5624,7 @@ spec:
       annotations:
         # Automatically restart Pod if the ConfigMap changes
         # See https://helm.sh/docs/howto/charts_tips_and_tricks/#automatically-roll-deployments
-        checksum/config: 7e42a403d388e2ed556d9b41f4af83917eadd0863d4e2bef67353f5adb2ef6c3
+        checksum/config: 46818c48f6a155057238465531d114fac58b552fa27d643e04e6272e45a22671
       labels:
         app: antrea
         component: antrea-controller

build/yamls/antrea-ipsec.yml

@@ -4247,6 +4247,11 @@ data:
     # 10.96.0.10:53, [fd00:10:96::a]:53).
     dnsServerOverride: ""
 
+    # The fqdnCacheMinTTL setting helps address the problem of applications caching DNS response IPs beyond the TTL value for the DNS record.
+    # It is used to enforce FQDN policy rules, ensuring that resolved IPs are included in datapath rules for as long as the application is caching them.
+    # This value should ideally be set to the maximum caching duration across all applications.
+    fqdnCacheMinTTL: 0
+
     # Comma-separated list of Cipher Suites. If omitted, the default Go Cipher Suites will be used.
     # https://golang.org/pkg/crypto/tls/#pkg-constants
     # Note that TLS1.3 Cipher Suites cannot be added to the list. But the apiserver will always
@@ -5396,7 +5401,7 @@ spec:
         kubectl.kubernetes.io/default-container: antrea-agent
         # Automatically restart Pods with a RollingUpdate if the ConfigMap changes
         # See https://helm.sh/docs/howto/charts_tips_and_tricks/#automatically-roll-deployments
-        checksum/config: 7d8b0a065c3db85e34e127fdf38b820b32712657900e3f8fe2703d4310c40632
+        checksum/config: 833415719521cc942d7007330bd1a2a87b200055e35851cdbf4851e68ae41605
         checksum/ipsec-secret: d0eb9c52d0cd4311b6d252a951126bf9bea27ec05590bed8a394f0f792dcb2a4
       labels:
         app: antrea
@@ -5678,7 +5683,7 @@ spec:
       annotations:
         # Automatically restart Pod if the ConfigMap changes
         # See https://helm.sh/docs/howto/charts_tips_and_tricks/#automatically-roll-deployments
-        checksum/config: 7d8b0a065c3db85e34e127fdf38b820b32712657900e3f8fe2703d4310c40632
+        checksum/config: 833415719521cc942d7007330bd1a2a87b200055e35851cdbf4851e68ae41605
       labels:
         app: antrea
         component: antrea-controller

build/yamls/antrea.yml

@@ -4234,6 +4234,11 @@ data:
     # 10.96.0.10:53, [fd00:10:96::a]:53).
     dnsServerOverride: ""
 
+    # The fqdnCacheMinTTL setting helps address the problem of applications caching DNS response IPs beyond the TTL value for the DNS record.
+    # It is used to enforce FQDN policy rules, ensuring that resolved IPs are included in datapath rules for as long as the application is caching them.
+    # This value should ideally be set to the maximum caching duration across all applications.
+    fqdnCacheMinTTL: 0
+
     # Comma-separated list of Cipher Suites. If omitted, the default Go Cipher Suites will be used.
     # https://golang.org/pkg/crypto/tls/#pkg-constants
     # Note that TLS1.3 Cipher Suites cannot be added to the list. But the apiserver will always
@@ -5383,7 +5388,7 @@ spec:
         kubectl.kubernetes.io/default-container: antrea-agent
         # Automatically restart Pods with a RollingUpdate if the ConfigMap changes
         # See https://helm.sh/docs/howto/charts_tips_and_tricks/#automatically-roll-deployments
-        checksum/config: 2b4d82bcb825d50926115bad2125097f85aed424bfc49147444314cad8b7826a
+        checksum/config: 6fd8efc7007f902f7d846353d9386224d8abadd1d8694d2e5702d8328804c330
       labels:
         app: antrea
         component: antrea-agent
@@ -5619,7 +5624,7 @@ spec:
       annotations:
         # Automatically restart Pod if the ConfigMap changes
         # See https://helm.sh/docs/howto/charts_tips_and_tricks/#automatically-roll-deployments
-        checksum/config: 2b4d82bcb825d50926115bad2125097f85aed424bfc49147444314cad8b7826a
+        checksum/config: 6fd8efc7007f902f7d846353d9386224d8abadd1d8694d2e5702d8328804c330
       labels:
         app: antrea
         component: antrea-controller

cmd/antrea-agent/agent.go

@@ -528,6 +528,7 @@ func run(o *Options) error {
 		nodeConfig,
 		podNetworkWait,
 		l7Reconciler,
+		uint32(o.config.FqdnCacheMinTTL),
 	)
 	if err != nil {
 		return fmt.Errorf("error creating new NetworkPolicy controller: %v", err)

cmd/antrea-agent/options.go

@@ -155,6 +155,11 @@ func (o *Options) validate(args []string) error {
 		return fmt.Errorf("nodeType %s requires feature gate ExternalNode to be enabled", o.config.NodeType)
 	}
 
+	// validate FqdnCacheMinTTL
+	if o.config.FqdnCacheMinTTL < 0 {
+		return fmt.Errorf("fqdnCacheMinTTL must be greater than or equal to 0")
+	}
+
 	if o.config.NodeType == config.ExternalNode.String() {
 		o.nodeType = config.ExternalNode
 		return o.validateExternalNodeOptions()

pkg/agent/controller/networkpolicy/fqdn.go

@@ -127,6 +127,7 @@ type fqdnController struct {
 	ofClient openflow.Client
 	// dnsServerAddr stores the coreDNS server address, or the user provided DNS server address.
 	dnsServerAddr string
+	minTTL        uint32
 
 	// dirtyRuleHandler is a callback that is run upon finding a rule out-of-sync.
 	dirtyRuleHandler func(string)
@@ -160,7 +161,7 @@ type fqdnController struct {
 	clock clock.Clock
 }
 
-func newFQDNController(client openflow.Client, allocator *idAllocator, dnsServerOverride string, dirtyRuleHandler func(string), v4Enabled, v6Enabled bool, gwPort uint32, clock clock.WithTicker) (*fqdnController, error) {
+func newFQDNController(client openflow.Client, allocator *idAllocator, dnsServerOverride string, dirtyRuleHandler func(string), v4Enabled, v6Enabled bool, gwPort uint32, clock clock.WithTicker, fqdnCacheMinTTL uint32) (*fqdnController, error) {
 	controller := &fqdnController{
 		ofClient:         client,
 		dirtyRuleHandler: dirtyRuleHandler,
@@ -182,6 +183,7 @@ func newFQDNController(client openflow.Client, allocator *idAllocator, dnsServer
 		ipv6Enabled:            v6Enabled,
 		gwPort:                 gwPort,
 		clock:                  clock,
+		minTTL:                 fqdnCacheMinTTL,
 	}
 	if controller.ofClient != nil {
 		if err := controller.ofClient.NewDNSPacketInConjunction(dnsInterceptRuleID); err != nil {
@@ -643,15 +645,15 @@ func (f *fqdnController) parseDNSResponse(msg *dns.Msg) (string, map[string]ipWi
 			if f.ipv4Enabled {
 				responseIPs[r.A.String()] = ipWithExpiration{
 					ip:             r.A,
-					expirationTime: currentTime.Add(time.Duration(r.Header().Ttl) * time.Second),
+					expirationTime: currentTime.Add(time.Duration(max(f.minTTL, r.Header().Ttl)) * time.Second),
 				}
 
 			}
 		case *dns.AAAA:
 			if f.ipv6Enabled {
 				responseIPs[r.AAAA.String()] = ipWithExpiration{
 					ip:             r.AAAA,
-					expirationTime: currentTime.Add(time.Duration(r.Header().Ttl) * time.Second),
+					expirationTime: currentTime.Add(time.Duration(max(f.minTTL, r.Header().Ttl)) * time.Second),
 				}
 			}
 		}