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WIP: fix for issue 17790 #17791

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92af480
WIP: fix for issue 17790
dezmodue Dec 5, 2025
d708a7f
Fix fmt
dezmodue Dec 5, 2025
76ffed3
Validate that the podIP is Internal
dezmodue Dec 7, 2025
af3a865
Improve tests
dezmodue Dec 8, 2025
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54 changes: 37 additions & 17 deletions dns-controller/pkg/watchers/pod.go
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Original file line number Diff line number Diff line change
Expand Up @@ -142,6 +142,25 @@ func (c *PodController) runWatcher(stopCh <-chan struct{}) {
}
}

// podIPsMatchingNodeInternalIP checks which pod IPs match a NodeInternalIP address on the specified node
func (c *PodController) podIPsMatchingNodeInternalIP(pod *v1.Pod) []string {
ctx := context.TODO()
var internalIPs []string
node, err := c.client.CoreV1().Nodes().Get(ctx, pod.Spec.NodeName, metav1.GetOptions{})
if err != nil {
klog.Warningf("Failed to get node %q: %v", pod.Spec.NodeName, err)
return []string{}
}
for _, podIP := range pod.Status.PodIPs {
for _, addr := range node.Status.Addresses {
if addr.Type == v1.NodeInternalIP && addr.Address == podIP.IP {
internalIPs = append(internalIPs, addr.Address)
}
}
}
return internalIPs
}

// updatePodRecords will apply the records for the specified pod. It returns the key that was set.
func (c *PodController) updatePodRecords(pod *v1.Pod) string {
var records []dns.Record
Expand Down Expand Up @@ -176,27 +195,28 @@ func (c *PodController) updatePodRecords(pod *v1.Pod) string {

specInternal := pod.Annotations[AnnotationNameDNSInternal]
if specInternal != "" {
var aliases []string
if pod.Spec.HostNetwork {
if pod.Spec.NodeName != "" {
aliases = append(aliases, "node/"+pod.Spec.NodeName+"/internal")
}
} else {
klog.V(4).Infof("Pod %q had %s=%s, but was not HostNetwork", pod.Name, AnnotationNameDNSInternal, specInternal)
}

tokens := strings.Split(specInternal, ",")
for _, token := range tokens {
token = strings.TrimSpace(token)

fqdn := dns.EnsureDotSuffix(token)
for _, alias := range aliases {
records = append(records, dns.Record{
RecordType: dns.RecordTypeAlias,
FQDN: fqdn,
Value: alias,
})
if pod.Spec.NodeName != "" && pod.Spec.HostNetwork {
podInternalIPs := c.podIPsMatchingNodeInternalIP(pod)
if len(podInternalIPs) == 0 {
klog.V(4).Infof("Pod %q IPs do not match any NodeInternalIP on node %q", pod.Name, pod.Spec.NodeName)
} else {
for _, token := range tokens {
token = strings.TrimSpace(token)
fqdn := dns.EnsureDotSuffix(token)
for _, podIP := range podInternalIPs {
records = append(records, dns.Record{
RecordType: dns.RecordTypeA,
FQDN: fqdn,
Value: podIP,
})
}
}
}
} else {
klog.V(4).Infof("Pod %q had %s=%s, but was not HostNetwork or NodeName not set", pod.Name, AnnotationNameDNSInternal, specInternal)
}
} else {
klog.V(4).Infof("Pod %q did not have %s label", pod.Name, AnnotationNameDNSInternal)
Expand Down
39 changes: 35 additions & 4 deletions dns-controller/pkg/watchers/pod_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -30,12 +30,32 @@ import (

func TestPodController(t *testing.T) {
ctx := context.Background()

nspec := &corev1.Node{
ObjectMeta: metav1.ObjectMeta{
Name: "my-node",
},
Status: corev1.NodeStatus{
Addresses: []corev1.NodeAddress{
// Internal IPs allocated to the Pod
{Type: corev1.NodeInternalIP, Address: "10.0.0.1"},
{Type: corev1.NodeInternalIP, Address: "10.0.0.2"},
// The following 2 addresses should be ignored, as they are not associated allocated to the Pod
{Type: corev1.NodeInternalIP, Address: "10.0.0.3"},
{Type: corev1.NodeInternalIP, Address: "10.0.0.4"},
// External IPs
{Type: corev1.NodeExternalIP, Address: "2001:db8:0:0:0:ff00:42:8329"},
{Type: corev1.NodeExternalIP, Address: "54.100.0.1"},
},
},
}

pspec := &corev1.Pod{
ObjectMeta: metav1.ObjectMeta{
Name: "somepod",
Namespace: "kube-system",
Annotations: map[string]string{
"dns.alpha.kubernetes.io/internal": "internal.a.foo.com",
"dns.alpha.kubernetes.io/internal": "internal.a.foo.com,internal.b.foo.com",
"dns.alpha.kubernetes.io/external": "a.foo.com",
},
},
Expand All @@ -47,15 +67,23 @@ func TestPodController(t *testing.T) {
PodIP: "10.0.0.1",
PodIPs: []corev1.PodIP{
{IP: "10.0.0.1"},
{IP: "10.0.0.2"},
{IP: "2001:db8:0:0:0:ff00:42:8329"},
{IP: "54.100.0.1"},
},
},
}

client := fake.NewClientset()
pods := client.CoreV1().Pods("kube-system")

_, err := pods.Create(ctx, pspec, metav1.CreateOptions{})
nodes := client.CoreV1().Nodes()
_, err := nodes.Create(ctx, nspec, metav1.CreateOptions{})
if err != nil {
t.Fatalf("unexpected error creating node: %v", err)
}

pods := client.CoreV1().Pods("kube-system")
_, err = pods.Create(ctx, pspec, metav1.CreateOptions{})
if err != nil {
t.Fatalf("unexpected error: %v", err)
}
Expand Down Expand Up @@ -88,7 +116,10 @@ func TestPodController(t *testing.T) {
want := map[string][]dns.Record{
"kube-system/somepod": {
{RecordType: "_alias", FQDN: "a.foo.com.", Value: "node/my-node/external"},
{RecordType: "_alias", FQDN: "internal.a.foo.com.", Value: "node/my-node/internal"},
{RecordType: "A", FQDN: "internal.a.foo.com.", Value: "10.0.0.1"},
{RecordType: "A", FQDN: "internal.a.foo.com.", Value: "10.0.0.2"},
{RecordType: "A", FQDN: "internal.b.foo.com.", Value: "10.0.0.1"},
{RecordType: "A", FQDN: "internal.b.foo.com.", Value: "10.0.0.2"},
},
}
if diff := cmp.Diff(scope.records, want); diff != "" {
Expand Down
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