ci: add an IPv6-only kind e2e job [DO NOT MERGE — signal only]

cmd/atenet/internal/router/xds.go

@@ -1105,6 +1105,27 @@ func (x *XdsServer) buildTracing() *hcmv3.HttpConnectionManager_Tracing {
 	}
 }
 
+// dualStackAdditionalAddresses returns the IPv6 half of a dual-stack ingress
+// listener, to pair with a primary 0.0.0.0 socket on the same port. Ipv4Compat
+// stays false: clearing IPV6_V6ONLY would collide with that primary.
+func dualStackAdditionalAddresses(port uint32) []*listenerv3.AdditionalAddress {
+	return []*listenerv3.AdditionalAddress{
+		{
+			Address: &corev3.Address{
+				Address: &corev3.Address_SocketAddress{
+					SocketAddress: &corev3.SocketAddress{
+						Address:    "::",
+						Ipv4Compat: false,
+						PortSpecifier: &corev3.SocketAddress_PortValue{
+							PortValue: port,
+						},
+					},
+				},
+			},
+		},
+	}
+}
+
 func (x *XdsServer) buildListener() *listenerv3.Listener {
 	hcm := x.buildHcm("ingress_http", true)
 
@@ -1120,6 +1141,7 @@ func (x *XdsServer) buildListener() *listenerv3.Listener {
 				},
 			},
 		},
+		AdditionalAddresses: dualStackAdditionalAddresses(uint32(x.ingressPort)),
 		FilterChains: []*listenerv3.FilterChain{
 			{
 				Filters: []*listenerv3.Filter{
@@ -1179,6 +1201,7 @@ func (x *XdsServer) buildHttpsListener() *listenerv3.Listener {
 				},
 			},
 		},
+		AdditionalAddresses: dualStackAdditionalAddresses(uint32(x.httpsPort)),
 		FilterChains: []*listenerv3.FilterChain{
 			{
 				Filters: []*listenerv3.Filter{

cmd/atenet/internal/router/xds_test.go

@@ -158,6 +158,22 @@ func TestXdsServer_UpdateSnapshot(t *testing.T) {
 		if sa.GetAddress() != "0.0.0.0" {
 			t.Errorf("Expected address '0.0.0.0', got %s", sa.GetAddress())
 		}
+
+		addrs := l.GetAdditionalAddresses()
+		if len(addrs) == 0 {
+			t.Fatalf("Expected an additional address on %s, got none", IngressHTTPListener)
+		}
+
+		asa := addrs[0].GetAddress().GetSocketAddress()
+		if asa.GetAddress() != "::" {
+			t.Errorf("Expected additional address '::', got %s", asa.GetAddress())
+		}
+		if asa.GetIpv4Compat() {
+			t.Errorf("Expected additional address Ipv4Compat to be false")
+		}
+		if asa.GetPortValue() != 8081 {
+			t.Errorf("Expected additional port 8081, got %d", asa.GetPortValue())
+		}
 	}
 }
 
@@ -196,6 +212,25 @@ func TestXdsServer_UpdateSnapshot_WithHttps(t *testing.T) {
 		if sa.GetPortValue() != 8443 {
 			t.Errorf("Expected port 8443, got %d", sa.GetPortValue())
 		}
+		if sa.GetAddress() != "0.0.0.0" {
+			t.Errorf("Expected address '0.0.0.0', got %s", sa.GetAddress())
+		}
+
+		addrs := l.GetAdditionalAddresses()
+		if len(addrs) == 0 {
+			t.Fatalf("Expected an additional address on %s, got none", IngressHTTPSListener)
+		}
+
+		asa := addrs[0].GetAddress().GetSocketAddress()
+		if asa.GetAddress() != "::" {
+			t.Errorf("Expected additional address '::', got %s", asa.GetAddress())
+		}
+		if asa.GetIpv4Compat() {
+			t.Errorf("Expected additional address Ipv4Compat to be false")
+		}
+		if asa.GetPortValue() != 8443 {
+			t.Errorf("Expected additional port 8443, got %d", asa.GetPortValue())
+		}
 
 		// Verify the TLS config references the serving cert via SDS rather
 		// than embedding it: inline filename DataSources are read only once

hack/create-kind-cluster.sh

@@ -21,6 +21,7 @@ KIND_CLUSTER_NAME="${KIND_CLUSTER_NAME:-kind}"
 KUBECTL_CONTEXT="kind-${KIND_CLUSTER_NAME}"
 reg_name="kind-registry"
 reg_port="${KIND_REGISTRY_PORT:-5001}"
+IPV6_DNS_UPSTREAM="${IPV6_DNS_UPSTREAM:-2001:4860:4860::8888 2001:4860:4860::8844}"
 
 if [[ $# -gt 0 ]]; then
   case "$1" in
@@ -31,6 +32,8 @@ if [[ $# -gt 0 ]]; then
       echo "Configured through the environment:"
       echo "  KIND_CLUSTER_NAME  Name of the cluster to create (default: kind)."
       echo "  IP_FAMILY          Address families for pods and Services: ipv4, ipv6 or dual (default: ipv4)."
+      echo "  IPV6_DNS_UPSTREAM  Space-separated IPv6 resolvers CoreDNS forwards to when IP_FAMILY=ipv6"
+      echo "                     (default: Google Public DNS). Override where those are unreachable."
       exit 0
       ;;
   esac
@@ -196,6 +199,67 @@ if [ "$(docker inspect -f='{{json .NetworkSettings.Networks.kind}}' "${reg_name}
   docker network connect "kind" "${reg_name}"
 fi
 
+# 4.5. Give CoreDNS an IPv6 forwarder and a registry entry (ipv6 only)
+#
+# CoreDNS runs dnsPolicy: Default, so it inherits the node's Docker-generated
+# /etc/resolv.conf, which always names an IPv4 resolver. Pods here have no IPv4
+# address, so without this every external lookup SERVFAILs and anything that
+# fetches at runtime -- atelet pulling the gVisor tarball, for one -- never
+# starts. Step 3 wired the registry into containerd on the *node*, which does
+# not help a pod: atelet pulls actor images from its own netns, where
+# "kind-registry" NXDOMAINs. Two Corefile clauses fix both.
+if [[ "${IP_FAMILY}" == "ipv6" ]]; then
+  echo "Repointing CoreDNS at an IPv6 resolver and teaching it '${reg_name}'..."
+  reg_v6="$(docker inspect "${reg_name}" \
+    --format '{{.NetworkSettings.Networks.kind.GlobalIPv6Address}}')"
+  if [[ -z "${reg_v6}" ]]; then
+    echo "error: '${reg_name}' has no IPv6 address on the 'kind' network" >&2
+    exit 1
+  fi
+
+  corefile="$(kubectl --context="${KUBECTL_CONTEXT}" -n kube-system get cm coredns \
+    -o jsonpath='{.data.Corefile}')"
+  # fallthrough is load-bearing: without it every name that is not the registry
+  # NXDOMAINs, trading one outage for a worse one. Both sides are left unquoted
+  # -- bash 3.2 would splice the quotes in literally.
+  search="forward . /etc/resolv.conf"
+  replace="hosts {
+       ${reg_v6} ${reg_name}
+       fallthrough
+    }
+    forward . ${IPV6_DNS_UPSTREAM}"
+  patched="${corefile/$search/$replace}"
+  if [[ "${patched}" == "${corefile}" ]]; then
+    echo "error: '${search}' not found in the CoreDNS Corefile" >&2
+    echo "       a silent no-op here is the whole failure mode; inspect it by hand" >&2
+    exit 1
+  fi
+
+  # A YAML patch file avoids escaping the Corefile's newlines into JSON.
+  { printf 'data:\n  Corefile: |\n'; printf '%s\n' "${patched}" | sed 's/^/    /'; } \
+    > "${ROOT}/bin/coredns-patch.yaml"
+  kubectl --context="${KUBECTL_CONTEXT}" -n kube-system patch cm coredns \
+    --type=merge --patch-file "${ROOT}/bin/coredns-patch.yaml"
+  kubectl --context="${KUBECTL_CONTEXT}" -n kube-system rollout restart deploy/coredns
+  kubectl --context="${KUBECTL_CONTEXT}" -n kube-system rollout status deploy/coredns \
+    --timeout=120s
+
+  # Probe from a pod, never from the node: the node is dual-stack and resolves
+  # both names either way, so a node-side check proves nothing. The registry leg
+  # fetches rather than resolves, because the hosts entry above is AAAA-only and
+  # `nslookup kind-registry` fails on its A query even though every real client
+  # (getaddrinfo, and so containerd and atelet) is satisfied by the AAAA.
+  echo "Verifying DNS from a pod..."
+  if ! kubectl --context="${KUBECTL_CONTEXT}" run "coredns-probe-$$" \
+    --rm --attach --quiet --restart=Never --image=busybox:1.36 --command -- \
+    sh -c "nslookup storage.googleapis.com >/dev/null &&
+           wget -q -T10 -O/dev/null http://${reg_name}:5000/v2/"; then
+    echo "error: a pod cannot resolve an external name and reach '${reg_name}'" >&2
+    echo "       IPV6_DNS_UPSTREAM is '${IPV6_DNS_UPSTREAM}'; set it to a reachable resolver" >&2
+    exit 1
+  fi
+fi
+
 # 5. Document the local registry in kube-public ConfigMap
 echo "Documenting local registry in cluster..."
 cat <<EOF | kubectl --context="${KUBECTL_CONTEXT}" apply -f -

manifests/ate-install/atenet-egress.yaml

@@ -37,12 +37,13 @@ data:
   envoy.yaml: |
     admin:
       address:
-        socket_address: { address: 0.0.0.0, port_value: 15000 }
+        # ipv4_compat: the drainer dials this on IPv4 loopback (--envoy-admin-address, below).
+        socket_address: { address: "::", ipv4_compat: true, port_value: 15000 }
     static_resources:
       listeners:
       - name: egress
         address:
-          socket_address: { address: 0.0.0.0, port_value: 443 }
+          socket_address: { address: "::", ipv4_compat: true, port_value: 443 }
         filter_chains:
         # Named so ext_proc can read it back as xds.filter_chain_name. Must
         # match EgressFilterChainName in
@@ -379,6 +380,8 @@ metadata:
   namespace: ate-system
 spec:
   type: ClusterIP
+  # Prefer, not Require: Require fails Service creation on a single-stack cluster.
+  ipFamilyPolicy: PreferDualStack
   selector:
     app: atenet-egress
   ports:

manifests/ate-install/atenet-router.yaml

@@ -86,7 +86,10 @@ data:
     admin:
       address:
         socket_address:
-          address: 0.0.0.0
+          # ipv4_compat clears IPV6_V6ONLY, so this one socket serves both
+          # families; dataplane.go probes /ready over the IPv4 loopback.
+          address: "::"
+          ipv4_compat: true
           port_value: 9901
 
     node:
@@ -354,6 +357,8 @@ metadata:
   namespace: ate-system
 spec:
   type: ClusterIP
+  # Prefer, not Require: Require fails Service creation on a single-stack cluster.
+  ipFamilyPolicy: PreferDualStack
   selector:
     app: atenet-router
   ports: