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e2e conntrack tests
deflake current e2e test "should be able to preserve UDP traffic when server pod cycles for a NodePort service" and reorganize the code in the e2e framework Signed-off-by: Antonio Ojea <antonio.ojea.garcia@gmail.com>
This commit is contained in:
Antonio Ojea
parent
653eb230f2
commit
27d32661c2
@ -8,6 +8,7 @@ load(
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go_library(
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name = "go_default_library",
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srcs = [
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"conntrack.go",
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"dns.go",
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"dns_common.go",
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"dns_configmap.go",
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246
test/e2e/network/conntrack.go
Normal file
246
test/e2e/network/conntrack.go
Normal file
@ -0,0 +1,246 @@
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/*
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Copyright 2020 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package network
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import (
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"fmt"
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"strings"
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"time"
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"github.com/onsi/ginkgo"
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v1 "k8s.io/api/core/v1"
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metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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"k8s.io/apimachinery/pkg/util/intstr"
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clientset "k8s.io/client-go/kubernetes"
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"k8s.io/kubernetes/test/e2e/framework"
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e2enode "k8s.io/kubernetes/test/e2e/framework/node"
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e2epod "k8s.io/kubernetes/test/e2e/framework/pod"
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e2eservice "k8s.io/kubernetes/test/e2e/framework/service"
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e2eskipper "k8s.io/kubernetes/test/e2e/framework/skipper"
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)
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const (
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serviceName = "svc-udp"
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podClient = "pod-client"
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podBackend1 = "pod-server-1"
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podBackend2 = "pod-server-2"
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srcPort = 12345
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)
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// Linux NAT uses conntrack to perform NAT, everytime a new
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// flow is seen, a connection is created in the conntrack table, and it
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// is being used by the NAT module.
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// Each entry in the conntrack table has associated a timeout, that removes
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// the connection once it expires.
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// UDP is a connectionless protocol, so the conntrack module tracking functions
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// are not very advanced.
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// It uses a short timeout (30 sec by default) that is renewed if there are new flows
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// matching the connection. Otherwise it expires the entry.
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// This behaviour can cause issues in Kubernetes when one entry on the conntrack table
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// is never expired because the sender does not stop sending traffic, but the pods or
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// endpoints were deleted, blackholing the traffic
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// In order to mitigate this problem, Kubernetes delete the stale entries:
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// - when an endpoint is removed
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// - when a service goes from no endpoints to new endpoint
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// Ref: https://api.semanticscholar.org/CorpusID:198903401
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// Boye, Magnus. “Netfilter Connection Tracking and NAT Implementation.” (2012).
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var _ = SIGDescribe("Conntrack", func() {
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fr := framework.NewDefaultFramework("conntrack")
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type nodeInfo struct {
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name string
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nodeIP string
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}
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var (
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cs clientset.Interface
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ns string
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clientNodeInfo, serverNodeInfo nodeInfo
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)
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ginkgo.BeforeEach(func() {
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cs = fr.ClientSet
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ns = fr.Namespace.Name
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nodes, err := e2enode.GetBoundedReadySchedulableNodes(cs, 2)
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framework.ExpectNoError(err)
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if len(nodes.Items) < 2 {
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e2eskipper.Skipf(
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"Test requires >= 2 Ready nodes, but there are only %v nodes",
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len(nodes.Items))
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}
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ips := e2enode.CollectAddresses(nodes, v1.NodeInternalIP)
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clientNodeInfo = nodeInfo{
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name: nodes.Items[0].Name,
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nodeIP: ips[0],
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}
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serverNodeInfo = nodeInfo{
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name: nodes.Items[1].Name,
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nodeIP: ips[1],
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}
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})
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ginkgo.It("should be able to preserve UDP traffic when server pod cycles for a NodePort service", func() {
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// Create a NodePort service
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udpJig := e2eservice.NewTestJig(cs, ns, serviceName)
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ginkgo.By("creating a UDP service " + serviceName + " with type=NodePort in " + ns)
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udpService, err := udpJig.CreateUDPService(func(svc *v1.Service) {
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svc.Spec.Type = v1.ServiceTypeNodePort
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svc.Spec.Ports = []v1.ServicePort{
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{Port: 80, Name: "udp", Protocol: v1.ProtocolUDP, TargetPort: intstr.FromInt(80)},
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}
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})
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framework.ExpectNoError(err)
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// Create a pod in one node to create the UDP traffic against the NodePort service every 5 seconds
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ginkgo.By("creating a client pod for probing the service " + serviceName)
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clientPod := newAgnhostPod(podClient, "")
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clientPod.Spec.NodeName = clientNodeInfo.name
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cmd := fmt.Sprintf(`date; for i in $(seq 1 300); do echo "$(date) Try: ${i}"; echo hostname | nc -u -w 5 -p %d %s %d; echo; done`, srcPort, serverNodeInfo.nodeIP, udpService.Spec.Ports[0].NodePort)
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clientPod.Spec.Containers[0].Command = []string{"/bin/sh", "-c", cmd}
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clientPod.Spec.Containers[0].Name = podClient
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fr.PodClient().CreateSync(clientPod)
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// Read the client pod logs
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logs, err := e2epod.GetPodLogs(cs, ns, podClient, podClient)
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framework.ExpectNoError(err)
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framework.Logf("Pod client logs: %s", logs)
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// Add a backend pod to the service in the other node
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ginkgo.By("creating a backend pod " + podBackend1 + " for the service " + serviceName)
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serverPod1 := newAgnhostPod(podBackend1, "netexec", fmt.Sprintf("--udp-port=%d", 80))
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serverPod1.Labels = udpJig.Labels
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serverPod1.Spec.NodeName = serverNodeInfo.name
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fr.PodClient().CreateSync(serverPod1)
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// Waiting for service to expose endpoint.
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err = validateEndpointsPorts(cs, ns, serviceName, portsByPodName{podBackend1: {80}})
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framework.ExpectNoError(err, "failed to validate endpoints for service %s in namespace: %s", serviceName, ns)
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// Check that the pod receives the traffic
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// UDP conntrack entries timeout is 30 sec by default
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ginkgo.By("checking client pod connected to the backend 1 on Node IP " + serverNodeInfo.nodeIP)
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time.Sleep(30 * time.Second)
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logs, err = e2epod.GetPodLogs(cs, ns, podClient, podClient)
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framework.ExpectNoError(err)
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framework.Logf("Pod client logs: %s", logs)
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if !strings.Contains(string(logs), podBackend1) {
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framework.Failf("Failed to connecto to backend 1")
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}
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// Create a second pod
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ginkgo.By("creating a second backend pod " + podBackend2 + " for the service " + serviceName)
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serverPod2 := newAgnhostPod(podBackend2, "netexec", fmt.Sprintf("--udp-port=%d", 80))
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serverPod2.Labels = udpJig.Labels
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serverPod2.Spec.NodeName = serverNodeInfo.name
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fr.PodClient().CreateSync(serverPod2)
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// and delete the first pod
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framework.Logf("Cleaning up %s pod", podBackend1)
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fr.PodClient().DeleteSync(podBackend1, metav1.DeleteOptions{}, framework.DefaultPodDeletionTimeout)
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// Check that the second pod keeps receiving traffic
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// UDP conntrack entries timeout is 30 sec by default
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ginkgo.By("checking client pod connected to the backend 2 on Node IP " + serverNodeInfo.nodeIP)
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time.Sleep(30 * time.Second)
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logs, err = e2epod.GetPodLogs(cs, ns, podClient, podClient)
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framework.ExpectNoError(err)
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framework.Logf("Pod client logs: %s", logs)
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if !strings.Contains(string(logs), podBackend2) {
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framework.Failf("Failed to connecto to backend 2")
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}
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})
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ginkgo.It("should be able to preserve UDP traffic when server pod cycles for a ClusterIP service", func() {
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// Create a NodePort service
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udpJig := e2eservice.NewTestJig(cs, ns, serviceName)
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ginkgo.By("creating a UDP service " + serviceName + " with type=ClusterIP in " + ns)
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udpService, err := udpJig.CreateUDPService(func(svc *v1.Service) {
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svc.Spec.Type = v1.ServiceTypeClusterIP
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svc.Spec.Ports = []v1.ServicePort{
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{Port: 80, Name: "udp", Protocol: v1.ProtocolUDP, TargetPort: intstr.FromInt(80)},
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}
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})
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framework.ExpectNoError(err)
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// Create a pod in one node to create the UDP traffic against the NodePort service every 5 seconds
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ginkgo.By("creating a client pod for probing the service " + serviceName)
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clientPod := newAgnhostPod(podClient, "")
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clientPod.Spec.NodeName = clientNodeInfo.name
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cmd := fmt.Sprintf(`date; for i in $(seq 1 300); do echo "$(date) Try: ${i}"; echo hostname | nc -u -w 5 -p %d %s %d; echo; done`, srcPort, udpService.Spec.ClusterIP, udpService.Spec.Ports[0].Port)
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clientPod.Spec.Containers[0].Command = []string{"/bin/sh", "-c", cmd}
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clientPod.Spec.Containers[0].Name = podClient
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fr.PodClient().CreateSync(clientPod)
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// Read the client pod logs
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logs, err := e2epod.GetPodLogs(cs, ns, podClient, podClient)
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framework.ExpectNoError(err)
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framework.Logf("Pod client logs: %s", logs)
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// Add a backend pod to the service in the other node
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ginkgo.By("creating a backend pod " + podBackend1 + " for the service " + serviceName)
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serverPod1 := newAgnhostPod(podBackend1, "netexec", fmt.Sprintf("--udp-port=%d", 80))
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serverPod1.Labels = udpJig.Labels
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serverPod1.Spec.NodeName = serverNodeInfo.name
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fr.PodClient().CreateSync(serverPod1)
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// Waiting for service to expose endpoint.
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err = validateEndpointsPorts(cs, ns, serviceName, portsByPodName{podBackend1: {80}})
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framework.ExpectNoError(err, "failed to validate endpoints for service %s in namespace: %s", serviceName, ns)
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// Check that the pod receives the traffic
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// UDP conntrack entries timeout is 30 sec by default
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ginkgo.By("checking client pod connected to the backend 1 on Node IP " + serverNodeInfo.nodeIP)
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time.Sleep(30 * time.Second)
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logs, err = e2epod.GetPodLogs(cs, ns, podClient, podClient)
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framework.ExpectNoError(err)
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framework.Logf("Pod client logs: %s", logs)
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if !strings.Contains(string(logs), podBackend1) {
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framework.Failf("Failed to connecto to backend 1")
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}
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// Create a second pod
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ginkgo.By("creating a second backend pod " + podBackend2 + " for the service " + serviceName)
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serverPod2 := newAgnhostPod(podBackend2, "netexec", fmt.Sprintf("--udp-port=%d", 80))
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serverPod2.Labels = udpJig.Labels
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serverPod2.Spec.NodeName = serverNodeInfo.name
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fr.PodClient().CreateSync(serverPod2)
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// and delete the first pod
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framework.Logf("Cleaning up %s pod", podBackend1)
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fr.PodClient().DeleteSync(podBackend1, metav1.DeleteOptions{}, framework.DefaultPodDeletionTimeout)
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// Check that the second pod keeps receiving traffic
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// UDP conntrack entries timeout is 30 sec by default
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ginkgo.By("checking client pod connected to the backend 2 on Node IP " + serverNodeInfo.nodeIP)
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time.Sleep(30 * time.Second)
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logs, err = e2epod.GetPodLogs(cs, ns, podClient, podClient)
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framework.ExpectNoError(err)
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framework.Logf("Pod client logs: %s", logs)
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if !strings.Contains(string(logs), podBackend2) {
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framework.Failf("Failed to connecto to backend 2")
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}
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})
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})
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@ -518,123 +518,6 @@ func pokeUDP(host string, port int, request string, params *UDPPokeParams) UDPPo
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return ret
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}
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// continuousEcho() uses the same connection for multiple requests, made to run as a goroutine so that
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// manipulations can be made to the service and backend pods while a connection is ongoing
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// it starts by sending a series of packets to establish conntrack entries and waits for a signal to keep
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// sending packts. It returns an error if the number of failed attempts is >= 5
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func continuousEcho(host string, port int, timeout time.Duration, maxAttempts int, signal chan struct{}, errorChannel chan error) {
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defer ginkgo.GinkgoRecover()
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const threshold = 10
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// Sanity check inputs, because it has happened. These are the only things
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// that should hard fail the test - they are basically ASSERT()s.
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if host == "" {
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errorChannel <- fmt.Errorf("Got empty host for continuous echo (%s)", host)
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return
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}
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if port == 0 {
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errorChannel <- fmt.Errorf("Got port ==0 for continuous echo (%d)", port)
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return
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}
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hostPort := net.JoinHostPort(host, strconv.Itoa(port))
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url := fmt.Sprintf("udp://%s", hostPort)
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ret := UDPPokeResult{}
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con, err := net.Dial("udp", hostPort)
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if err != nil {
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ret.Status = UDPError
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ret.Error = err
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errorChannel <- fmt.Errorf("Connection to %q failed: %v", url, err)
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return
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}
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numErrors := 0
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bufsize := len(strconv.Itoa(maxAttempts)) + 1
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var buf = make([]byte, bufsize)
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for i := 0; i < maxAttempts; i++ {
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if i == threshold {
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framework.Logf("Continuous echo waiting for signal to continue")
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<-signal
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if numErrors == threshold {
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errorChannel <- fmt.Errorf("continuous echo was not able to communicate with initial server pod")
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return
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}
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}
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time.Sleep(1 * time.Second)
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err = con.SetDeadline(time.Now().Add(timeout))
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if err != nil {
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ret.Status = UDPError
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ret.Error = err
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framework.Logf("Continuous echo (%q): %v", url, err)
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numErrors++
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continue
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}
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myRequest := fmt.Sprintf("echo %d", i)
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_, err = con.Write([]byte(fmt.Sprintf("%s\n", myRequest)))
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if err != nil {
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ret.Error = err
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neterr, ok := err.(net.Error)
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if ok && neterr.Timeout() {
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ret.Status = UDPTimeout
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} else if strings.Contains(err.Error(), "connection refused") {
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ret.Status = UDPRefused
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} else {
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ret.Status = UDPError
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}
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numErrors++
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framework.Logf("Continuous echo (%q): %v - %d errors seen so far", url, err, numErrors)
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continue
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}
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err = con.SetDeadline(time.Now().Add(timeout))
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if err != nil {
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ret.Status = UDPError
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ret.Error = err
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numErrors++
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framework.Logf("Continuous echo (%q): %v - %d errors seen so far", url, err, numErrors)
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continue
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}
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n, err := con.Read(buf)
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if err != nil {
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ret.Error = err
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neterr, ok := err.(net.Error)
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if ok && neterr.Timeout() {
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ret.Status = UDPTimeout
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} else if strings.Contains(err.Error(), "connection refused") {
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ret.Status = UDPRefused
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} else {
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ret.Status = UDPError
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}
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numErrors++
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framework.Logf("Continuous echo (%q): %v - %d errors seen so far", url, err, numErrors)
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continue
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}
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ret.Response = buf[0:n]
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if string(ret.Response) != fmt.Sprintf("%d", i) {
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ret.Status = UDPBadResponse
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ret.Error = fmt.Errorf("response does not match expected string: %q", string(ret.Response))
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framework.Logf("Continuous echo (%q): %v", url, ret.Error)
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numErrors++
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continue
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}
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ret.Status = UDPSuccess
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framework.Logf("Continuous echo(%q): success", url)
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}
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err = nil
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if numErrors >= threshold {
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err = fmt.Errorf("Too many Errors in continuous echo")
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}
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errorChannel <- err
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}
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// testReachableUDP tests that the given host serves UDP on the given port.
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func testReachableUDP(host string, port int, timeout time.Duration) {
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pollfn := func() (bool, error) {
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@ -1240,69 +1123,6 @@ var _ = SIGDescribe("Services", func() {
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framework.ExpectNoError(verifyServeHostnameServiceUp(cs, ns, host, podNames2, svc2IP, servicePort))
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})
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ginkgo.It("should be able to preserve UDP traffic when server pod cycles for a NodePort service", func() {
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serviceName := "clusterip-test"
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serverPod1Name := "server-1"
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serverPod2Name := "server-2"
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ns := f.Namespace.Name
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nodeIP, err := e2enode.PickIP(cs) // for later
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framework.ExpectNoError(err)
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// Create a NodePort service
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udpJig := e2eservice.NewTestJig(cs, ns, serviceName)
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ginkgo.By("creating a UDP service " + serviceName + " with type=NodePort in " + ns)
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udpService, err := udpJig.CreateUDPService(func(svc *v1.Service) {
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svc.Spec.Type = v1.ServiceTypeNodePort
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svc.Spec.Ports = []v1.ServicePort{
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{Port: 80, Name: "http", Protocol: v1.ProtocolUDP, TargetPort: intstr.FromInt(80)},
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}
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})
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framework.ExpectNoError(err)
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// Add a backend pod to the service
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ginkgo.By("creating a backend pod for the service " + serviceName)
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serverPod1 := newAgnhostPod(serverPod1Name, "netexec", fmt.Sprintf("--udp-port=%d", 80))
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serverPod1.Labels = udpJig.Labels
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_, err = cs.CoreV1().Pods(ns).Create(context.TODO(), serverPod1, metav1.CreateOptions{})
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ginkgo.By(fmt.Sprintf("checking NodePort service %s on node with public IP %s", serviceName, nodeIP))
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framework.ExpectNoError(err)
|
||||
framework.ExpectNoError(e2epod.WaitTimeoutForPodReadyInNamespace(f.ClientSet, serverPod1.Name, f.Namespace.Name, framework.PodStartTimeout))
|
||||
|
||||
// Waiting for service to expose endpoint.
|
||||
err = validateEndpointsPorts(cs, ns, serviceName, portsByPodName{serverPod1Name: {80}})
|
||||
framework.ExpectNoError(err, "failed to validate endpoints for service %s in namespace: %s", serviceName, ns)
|
||||
|
||||
// Check that the pod reveives the traffic
|
||||
ginkgo.By("Sending UDP traffic to NodePort service " + serviceName + " on node with publicIP " + nodeIP)
|
||||
errorChannel := make(chan error)
|
||||
signal := make(chan struct{}, 1)
|
||||
go continuousEcho(nodeIP, int(udpService.Spec.Ports[0].NodePort), 3*time.Second, 20, signal, errorChannel)
|
||||
|
||||
// Create a second pod
|
||||
ginkgo.By("creating a second pod for the service " + serviceName)
|
||||
serverPod2 := newAgnhostPod(serverPod2Name, "netexec", fmt.Sprintf("--udp-port=%d", 80))
|
||||
serverPod2.Labels = udpJig.Labels
|
||||
_, err = cs.CoreV1().Pods(ns).Create(context.TODO(), serverPod2, metav1.CreateOptions{})
|
||||
framework.ExpectNoError(err)
|
||||
framework.ExpectNoError(e2epod.WaitTimeoutForPodReadyInNamespace(f.ClientSet, serverPod2.Name, f.Namespace.Name, framework.PodStartTimeout))
|
||||
|
||||
// and delete the first pod
|
||||
framework.Logf("Cleaning up %s pod", serverPod1Name)
|
||||
err = cs.CoreV1().Pods(ns).Delete(context.TODO(), serverPod1Name, metav1.DeleteOptions{})
|
||||
framework.ExpectNoError(err, "failed to delete pod: %s on node", serverPod1Name)
|
||||
|
||||
// Check that the second pod keeps receiving traffic
|
||||
ginkgo.By("Sending UDP traffic to NodePort service " + serviceName + " on node with publicIP " + nodeIP)
|
||||
signal <- struct{}{}
|
||||
|
||||
// Check that there are no errors
|
||||
err = <-errorChannel
|
||||
framework.ExpectNoError(err, "pod communication failed")
|
||||
|
||||
})
|
||||
|
||||
/*
|
||||
Release : v1.16
|
||||
Testname: Service, NodePort Service
|
||||
|
||||
Loading…
Reference in New Issue
Block a user