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e2e network test for udp services with hostNetwork clients

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There are some implementations of service that use socket loadbalancing
instead of NAT. These implementations don't need to deal with the
conntrack cleanup, however, they need to cleanup the sockets that are
no longer needed, so the application does not get stuck forever.

This can  happen in both TCP or UDP, but since UDP is stateless, the
situation is much complicated because does not have mechanisms like TCP
to detect that socket is no longer needed.

Change-Id: Ic2cfbdf6c8b1f1335e8b5964825dd1fa716fef53
This commit is contained in:
Antonio Ojea 2023-08-21 13:39:39 +00:00
parent bcbceea117
commit 039859b9b7
1 changed files with 77 additions and 0 deletions
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77
test/e2e/network/conntrack.go
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@ -281,6 +281,83 @@ var _ = common.SIGDescribe("Conntrack", func() {
}
})
ginkgo.It("should be able to preserve UDP traffic when server pod cycles for a ClusterIP service and client is hostNetwork", func(ctx context.Context) {
// Create a ClusterIP service
udpJig := e2eservice.NewTestJig(cs, ns, serviceName)
ginkgo.By("creating a UDP service " + serviceName + " with type=ClusterIP in " + ns)
udpService, err := udpJig.CreateUDPService(ctx, func(svc *v1.Service) {
svc.Spec.Type = v1.ServiceTypeClusterIP
svc.Spec.Ports = []v1.ServicePort{
{Port: 80, Name: "udp", Protocol: v1.ProtocolUDP, TargetPort: intstr.FromInt32(80)},
}
})
framework.ExpectNoError(err)
// Create a pod in one node to create the UDP traffic against the ClusterIP service every 5 seconds
ginkgo.By("creating a client pod for probing the service " + serviceName)
clientPod := e2epod.NewAgnhostPod(ns, podClient, nil, nil, nil)
nodeSelection := e2epod.NodeSelection{Name: clientNodeInfo.name}
e2epod.SetNodeSelection(&clientPod.Spec, nodeSelection)
cmd := fmt.Sprintf(`date; for i in $(seq 1 3000); do echo "$(date) Try: ${i}"; echo hostname | nc -u -w 5 -p %d %s %d; echo; done`, srcPort, udpService.Spec.ClusterIP, udpService.Spec.Ports[0].Port)
clientPod.Spec.Containers[0].Command = []string{"/bin/sh", "-c", cmd}
clientPod.Spec.Containers[0].Name = podClient
clientPod.Spec.HostNetwork = true
e2epod.NewPodClient(fr).CreateSync(ctx, clientPod)
// Read the client pod logs
logs, err := e2epod.GetPodLogs(ctx, cs, ns, podClient, podClient)
framework.ExpectNoError(err)
framework.Logf("Pod client logs: %s", logs)
// Add a backend pod to the service in the other node
ginkgo.By("creating a backend pod " + podBackend1 + " for the service " + serviceName)
serverPod1 := e2epod.NewAgnhostPod(ns, podBackend1, nil, nil, nil, "netexec", fmt.Sprintf("--udp-port=%d", 80))
serverPod1.Labels = udpJig.Labels
nodeSelection = e2epod.NodeSelection{Name: serverNodeInfo.name}
e2epod.SetNodeSelection(&serverPod1.Spec, nodeSelection)
e2epod.NewPodClient(fr).CreateSync(ctx, serverPod1)
validateEndpointsPortsOrFail(ctx, cs, ns, serviceName, portsByPodName{podBackend1: {80}})
// Note that the fact that Endpoints object already exists, does NOT mean
// that iptables (or whatever else is used) was already programmed.
// Additionally take into account that UDP conntract entries timeout is
// 30 seconds by default.
// Based on the above check if the pod receives the traffic.
ginkgo.By("checking client pod connected to the backend 1 on Node IP " + serverNodeInfo.nodeIP)
if err := wait.PollImmediateWithContext(ctx, 5*time.Second, time.Minute, logContainsFn(podBackend1, podClient)); err != nil {
logs, err = e2epod.GetPodLogs(ctx, cs, ns, podClient, podClient)
framework.ExpectNoError(err)
framework.Logf("Pod client logs: %s", logs)
framework.Failf("Failed to connect to backend 1")
}
// Create a second pod
ginkgo.By("creating a second backend pod " + podBackend2 + " for the service " + serviceName)
serverPod2 := e2epod.NewAgnhostPod(ns, podBackend2, nil, nil, nil, "netexec", fmt.Sprintf("--udp-port=%d", 80))
serverPod2.Labels = udpJig.Labels
nodeSelection = e2epod.NodeSelection{Name: serverNodeInfo.name}
e2epod.SetNodeSelection(&serverPod2.Spec, nodeSelection)
e2epod.NewPodClient(fr).CreateSync(ctx, serverPod2)
// and delete the first pod
framework.Logf("Cleaning up %s pod", podBackend1)
e2epod.NewPodClient(fr).DeleteSync(ctx, podBackend1, metav1.DeleteOptions{}, e2epod.DefaultPodDeletionTimeout)
validateEndpointsPortsOrFail(ctx, cs, ns, serviceName, portsByPodName{podBackend2: {80}})
// Check that the second pod keeps receiving traffic
// UDP conntrack entries timeout is 30 sec by default
ginkgo.By("checking client pod connected to the backend 2 on Node IP " + serverNodeInfo.nodeIP)
if err := wait.PollImmediateWithContext(ctx, 5*time.Second, time.Minute, logContainsFn(podBackend2, podClient)); err != nil {
logs, err = e2epod.GetPodLogs(ctx, cs, ns, podClient, podClient)
framework.ExpectNoError(err)
framework.Logf("Pod client logs: %s", logs)
framework.Failf("Failed to connect to backend 2")
}
})
// Regression test for #105657
// 1. Create an UDP Service
// 2. Client Pod sending traffic to the UDP service