Add test case for live migration behavior

Signed-off-by: Zhuchen Wang <zcwang@google.com>

tests/vmi_vsock_test.go

@@ -25,6 +25,7 @@ import (
 	expect "github.com/google/goexpect"
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
+	k8sv1 "k8s.io/api/core/v1"
 	"k8s.io/utils/pointer"
 
 	virtconfig "kubevirt.io/kubevirt/pkg/virt-config"
@@ -46,7 +47,7 @@ var _ = Describe("[Serial][sig-compute]Vsock", func() {
 		Expect(err).ToNot(HaveOccurred())
 	})
 
-	Context("", func() {
+	Context("VM creation", func() {
 		It("should expose a Vsock device", func() {
 			checks.SkipTestIfNoFeatureGate(virtconfig.VsockGate)
 			By("Creating a VMI with Vsock enabled")
@@ -76,21 +77,70 @@ var _ = Describe("[Serial][sig-compute]Vsock", func() {
 				&expect.BSnd{S: "ls /dev/vsock\n"},
 				&expect.BExp{R: "/dev/vsock"},
 			}, 300)).To(Succeed(), "Could not find a vsock device")
+		})
+	})
+
+	Context("Live migration", func() {
+		affinity := &k8sv1.Affinity{
+			NodeAffinity: &k8sv1.NodeAffinity{
+				PreferredDuringSchedulingIgnoredDuringExecution: []k8sv1.PreferredSchedulingTerm{
+					{
+						Preference: k8sv1.NodeSelectorTerm{
+							MatchExpressions: []k8sv1.NodeSelectorRequirement{
+								{
+									Key:      "kubernetes.io/hostname",
+									Operator: k8sv1.NodeSelectorOpIn,
+									Values:   []string{"node02"},
+								},
+							},
+						},
+						Weight: 1,
+					},
+				},
+			},
+		}
+
+		It("migrate the vmi with CID 4", func() {
+			checks.SkipTestIfNoFeatureGate(virtconfig.VsockGate)
+			By("Creating a VMI with Vsock enabled")
+			vmi := tests.NewRandomFedoraVMI()
+			vmi.Spec.Domain.Devices.AutoattachVsock = pointer.Bool(true)
+			vmi.Spec.Affinity = affinity
+			vmi = tests.RunVMIAndExpectLaunch(vmi, 60)
+
+			By("creating valid libvirt domain")
+			domain, err := tests.GetRunningVirtualMachineInstanceDomainXML(virtClient, vmi)
+			Expect(err).ToNot(HaveOccurred())
+			domSpec := &api.DomainSpec{}
+			Expect(xml.Unmarshal([]byte(domain), domSpec)).To(Succeed())
+			Expect(domSpec.Devices.Vsock.CID.Auto).To(Equal("no"))
+			Expect(domSpec.Devices.Vsock.CID.Address).To(Equal("3"))
+
+			By("Creating a new VMI with Vsock enabled on the same node")
+			vmi2 := tests.NewRandomFedoraVMI()
+			vmi2.Spec.Domain.Devices.AutoattachVsock = pointer.Bool(true)
+			vmi2.Spec.Affinity = affinity
+			vmi2 = tests.RunVMIAndExpectLaunch(vmi2, 60)
+
+			By("creating valid libvirt domain")
+			domain2, err := tests.GetRunningVirtualMachineInstanceDomainXML(virtClient, vmi2)
+			Expect(err).ToNot(HaveOccurred())
+			domSpec2 := &api.DomainSpec{}
+			Expect(xml.Unmarshal([]byte(domain2), domSpec2)).To(Succeed())
+			Expect(domSpec2.Devices.Vsock.CID.Auto).To(Equal("no"))
+			Expect(domSpec2.Devices.Vsock.CID.Address).To(Equal("4"))
 
-			By("Migrating the VMI")
+			By("Migrating the 2nd VMI")
 			checks.SkipIfMigrationIsNotPossible()
-			migration := tests.NewRandomMigration(vmi.Name, vmi.Namespace)
+			migration := tests.NewRandomMigration(vmi2.Name, vmi2.Namespace)
 			tests.RunMigrationAndExpectCompletion(virtClient, migration, tests.MigrationWaitTime)
 
-			By("Ensuring the Vsock is still present")
-			Expect(console.SafeExpectBatch(vmi, []expect.Batcher{
-				&expect.BSnd{S: "ls /dev/vsock-vhost\n"},
-				&expect.BExp{R: "/dev/vsock-vhost"},
-			}, 300)).To(Succeed(), "Could not find a vsock-vhost device")
-			Expect(console.SafeExpectBatch(vmi, []expect.Batcher{
-				&expect.BSnd{S: "ls /dev/vsock\n"},
-				&expect.BExp{R: "/dev/vsock"},
-			}, 300)).To(Succeed(), "Could not find a vsock device")
+			domain2, err = tests.GetRunningVirtualMachineInstanceDomainXML(virtClient, vmi2)
+			Expect(err).ToNot(HaveOccurred())
+			domSpec2 = &api.DomainSpec{}
+			Expect(xml.Unmarshal([]byte(domain2), domSpec2)).To(Succeed())
+			Expect(domSpec2.Devices.Vsock.CID.Auto).To(Equal("no"))
+			Expect(domSpec2.Devices.Vsock.CID.Address).To(Equal("4")) // Libevirt retain the CID. The virt-handler allocation doesn't work in live migration
 		})
 	})
 })