e2e tests: Enables should test kubelet managed /etc/hosts file for Windows

We previously skipped this test because Docker did not support mounting
individual files in Containers.

Since then, support for Docker has been removed, and containerd on Windows
supports this feature. We can run this test on Windows.

Author: claudiubelu

test/conformance/testdata/conformance.yaml

@@ -2221,15 +2221,14 @@
   file: test/e2e/common/node/kubelet.go
 - testname: Kubelet, managed etc hosts
   codename: '[sig-node] KubeletManagedEtcHosts should test kubelet managed /etc/hosts
-    file [LinuxOnly] [NodeConformance] [Conformance]'
+    file [NodeConformance] [Conformance]'
   description: Create a Pod with containers with hostNetwork set to false, one of
     the containers mounts the /etc/hosts file form the host. Create a second Pod with
     hostNetwork set to true. 1. The Pod with hostNetwork=false MUST have /etc/hosts
     of containers managed by the Kubelet. 2. The Pod with hostNetwork=false but the
     container mounts /etc/hosts file from the host. The /etc/hosts file MUST not be
     managed by the Kubelet. 3. The Pod with hostNetwork=true , /etc/hosts file MUST
-    not be managed by the Kubelet. This test is marked LinuxOnly since Windows cannot
-    mount individual files in Containers.
+    not be managed by the Kubelet.
   release: v1.9
   file: test/e2e/common/node/kubelet_etc_hosts.go
 - testname: lease API should be available

test/e2e/common/node/kubelet_etc_hosts.go

@@ -31,11 +31,13 @@ import (
 )
 
 const (
-	etcHostsPodName            = "test-pod"
-	etcHostsHostNetworkPodName = "test-host-network-pod"
-	etcHostsPartialContent     = "# Kubernetes-managed hosts file."
-	etcHostsPath               = "/etc/hosts"
-	etcHostsOriginalPath       = "/etc/hosts-original"
+	etcHostsPodName             = "test-pod"
+	etcHostsHostNetworkPodName  = "test-host-network-pod"
+	etcHostsPartialContent      = "# Kubernetes-managed hosts file."
+	etcHostsPathLinux           = "/etc/hosts"
+	etcHostsPathWindows         = `C:\Windows\System32\drivers\etc\hosts`
+	etcHostsOriginalPathLinux   = "/etc/hosts-original"
+	etcHostsOriginalPathWindows = `C:\Windows\System32\drivers\etc\hosts-original`
 )
 
 // KubeletManagedHostConfig defines the types for running managed etc hosts test cases
@@ -59,9 +61,8 @@ var _ = SIGDescribe("KubeletManagedEtcHosts", func() {
 			1. The Pod with hostNetwork=false MUST have /etc/hosts of containers managed by the Kubelet.
 			2. The Pod with hostNetwork=false but the container mounts /etc/hosts file from the host. The /etc/hosts file MUST not be managed by the Kubelet.
 			3. The Pod with hostNetwork=true , /etc/hosts file MUST not be managed by the Kubelet.
-		This test is marked LinuxOnly since Windows cannot mount individual files in Containers.
 	*/
-	framework.ConformanceIt("should test kubelet managed /etc/hosts file [LinuxOnly]", f.WithNodeConformance(), func(ctx context.Context) {
+	framework.ConformanceIt("should test kubelet managed /etc/hosts file", f.WithNodeConformance(), func(ctx context.Context) {
 		ginkgo.By("Setting up the test")
 		config.setup(ctx)
 
@@ -112,6 +113,7 @@ func assertManagedStatus(
 
 	retryCount := 0
 	etcHostsContent := ""
+	etcHostsPath, etcHostsOriginalPath := getEtcHostsPath()
 
 	for startTime := time.Now(); time.Since(startTime) < retryTimeout; {
 		etcHostsContent = config.getFileContents(podName, name, etcHostsPath)
@@ -155,6 +157,7 @@ func (config *KubeletManagedHostConfig) getFileContents(podName, containerName,
 func (config *KubeletManagedHostConfig) createPodSpec(podName string) *v1.Pod {
 	hostPathType := new(v1.HostPathType)
 	*hostPathType = v1.HostPathType(string(v1.HostPathFileOrCreate))
+	etcHostsPath, etcHostsOriginalPath := getEtcHostsPath()
 	mounts := []v1.VolumeMount{
 		{
 			Name:      "host-etc-hosts",
@@ -198,6 +201,7 @@ func (config *KubeletManagedHostConfig) createPodSpec(podName string) *v1.Pod {
 func (config *KubeletManagedHostConfig) createPodSpecWithHostNetwork(podName string) *v1.Pod {
 	hostPathType := new(v1.HostPathType)
 	*hostPathType = v1.HostPathType(string(v1.HostPathFileOrCreate))
+	etcHostsPath, etcHostsOriginalPath := getEtcHostsPath()
 	mounts := []v1.VolumeMount{
 		{
 			Name:      "host-etc-hosts",
@@ -230,3 +234,10 @@ func (config *KubeletManagedHostConfig) createPodSpecWithHostNetwork(podName str
 	}
 	return pod
 }
+
+func getEtcHostsPath() (string, string) {
+	if framework.NodeOSDistroIs("windows") {
+		return etcHostsPathWindows, etcHostsOriginalPathWindows
+	}
+	return etcHostsPathLinux, etcHostsOriginalPathLinux
+}