swtich ifdown/ifup to use ip link down/up instead

test/e2e/reboot.go

@@ -106,7 +106,7 @@ var _ = framework.KubeDescribe("Reboot [Disruptive] [Feature:Reboot]", func() {
 	It("each node by switching off the network interface and ensure they function upon switch on", func() {
 		// switch the network interface off for a while to simulate a network outage
 		// We sleep 10 seconds to give some time for ssh command to cleanly finish before network is down.
-		testReboot(f.Client, "nohup sh -c 'sleep 10 && sudo ifdown eth0 && sleep 120 && sudo ifup eth0' >/dev/null 2>&1 &")
+		testReboot(f.Client, "nohup sh -c 'sleep 10 && sudo ip link set eth0 down && sleep 120 && sudo ip link set eth0 up' >/dev/null 2>&1 &")
 	})
 
 	It("each node by dropping all inbound packets for a while and ensure they function afterwards", func() {