Remove no-longer-used TestUnderTemporaryNetworkFailure()

This was previously used by some autoscaling tests that have since
been removed. It is somewhat sketchy (and inherently [Disruptive]),
and depends on iptables (so would need to be updated to use nftables
at some point if we were keeping it). Given that it's now unused, just
remove it (as well as some helper functions that are no longer used by
anyone else as well).

Author: danwinship

test/e2e/framework/network/utils.go

@@ -45,7 +45,6 @@ import (
 	e2epod "k8s.io/kubernetes/test/e2e/framework/pod"
 	e2epodoutput "k8s.io/kubernetes/test/e2e/framework/pod/output"
 	e2eskipper "k8s.io/kubernetes/test/e2e/framework/skipper"
-	e2essh "k8s.io/kubernetes/test/e2e/framework/ssh"
 	imageutils "k8s.io/kubernetes/test/utils/image"
 	netutils "k8s.io/utils/net"
 )
@@ -1099,101 +1098,6 @@ func httpGetNoConnectionPoolTimeout(url string, timeout time.Duration) (*http.Re
 	return client.Get(url)
 }
 
-// TestUnderTemporaryNetworkFailure blocks outgoing network traffic on 'node'. Then runs testFunc and returns its status.
-// At the end (even in case of errors), the network traffic is brought back to normal.
-// This function executes commands on a node so it will work only for some
-// environments.
-func TestUnderTemporaryNetworkFailure(ctx context.Context, c clientset.Interface, ns string, node *v1.Node, testFunc func(ctx context.Context)) {
-	host, err := e2enode.GetSSHExternalIP(node)
-	if err != nil {
-		framework.Failf("Error getting node external ip : %v", err)
-	}
-	controlPlaneAddresses := framework.GetControlPlaneAddresses(ctx, c)
-	ginkgo.By(fmt.Sprintf("block network traffic from node %s to the control plane", node.Name))
-	defer func() {
-		// This code will execute even if setting the iptables rule failed.
-		// It is on purpose because we may have an error even if the new rule
-		// had been inserted. (yes, we could look at the error code and ssh error
-		// separately, but I prefer to stay on the safe side).
-		ginkgo.By(fmt.Sprintf("Unblock network traffic from node %s to the control plane", node.Name))
-		for _, instanceAddress := range controlPlaneAddresses {
-			UnblockNetwork(ctx, host, instanceAddress)
-		}
-	}()
-
-	framework.Logf("Waiting %v to ensure node %s is ready before beginning test...", resizeNodeReadyTimeout, node.Name)
-	if !e2enode.WaitConditionToBe(ctx, c, node.Name, v1.NodeReady, true, resizeNodeReadyTimeout) {
-		framework.Failf("Node %s did not become ready within %v", node.Name, resizeNodeReadyTimeout)
-	}
-	for _, instanceAddress := range controlPlaneAddresses {
-		BlockNetwork(ctx, host, instanceAddress)
-	}
-
-	framework.Logf("Waiting %v for node %s to be not ready after simulated network failure", resizeNodeNotReadyTimeout, node.Name)
-	if !e2enode.WaitConditionToBe(ctx, c, node.Name, v1.NodeReady, false, resizeNodeNotReadyTimeout) {
-		framework.Failf("Node %s did not become not-ready within %v", node.Name, resizeNodeNotReadyTimeout)
-	}
-
-	testFunc(ctx)
-	// network traffic is unblocked in a deferred function
-}
-
-// BlockNetwork blocks network between the given from value and the given to value.
-// The following helper functions can block/unblock network from source
-// host to destination host by manipulating iptable rules.
-// This function assumes it can ssh to the source host.
-//
-// Caution:
-// Recommend to input IP instead of hostnames. Using hostnames will cause iptables to
-// do a DNS lookup to resolve the name to an IP address, which will
-// slow down the test and cause it to fail if DNS is absent or broken.
-//
-// Suggested usage pattern:
-//
-//	func foo() {
-//		...
-//		defer UnblockNetwork(from, to)
-//		BlockNetwork(from, to)
-//		...
-//	}
-func BlockNetwork(ctx context.Context, from string, to string) {
-	framework.Logf("block network traffic from %s to %s", from, to)
-	iptablesRule := fmt.Sprintf("OUTPUT --destination %s --jump REJECT", to)
-	dropCmd := fmt.Sprintf("sudo iptables --insert %s", iptablesRule)
-	if result, err := e2essh.SSH(ctx, dropCmd, from, framework.TestContext.Provider); result.Code != 0 || err != nil {
-		e2essh.LogResult(result)
-		framework.Failf("Unexpected error: %v", err)
-	}
-}
-
-// UnblockNetwork unblocks network between the given from value and the given to value.
-func UnblockNetwork(ctx context.Context, from string, to string) {
-	framework.Logf("Unblock network traffic from %s to %s", from, to)
-	iptablesRule := fmt.Sprintf("OUTPUT --destination %s --jump REJECT", to)
-	undropCmd := fmt.Sprintf("sudo iptables --delete %s", iptablesRule)
-	// Undrop command may fail if the rule has never been created.
-	// In such case we just lose 30 seconds, but the cluster is healthy.
-	// But if the rule had been created and removing it failed, the node is broken and
-	// not coming back. Subsequent tests will run or fewer nodes (some of the tests
-	// may fail). Manual intervention is required in such case (recreating the
-	// cluster solves the problem too).
-	err := wait.PollUntilContextTimeout(ctx, time.Millisecond*100, time.Second*30, false, func(ctx context.Context) (bool, error) {
-		result, err := e2essh.SSH(ctx, undropCmd, from, framework.TestContext.Provider)
-		if result.Code == 0 && err == nil {
-			return true, nil
-		}
-		e2essh.LogResult(result)
-		if err != nil {
-			framework.Logf("Unexpected error: %v", err)
-		}
-		return false, nil
-	})
-	if err != nil {
-		framework.Failf("Failed to remove the iptable REJECT rule. Manual intervention is "+
-			"required on host %s: remove rule %s, if exists", from, iptablesRule)
-	}
-}
-
 // WaitForService waits until the service appears (exist == true), or disappears (exist == false)
 func WaitForService(ctx context.Context, c clientset.Interface, namespace, name string, exist bool, interval, timeout time.Duration) error {
 	err := wait.PollUntilContextTimeout(ctx, interval, timeout, true, func(ctx context.Context) (bool, error) {

test/e2e/framework/util.go

@@ -56,11 +56,6 @@ import (
 	netutils "k8s.io/utils/net"
 )
 
-const (
-	// TODO(justinsb): Avoid hardcoding this.
-	awsMasterIP = "172.20.0.9"
-)
-
 // DEPRECATED constants. Use the timeouts in framework.Framework instead.
 const (
 	// PodListTimeout is how long to wait for the pod to be listable.
@@ -678,38 +673,6 @@ func GetNodeExternalIPs(node *v1.Node) (ips []string) {
 	return
 }
 
-// getControlPlaneAddresses returns the externalIP, internalIP and hostname fields of control plane nodes.
-// If any of these is unavailable, empty slices are returned.
-func getControlPlaneAddresses(ctx context.Context, c clientset.Interface) ([]string, []string, []string) {
-	var externalIPs, internalIPs, hostnames []string
-
-	// Populate the internal IPs.
-	eps, err := c.CoreV1().Endpoints(metav1.NamespaceDefault).Get(ctx, "kubernetes", metav1.GetOptions{})
-	if err != nil {
-		Failf("Failed to get kubernetes endpoints: %v", err)
-	}
-	for _, subset := range eps.Subsets {
-		for _, address := range subset.Addresses {
-			if address.IP != "" {
-				internalIPs = append(internalIPs, address.IP)
-			}
-		}
-	}
-
-	// Populate the external IP/hostname.
-	hostURL, err := url.Parse(TestContext.Host)
-	if err != nil {
-		Failf("Failed to parse hostname: %v", err)
-	}
-	if netutils.ParseIPSloppy(hostURL.Host) != nil {
-		externalIPs = append(externalIPs, hostURL.Host)
-	} else {
-		hostnames = append(hostnames, hostURL.Host)
-	}
-
-	return externalIPs, internalIPs, hostnames
-}
-
 // GetControlPlaneNodes returns a list of control plane nodes
 func GetControlPlaneNodes(ctx context.Context, c clientset.Interface) *v1.NodeList {
 	allNodes, err := c.CoreV1().Nodes().List(ctx, metav1.ListOptions{})
@@ -737,30 +700,6 @@ func GetControlPlaneNodes(ctx context.Context, c clientset.Interface) *v1.NodeLi
 	return &cpNodes
 }
 
-// GetControlPlaneAddresses returns all IP addresses on which the kubelet can reach the control plane.
-// It may return internal and external IPs, even if we expect for
-// e.g. internal IPs to be used (issue #56787), so that we can be
-// sure to block the control plane fully during tests.
-func GetControlPlaneAddresses(ctx context.Context, c clientset.Interface) []string {
-	externalIPs, internalIPs, _ := getControlPlaneAddresses(ctx, c)
-
-	ips := sets.NewString()
-	switch TestContext.Provider {
-	case "gce":
-		for _, ip := range externalIPs {
-			ips.Insert(ip)
-		}
-		for _, ip := range internalIPs {
-			ips.Insert(ip)
-		}
-	case "aws":
-		ips.Insert(awsMasterIP)
-	default:
-		Failf("This test is not supported for provider %s and should be disabled", TestContext.Provider)
-	}
-	return ips.List()
-}
-
 // PrettyPrintJSON converts metrics to JSON format.
 func PrettyPrintJSON(metrics interface{}) string {
 	output := &bytes.Buffer{}