Merge pull request #59832 from shyamjvs/fix-fake-docker-client-ip-collision

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Fake docker-client assigns random IPs to containers

Fixes https://github.com/kubernetes/kubernetes/issues/59823

/cc @wojtek-t @Random-Liu

pkg/kubelet/dockershim/docker_sandbox_test.go

@@ -19,6 +19,7 @@ package dockershim
 import (
 	"errors"
 	"fmt"
+	"math/rand"
 	"net"
 	"testing"
 	"time"
@@ -96,10 +97,8 @@ func TestSandboxStatus(t *testing.T) {
 	labels := map[string]string{"label": "foobar1"}
 	annotations := map[string]string{"annotation": "abc"}
 	config := makeSandboxConfigWithLabelsAndAnnotations("foo", "bar", "1", 0, labels, annotations)
-
+	r := rand.New(rand.NewSource(0)).Uint32()
-	// TODO: The following variables depend on the internal
+	podIP := fmt.Sprintf("10.%d.%d.%d", byte(r>>16), byte(r>>8), byte(r))
-	// implementation of FakeDockerClient, and should be fixed.
-	fakeIP := "2.3.4.5"
 
 	state := runtimeapi.PodSandboxState_SANDBOX_READY
 	ct := int64(0)
@@ -107,7 +106,7 @@ func TestSandboxStatus(t *testing.T) {
 		State:     state,
 		CreatedAt: ct,
 		Metadata:  config.Metadata,
-		Network:   &runtimeapi.PodSandboxNetworkStatus{Ip: fakeIP},
+		Network:   &runtimeapi.PodSandboxNetworkStatus{Ip: podIP},
 		Linux: &runtimeapi.LinuxPodSandboxStatus{
 			Namespaces: &runtimeapi.Namespace{
 				Options: &runtimeapi.NamespaceOption{
@@ -160,10 +159,8 @@ func TestSandboxStatus(t *testing.T) {
 func TestSandboxStatusAfterRestart(t *testing.T) {
 	ds, _, fClock := newTestDockerService()
 	config := makeSandboxConfig("foo", "bar", "1", 0)
-
+	r := rand.New(rand.NewSource(0)).Uint32()
-	// TODO: The following variables depend on the internal
+	podIP := fmt.Sprintf("10.%d.%d.%d", byte(r>>16), byte(r>>8), byte(r))
-	// implementation of FakeDockerClient, and should be fixed.
-	fakeIP := "2.3.4.5"
 
 	state := runtimeapi.PodSandboxState_SANDBOX_READY
 	ct := int64(0)
@@ -171,7 +168,7 @@ func TestSandboxStatusAfterRestart(t *testing.T) {
 		State:     state,
 		CreatedAt: ct,
 		Metadata:  config.Metadata,
-		Network:   &runtimeapi.PodSandboxNetworkStatus{Ip: fakeIP},
+		Network:   &runtimeapi.PodSandboxNetworkStatus{Ip: podIP},
 		Linux: &runtimeapi.LinuxPodSandboxStatus{
 			Namespaces: &runtimeapi.Namespace{
 				Options: &runtimeapi.NamespaceOption{

pkg/kubelet/dockershim/docker_service_test.go

@@ -18,6 +18,7 @@ package dockershim
 
 import (
 	"errors"
+	"math/rand"
 	"testing"
 	"time"
 
@@ -44,7 +45,7 @@ func newTestNetworkPlugin(t *testing.T) *nettest.MockNetworkPlugin {
 
 func newTestDockerService() (*dockerService, *libdocker.FakeDockerClient, *clock.FakeClock) {
 	fakeClock := clock.NewFakeClock(time.Time{})
-	c := libdocker.NewFakeDockerClient().WithClock(fakeClock).WithVersion("1.11.2", "1.23")
+	c := libdocker.NewFakeDockerClient().WithClock(fakeClock).WithVersion("1.11.2", "1.23").WithRandSource(rand.NewSource(0))
 	pm := network.NewPluginManager(&network.NoopNetworkPlugin{})
 	return &dockerService{
 		client:            c,

pkg/kubelet/dockershim/libdocker/fake_client.go

@@ -61,6 +61,7 @@ type FakeDockerClient struct {
 	called               []calledDetail
 	pulled               []string
 	EnableTrace          bool
+	RandGenerator        *rand.Rand
 
 	// Created, Started, Stopped and Removed all contain container docker ID
 	Created []string
@@ -99,6 +100,7 @@ func NewFakeDockerClient() *FakeDockerClient {
 		EnableTrace:         true,
 		ImageInspects:       make(map[string]*dockertypes.ImageInspect),
 		ImageIDsNeedingAuth: make(map[string]dockertypes.AuthConfig),
+		RandGenerator:       rand.New(rand.NewSource(time.Now().UnixNano())),
 	}
 }
 
@@ -123,6 +125,13 @@ func (f *FakeDockerClient) WithTraceDisabled() *FakeDockerClient {
 	return f
 }
 
+func (f *FakeDockerClient) WithRandSource(source rand.Source) *FakeDockerClient {
+	f.Lock()
+	defer f.Unlock()
+	f.RandGenerator = rand.New(source)
+	return f
+}
+
 func (f *FakeDockerClient) appendCalled(callDetail calledDetail) {
 	if f.EnableTrace {
 		f.called = append(f.called, callDetail)
@@ -597,7 +606,8 @@ func (f *FakeDockerClient) StartContainer(id string) error {
 	container.State.Running = true
 	container.State.Pid = os.Getpid()
 	container.State.StartedAt = dockerTimestampToString(timestamp)
-	container.NetworkSettings.IPAddress = "2.3.4.5"
+	r := f.RandGenerator.Uint32()
+	container.NetworkSettings.IPAddress = fmt.Sprintf("10.%d.%d.%d", byte(r>>16), byte(r>>8), byte(r))
 	f.ContainerMap[id] = container
 	f.updateContainerStatus(id, StatusRunningPrefix)
 	f.normalSleep(200, 50, 50)