Remove docker health handler from kubelet /healthz

Docker's health is checked separately from kubelet by the processing monitoring
tool (e.g., supervisord). kubelet should not be killed when docker is down.
This change removes the docker health handler from kubelet's /healthz handler.

pkg/kubelet/server.go

@@ -48,7 +48,6 @@ import (
 	"k8s.io/kubernetes/pkg/healthz"
 	"k8s.io/kubernetes/pkg/httplog"
 	kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
-	"k8s.io/kubernetes/pkg/kubelet/dockertools"
 	"k8s.io/kubernetes/pkg/kubelet/portforward"
 	"k8s.io/kubernetes/pkg/types"
 	"k8s.io/kubernetes/pkg/util"
@@ -141,7 +140,6 @@ type AuthInterface interface {
 // For testablitiy.
 type HostInterface interface {
 	GetContainerInfo(podFullName string, uid types.UID, containerName string, req *cadvisorapi.ContainerInfoRequest) (*cadvisorapi.ContainerInfo, error)
-	GetContainerRuntimeVersion() (kubecontainer.Version, error)
 	GetRawContainerInfo(containerName string, req *cadvisorapi.ContainerInfoRequest, subcontainers bool) (map[string]*cadvisorapi.ContainerInfo, error)
 	GetCachedMachineInfo() (*cadvisorapi.MachineInfo, error)
 	GetPods() []*api.Pod
@@ -212,7 +210,6 @@ func (s *Server) InstallAuthFilter() {
 func (s *Server) InstallDefaultHandlers() {
 	healthz.InstallHandler(s.restfulCont,
 		healthz.PingHealthz,
-		healthz.NamedCheck("docker", s.dockerHealthCheck),
 		healthz.NamedCheck("syncloop", s.syncLoopHealthCheck),
 	)
 	var ws *restful.WebService
@@ -367,22 +364,6 @@ func (s *Server) error(w http.ResponseWriter, err error) {
 	http.Error(w, msg, http.StatusInternalServerError)
 }
 
-func (s *Server) dockerHealthCheck(req *http.Request) error {
-	version, err := s.host.GetContainerRuntimeVersion()
-	if err != nil {
-		return errors.New("unknown Docker version")
-	}
-	// Verify the docker version.
-	result, err := version.Compare(dockertools.MinimumDockerAPIVersion)
-	if err != nil {
-		return err
-	}
-	if result < 0 {
-		return fmt.Errorf("Docker version is too old: %q", version.String())
-	}
-	return nil
-}
-
 // Checks if kubelet's sync loop  that updates containers is working.
 func (s *Server) syncLoopHealthCheck(req *http.Request) error {
 	duration := s.host.ResyncInterval() * 2

pkg/kubelet/server_test.go

@@ -38,8 +38,6 @@ import (
 	apierrs "k8s.io/kubernetes/pkg/api/errors"
 	"k8s.io/kubernetes/pkg/auth/authorizer"
 	"k8s.io/kubernetes/pkg/auth/user"
-	kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
-	"k8s.io/kubernetes/pkg/kubelet/dockertools"
 	kubetypes "k8s.io/kubernetes/pkg/kubelet/types"
 	"k8s.io/kubernetes/pkg/types"
 	"k8s.io/kubernetes/pkg/util/httpstream"
@@ -56,7 +54,6 @@ type fakeKubelet struct {
 	runningPodsFunc                    func() ([]*api.Pod, error)
 	logFunc                            func(w http.ResponseWriter, req *http.Request)
 	runFunc                            func(podFullName string, uid types.UID, containerName string, cmd []string) ([]byte, error)
-	containerVersionFunc               func() (kubecontainer.Version, error)
 	execFunc                           func(pod string, uid types.UID, container string, cmd []string, in io.Reader, out, err io.WriteCloser, tty bool) error
 	attachFunc                         func(pod string, uid types.UID, container string, in io.Reader, out, err io.WriteCloser, tty bool) error
 	portForwardFunc                    func(name string, uid types.UID, port uint16, stream io.ReadWriteCloser) error
@@ -87,10 +84,6 @@ func (fk *fakeKubelet) GetRawContainerInfo(containerName string, req *cadvisorap
 	return fk.rawInfoFunc(req)
 }
 
-func (fk *fakeKubelet) GetContainerRuntimeVersion() (kubecontainer.Version, error) {
-	return fk.containerVersionFunc()
-}
-
 func (fk *fakeKubelet) GetCachedMachineInfo() (*cadvisorapi.MachineInfo, error) {
 	return fk.machineInfoFunc()
 }
@@ -161,9 +154,6 @@ type serverTestFramework struct {
 func newServerTest() *serverTestFramework {
 	fw := &serverTestFramework{}
 	fw.fakeKubelet = &fakeKubelet{
-		containerVersionFunc: func() (kubecontainer.Version, error) {
-			return dockertools.NewVersion("1.18")
-		},
 		hostnameFunc: func() string {
 			return "127.0.0.1"
 		},
@@ -505,9 +495,6 @@ func TestServeRunInContainerWithUID(t *testing.T) {
 
 func TestHealthCheck(t *testing.T) {
 	fw := newServerTest()
-	fw.fakeKubelet.containerVersionFunc = func() (kubecontainer.Version, error) {
-		return dockertools.NewVersion("1.18")
-	}
 	fw.fakeKubelet.hostnameFunc = func() string {
 		return "127.0.0.1"
 	}
@@ -520,13 +507,6 @@ func TestHealthCheck(t *testing.T) {
 		return "fake"
 	}
 	assertHealthIsOk(t, fw.testHTTPServer.URL+"/healthz")
-
-	//Test with old container runtime version
-	fw.fakeKubelet.containerVersionFunc = func() (kubecontainer.Version, error) {
-		return dockertools.NewVersion("1.16")
-	}
-
-	assertHealthFails(t, fw.testHTTPServer.URL+"/healthz", http.StatusInternalServerError)
 }
 
 func assertHealthFails(t *testing.T, httpURL string, expectedErrorCode int) {
@@ -714,9 +694,6 @@ func TestAuthorizationSuccess(t *testing.T) {
 
 func TestSyncLoopCheck(t *testing.T) {
 	fw := newServerTest()
-	fw.fakeKubelet.containerVersionFunc = func() (kubecontainer.Version, error) {
-		return dockertools.NewVersion("1.18")
-	}
 	fw.fakeKubelet.hostnameFunc = func() string {
 		return "127.0.0.1"
 	}