componentstatus: support client cert health check

etcd has support for client-cert-auth, which can be configured via the flag `--ca-file`,
when that is enabled, all the client requests must present with a client certificate,
however, the current component status check uses a single transport for all of the checks,
this is wrong, the checks should be different for each of different component, and make
each of them use different transport(tls configurations).

pkg/probe/http/http.go

@@ -32,7 +32,12 @@ import (
 
 func New() HTTPProber {
 	tlsConfig := &tls.Config{InsecureSkipVerify: true}
-	transport := utilnet.SetTransportDefaults(&http.Transport{TLSClientConfig: tlsConfig, DisableKeepAlives: true})
+	return NewWithTLSConfig(tlsConfig)
+}
+
+// NewWithTLSConfig takes tls config as parameter.
+func NewWithTLSConfig(config *tls.Config) HTTPProber {
+	transport := utilnet.SetTransportDefaults(&http.Transport{TLSClientConfig: config, DisableKeepAlives: true})
 	return httpProber{transport}
 }
 

pkg/registry/core/componentstatus/rest.go

@@ -27,19 +27,16 @@ import (
 	"k8s.io/apiserver/pkg/registry/rest"
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/probe"
-	httpprober "k8s.io/kubernetes/pkg/probe/http"
 )
 
 type REST struct {
-	GetServersToValidate func() map[string]Server
-	prober               httpprober.HTTPProber
+	GetServersToValidate func() map[string]*Server
 }
 
 // NewStorage returns a new REST.
-func NewStorage(serverRetriever func() map[string]Server) *REST {
+func NewStorage(serverRetriever func() map[string]*Server) *REST {
 	return &REST{
 		GetServersToValidate: serverRetriever,
-		prober:               httpprober.New(),
 	}
 }
 
@@ -60,7 +57,7 @@ func (rs *REST) List(ctx genericapirequest.Context, options *metainternalversion
 	wait.Add(len(servers))
 	statuses := make(chan api.ComponentStatus, len(servers))
 	for k, v := range servers {
-		go func(name string, server Server) {
+		go func(name string, server *Server) {
 			defer wait.Done()
 			status := rs.getComponentStatus(name, server)
 			statuses <- *status
@@ -97,8 +94,8 @@ func ToConditionStatus(s probe.Result) api.ConditionStatus {
 	}
 }
 
-func (rs *REST) getComponentStatus(name string, server Server) *api.ComponentStatus {
-	status, msg, err := server.DoServerCheck(rs.prober)
+func (rs *REST) getComponentStatus(name string, server *Server) *api.ComponentStatus {
+	status, msg, err := server.DoServerCheck()
 	errorMsg := ""
 	if err != nil {
 		errorMsg = err.Error()

pkg/registry/core/componentstatus/rest_test.go

@@ -50,17 +50,17 @@ type testResponse struct {
 }
 
 func NewTestREST(resp testResponse) *REST {
+	prober := &fakeHttpProber{
+		result: resp.result,
+		body:   resp.data,
+		err:    resp.err,
+	}
 	return &REST{
-		GetServersToValidate: func() map[string]Server {
-			return map[string]Server{
-				"test1": {Addr: "testserver1", Port: 8000, Path: "/healthz"},
+		GetServersToValidate: func() map[string]*Server {
+			return map[string]*Server{
+				"test1": {Addr: "testserver1", Port: 8000, Path: "/healthz", Prober: prober},
 			}
 		},
-		prober: &fakeHttpProber{
-			result: resp.result,
-			body:   resp.data,
-			err:    resp.err,
-		},
 	}
 }
 

pkg/registry/core/componentstatus/validator.go

@@ -17,8 +17,9 @@ limitations under the License.
 package componentstatus
 
 import (
+	"crypto/tls"
 	"net/http"
-
+	"sync"
 	"time"
 
 	utilnet "k8s.io/apimachinery/pkg/util/net"
@@ -42,7 +43,10 @@ type Server struct {
 	Port        int
 	Path        string
 	EnableHTTPS bool
+	TLSConfig   *tls.Config
 	Validate    ValidatorFn
+	Prober      httpprober.HTTPProber
+	Once        sync.Once
 }
 
 type ServerStatus struct {
@@ -58,14 +62,22 @@ type ServerStatus struct {
 	Err string `json:"err,omitempty"`
 }
 
-func (server *Server) DoServerCheck(prober httpprober.HTTPProber) (probe.Result, string, error) {
+func (server *Server) DoServerCheck() (probe.Result, string, error) {
+	// setup the prober
+	server.Once.Do(func() {
+		if server.Prober != nil {
+			return
+		}
+		server.Prober = httpprober.NewWithTLSConfig(server.TLSConfig)
+	})
+
 	scheme := "http"
 	if server.EnableHTTPS {
 		scheme = "https"
 	}
 	url := utilnet.FormatURL(scheme, server.Addr, server.Port, server.Path)
 
-	result, data, err := prober.Probe(url, nil, probeTimeOut)
+	result, data, err := server.Prober.Probe(url, nil, probeTimeOut)
 
 	if err != nil {
 		return probe.Unknown, "", err

pkg/registry/core/componentstatus/validator_test.go

@@ -59,7 +59,8 @@ func TestValidate(t *testing.T) {
 		}
 
 		s.Validate = test.validator
-		result, data, err := s.DoServerCheck(fakeProber)
+		s.Prober = fakeProber
+		result, data, err := s.DoServerCheck()
 		if test.expectErr && err == nil {
 			t.Error("unexpected non-error")
 		}

pkg/registry/core/rest/BUILD

@@ -15,6 +15,7 @@ go_test(
     tags = ["automanaged"],
     deps = [
         "//vendor/k8s.io/apimachinery/pkg/runtime/schema:go_default_library",
+        "//vendor/k8s.io/apiserver/pkg/server/storage:go_default_library",
         "//vendor/k8s.io/apiserver/pkg/storage/storagebackend:go_default_library",
     ],
 )

pkg/registry/core/rest/storage_core.go

@@ -242,14 +242,14 @@ type componentStatusStorage struct {
 	storageFactory serverstorage.StorageFactory
 }
 
-func (s componentStatusStorage) serversToValidate() map[string]componentstatus.Server {
-	serversToValidate := map[string]componentstatus.Server{
+func (s componentStatusStorage) serversToValidate() map[string]*componentstatus.Server {
+	serversToValidate := map[string]*componentstatus.Server{
 		"controller-manager": {Addr: "127.0.0.1", Port: ports.ControllerManagerPort, Path: "/healthz"},
 		"scheduler":          {Addr: "127.0.0.1", Port: ports.SchedulerPort, Path: "/healthz"},
 	}
 
 	for ix, machine := range s.storageFactory.Backends() {
-		etcdUrl, err := url.Parse(machine)
+		etcdUrl, err := url.Parse(machine.Server)
 		if err != nil {
 			glog.Errorf("Failed to parse etcd url for validation: %v", err)
 			continue
@@ -269,9 +269,10 @@ func (s componentStatusStorage) serversToValidate() map[string]componentstatus.S
 			port = 2379
 		}
 		// TODO: etcd health checking should be abstracted in the storage tier
-		serversToValidate[fmt.Sprintf("etcd-%d", ix)] = componentstatus.Server{
+		serversToValidate[fmt.Sprintf("etcd-%d", ix)] = &componentstatus.Server{
 			Addr:        addr,
 			EnableHTTPS: etcdUrl.Scheme == "https",
+			TLSConfig:   machine.TLSConfig,
 			Port:        port,
 			Path:        "/health",
 			Validate:    etcdutil.EtcdHealthCheck,

pkg/registry/core/rest/storage_core_test.go

@@ -20,6 +20,7 @@ import (
 	"testing"
 
 	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apiserver/pkg/server/storage"
 	"k8s.io/apiserver/pkg/storage/storagebackend"
 )
 
@@ -47,6 +48,6 @@ func (f fakeStorageFactory) ResourcePrefix(groupResource schema.GroupResource) s
 	return ""
 }
 
-func (f fakeStorageFactory) Backends() []string {
-	return []string{"etcd-0"}
+func (f fakeStorageFactory) Backends() []storage.Backend {
+	return []storage.Backend{{Server: "etcd-0"}}
 }

staging/src/k8s.io/apiserver/pkg/server/storage/storage_factory.go

@@ -17,6 +17,9 @@ limitations under the License.
 package storage
 
 import (
+	"crypto/tls"
+	"crypto/x509"
+	"io/ioutil"
 	"strings"
 
 	"github.com/golang/glog"
@@ -27,6 +30,15 @@ import (
 	"k8s.io/apiserver/pkg/storage/storagebackend"
 )
 
+// Backend describes the storage servers, the information here should be enough
+// for health validations.
+type Backend struct {
+	// the url of storage backend like: https://etcd.domain:2379
+	Server string
+	// the required tls config
+	TLSConfig *tls.Config
+}
+
 // StorageFactory is the interface to locate the storage for a given GroupResource
 type StorageFactory interface {
 	// New finds the storage destination for the given group and resource. It will
@@ -40,7 +52,7 @@ type StorageFactory interface {
 
 	// Backends gets all backends for all registered storage destinations.
 	// Used for getting all instances for health validations.
-	Backends() []string
+	Backends() []Backend
 }
 
 // DefaultStorageFactory takes a GroupResource and returns back its storage interface.  This result includes:
@@ -252,15 +264,45 @@ func (s *DefaultStorageFactory) NewConfig(groupResource schema.GroupResource) (*
 	return &storageConfig, nil
 }
 
-// Get all backends for all registered storage destinations.
+// Backends returns all backends for all registered storage destinations.
 // Used for getting all instances for health validations.
-func (s *DefaultStorageFactory) Backends() []string {
-	backends := sets.NewString(s.StorageConfig.ServerList...)
+func (s *DefaultStorageFactory) Backends() []Backend {
+	servers := sets.NewString(s.StorageConfig.ServerList...)
 
 	for _, overrides := range s.Overrides {
-		backends.Insert(overrides.etcdLocation...)
+		servers.Insert(overrides.etcdLocation...)
 	}
-	return backends.List()
+
+	tlsConfig := &tls.Config{
+		InsecureSkipVerify: true,
+	}
+	if len(s.StorageConfig.CertFile) > 0 && len(s.StorageConfig.KeyFile) > 0 {
+		cert, err := tls.LoadX509KeyPair(s.StorageConfig.CertFile, s.StorageConfig.KeyFile)
+		if err != nil {
+			glog.Errorf("failed to load key pair while getting backends: %s", err)
+		} else {
+			tlsConfig.Certificates = []tls.Certificate{cert}
+		}
+	}
+	if len(s.StorageConfig.CAFile) > 0 {
+		if caCert, err := ioutil.ReadFile(s.StorageConfig.CAFile); err != nil {
+			glog.Errorf("failed to read ca file while getting backends: %s", err)
+		} else {
+			caPool := x509.NewCertPool()
+			caPool.AppendCertsFromPEM(caCert)
+			tlsConfig.RootCAs = caPool
+			tlsConfig.InsecureSkipVerify = false
+		}
+	}
+
+	backends := []Backend{}
+	for server := range servers {
+		backends = append(backends, Backend{
+			Server:    server,
+			TLSConfig: tlsConfig,
+		})
+	}
+	return backends
 }
 
 func (s *DefaultStorageFactory) ResourcePrefix(groupResource schema.GroupResource) string {