✨ Add TLS serving option for metrics

pkg/manager/manager.go

@@ -164,6 +164,12 @@ type Options struct {
 	// It can be set to "0" to disable the metrics serving.
 	MetricsBindAddress string
 
+	// MetricsCertDir is the directory that contains the secure metrics server key and certificate.
+	// When is set, server would be served over TLS and look up the server key and certificate in
+	// {MetricsCertDir}/tls.key and {MetricsCertDir}/tls.crt. The server key and certificate
+	// must be named tls.key and tls.crt, respectively.
+	MetricsCertDir string
+
 	// HealthProbeBindAddress is the TCP address that the controller should bind to
 	// for serving health probes
 	HealthProbeBindAddress string
@@ -206,9 +212,11 @@ type Options struct {
 	EventBroadcaster record.EventBroadcaster
 
 	// Dependency injection for testing
-	newRecorderProvider    func(config *rest.Config, scheme *runtime.Scheme, logger logr.Logger, broadcaster record.EventBroadcaster) (recorder.Provider, error)
-	newResourceLock        func(config *rest.Config, recorderProvider recorder.Provider, options leaderelection.Options) (resourcelock.Interface, error)
-	newMetricsListener     func(addr string) (net.Listener, error)
+	newRecorderProvider      func(config *rest.Config, scheme *runtime.Scheme, logger logr.Logger, broadcaster record.EventBroadcaster) (recorder.Provider, error)
+	newResourceLock          func(config *rest.Config, recorderProvider recorder.Provider, options leaderelection.Options) (resourcelock.Interface, error)
+	newMetricsListener       func(addr string) (net.Listener, error)
+	newSecureMetricsListener func(addr, certDir string) (net.Listener, error)
+
 	newHealthProbeListener func(addr string) (net.Listener, error)
 }
 
@@ -299,9 +307,17 @@ func New(config *rest.Config, options Options) (Manager, error) {
 
 	// Create the metrics listener. This will throw an error if the metrics bind
 	// address is invalid or already in use.
-	metricsListener, err := options.newMetricsListener(options.MetricsBindAddress)
-	if err != nil {
-		return nil, err
+	var metricsListener net.Listener
+	if options.MetricsCertDir == "" {
+		metricsListener, err = options.newMetricsListener(options.MetricsBindAddress)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		metricsListener, err = options.newSecureMetricsListener(options.MetricsBindAddress, options.MetricsCertDir)
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	// By default we have no extra endpoints to expose on metrics http server.
@@ -410,6 +426,11 @@ func setOptionsDefaults(options Options) Options {
 	if options.newMetricsListener == nil {
 		options.newMetricsListener = metrics.NewListener
 	}
+
+	if options.newSecureMetricsListener == nil {
+		options.newSecureMetricsListener = metrics.NewSecureListener
+	}
+
 	leaseDuration, renewDeadline, retryPeriod := defaultLeaseDuration, defaultRenewDeadline, defaultRetryPeriod
 	if options.LeaseDuration == nil {
 		options.LeaseDuration = &leaseDuration

pkg/manager/manager_test.go

@@ -17,10 +17,12 @@ limitations under the License.
 package manager
 
 import (
+	"crypto/tls"
 	"fmt"
 	"io/ioutil"
 	"net"
 	"net/http"
+	"path/filepath"
 	rt "runtime"
 
 	"github.com/go-logr/logr"
@@ -233,6 +235,24 @@ var _ = Describe("manger.Manager", func() {
 			Expect(listener.Close()).ToNot(HaveOccurred())
 		})
 
+		It("should create a TLS listener for the metrics if certificates are provided and the address is correct", func() {
+			var listener net.Listener
+			certDir := filepath.Join(".", "testdata", "certs")
+			m, err := New(cfg, Options{
+				MetricsBindAddress: ":0",
+				MetricsCertDir:     certDir,
+				newSecureMetricsListener: func(addr, certDir string) (net.Listener, error) {
+					var err error
+					listener, err = metrics.NewSecureListener(addr, certDir)
+					return listener, err
+				},
+			})
+			Expect(m).ToNot(BeNil())
+			Expect(err).ToNot(HaveOccurred())
+			Expect(listener).ToNot(BeNil())
+			Expect(listener.Close()).ToNot(HaveOccurred())
+		})
+
 		It("should return an error if the metrics bind address is already in use", func() {
 			ln, err := metrics.NewListener(":0")
 			Expect(err).ShouldNot(HaveOccurred())
@@ -559,6 +579,76 @@ var _ = Describe("manger.Manager", func() {
 		})
 	})
 
+	Context("should start serving metrics over TLS", func() {
+		var listener net.Listener
+		var opts Options
+
+		BeforeEach(func() {
+			listener = nil
+			opts = Options{
+				MetricsCertDir: filepath.Join(".", "testdata", "certs"),
+				newSecureMetricsListener: func(addr, certDir string) (net.Listener, error) {
+					var err error
+					listener, err = metrics.NewSecureListener(addr, certDir)
+					return listener, err
+				},
+			}
+		})
+
+		AfterEach(func() {
+			if listener != nil {
+				listener.Close()
+			}
+		})
+
+		It("should serve secure metrics endpoint", func(done Done) {
+			opts.MetricsBindAddress = ":0"
+			m, err := New(cfg, opts)
+			Expect(err).NotTo(HaveOccurred())
+
+			s := make(chan struct{})
+			defer close(s)
+			go func() {
+				defer GinkgoRecover()
+				Expect(m.Start(s)).NotTo(HaveOccurred())
+				close(done)
+			}()
+
+			metricsEndpoint := fmt.Sprintf("https://%s/metrics", listener.Addr().String())
+			tr := &http.Transport{
+				TLSClientConfig: &tls.Config{
+					InsecureSkipVerify: true,
+				},
+			}
+			client := &http.Client{Transport: tr}
+			resp, err := client.Get(metricsEndpoint)
+			Expect(err).NotTo(HaveOccurred())
+			Expect(resp.StatusCode).To(Equal(200))
+		})
+
+		It("should not serve both endpoints", func(done Done) {
+			var insecureListener net.Listener
+			opts.MetricsBindAddress = ":0"
+			opts.newMetricsListener = func(addr string) (net.Listener, error) {
+				var err error
+				insecureListener, err = metrics.NewListener(addr)
+				return listener, err
+			}
+
+			m, err := New(cfg, opts)
+			Expect(err).NotTo(HaveOccurred())
+
+			s := make(chan struct{})
+			defer close(s)
+			go func() {
+				defer GinkgoRecover()
+				Expect(m.Start(s)).NotTo(HaveOccurred())
+				close(done)
+			}()
+			Expect(insecureListener).To(BeNil())
+		})
+	})
+
 	Context("should start serving health probes", func() {
 		var listener net.Listener
 		var opts Options

pkg/manager/testdata/certs/tls.crt

@@ -0,0 +1,18 @@
+-----BEGIN CERTIFICATE-----
+MIIC8zCCAdugAwIBAgIJAOBRXEjnBd8DMA0GCSqGSIb3DQEBBQUAMCQxIjAgBgNV
+BAMTGWh0dHBzbG9jYWxob3N0NDQ0M21ldHJpY3MwHhcNMjAwNjExMTEzMDI3WhcN
+MzAwNjA5MTEzMDI3WjAkMSIwIAYDVQQDExlodHRwc2xvY2FsaG9zdDQ0NDNtZXRy
+aWNzMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAxY6bVSLkfdHlI9kl
+4nAYTXCEdqEjVyrBQpwNeOkQ+E2hX2T28CBUPgWcHfD2wD85rVRh26Cs1ACifpIS
+SJI5nSswBqkA+whzV1uIofcjbxGFlVBfeOEQnbuXpHb60ZzgCVH5/9XIlw5NiR7V
+wfDzm9ZlNZzhCI8dGYFObop3fUfunmublUUyrmkxxdyFAC09w2NYijha+kz0FkGF
+Ao/4Ppqa4lFBYTR41wh5XM3cZFPUTrAw4W3gc64KQIuwXNeUxYYgBA/Xpoz5EQey
+jH/OVKFNKM6IKZNxyx5f9LQ9Lgzl0Vt7jjvjaGsQQ+4c9Ea6eBA9NlaKyzxyILlV
+vAnw1QIDAQABoygwJjAkBgNVHREEHTAbghlodHRwc2xvY2FsaG9zdDQ0NDNtZXRy
+aWNzMA0GCSqGSIb3DQEBBQUAA4IBAQBJBGV7xTrxFGyPNWautrTGo65/fCv7ddra
++1Kkh0Hlf/m9ZXRBkDW7SVlNYV+Uag/jVyT/OfYTe6TO1rxI/0L8gQhXPZ9n59cH
+O8mfT+/bk1CzaUV0pKpf4fO87twLXgp0VSRPkCE3PG3xzhGrbaB36dS8Ploz9nWE
+mG3NAsVc4jXYoVKZBmFCwew5h9IobqXACdWX9ik2eMS5oAOp+U7L1RZQjlXFWxEO
+46TgvNxQP6IPQZlR4ed4j7viY/KSm2FXKKNVjtXLBlGKfdPuKEtCL1axrFWumFi2
+CcOjeGbwwUn602Pd3lNj/GwaKdzC40n9/r7JalgVs3Jc+oiGfZJ9
+-----END CERTIFICATE-----

pkg/manager/testdata/certs/tls.key

@@ -0,0 +1,27 @@
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----

pkg/metrics/listener.go

@@ -17,9 +17,13 @@ limitations under the License.
 package metrics
 
 import (
+	"context"
+	"crypto/tls"
 	"fmt"
 	"net"
+	"path/filepath"
 
+	"sigs.k8s.io/controller-runtime/pkg/internal/certwatcher"
 	logf "sigs.k8s.io/controller-runtime/pkg/internal/log"
 )
 
@@ -29,6 +33,12 @@ var log = logf.RuntimeLog.WithName("metrics")
 // The metrics is on by default.
 var DefaultBindAddress = ":8080"
 
+// DefaultKeyPath is prefix path for TLS key
+var DefaultKeyPath = "tls.key"
+
+// DefualtCertPath is prefix path for TLS certificate
+var DefualtCertPath = "tls.crt"
+
 // NewListener creates a new TCP listener bound to the given address.
 func NewListener(addr string) (net.Listener, error) {
 	if addr == "" {
@@ -44,9 +54,39 @@ func NewListener(addr string) (net.Listener, error) {
 	log.Info("metrics server is starting to listen", "addr", addr)
 	ln, err := net.Listen("tcp", addr)
 	if err != nil {
-		er := fmt.Errorf("error listening on %s: %w", addr, err)
-		log.Error(er, "metrics server failed to listen. You may want to disable the metrics server or use another port if it is due to conflicts")
-		return nil, er
+		err = fmt.Errorf("error listening on %s: %w", addr, err)
+		log.Error(err, "metrics server failed to listen. You may want to disable the metrics server or use another port if it is due to conflicts")
+		return nil, err
 	}
+
 	return ln, nil
 }
+
+// NewSecureListener creates a new TCP listener over TLS bound to the given address.
+func NewSecureListener(addr, certDir string) (net.Listener, error) {
+	ln, err := NewListener(addr)
+	if err != nil {
+		return nil, err
+	}
+
+	certPath := filepath.Join(certDir, DefualtCertPath)
+	certKey := filepath.Join(certDir, DefaultKeyPath)
+	certWatcher, err := certwatcher.New(certPath, certKey)
+	if err != nil {
+		return nil, err
+	}
+
+	go func() {
+		if err := certWatcher.Start(context.Background().Done()); err != nil {
+			log.Error(err, "certificate watcher error")
+			return
+		}
+	}()
+
+	cfg := &tls.Config{
+		NextProtos:     []string{"h2"},
+		GetCertificate: certWatcher.GetCertificate,
+	}
+
+	return tls.NewListener(ln, cfg), nil
+}

pkg/webhook/server.go

@@ -31,8 +31,9 @@ import (
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
+
+	"sigs.k8s.io/controller-runtime/pkg/internal/certwatcher"
 	"sigs.k8s.io/controller-runtime/pkg/runtime/inject"
-	"sigs.k8s.io/controller-runtime/pkg/webhook/internal/certwatcher"
 	"sigs.k8s.io/controller-runtime/pkg/webhook/internal/metrics"
 )