feat: thanos querier to thanos sidecar mTLS

Author: vyzigold

go.mod

@@ -6,6 +6,7 @@ require (
 	github.com/go-logr/logr v1.4.2
 	github.com/google/go-cmp v0.6.0
 	github.com/openshift/api v0.0.0-20240301093301-ce10821dc999
+	github.com/openshift/library-go v0.0.0-20240216151214-738f3fa4ccf8
 	github.com/pkg/errors v0.9.1
 	github.com/prometheus/common v0.59.1
 	github.com/rhobs/obo-prometheus-operator v0.77.1-rhobs1
@@ -106,6 +107,7 @@ require (
 	google.golang.org/protobuf v1.34.2 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
+	k8s.io/apiserver v0.31.1 // indirect
 	k8s.io/klog/v2 v2.130.1 // indirect
 	k8s.io/kube-openapi v0.0.0-20240903163716-9e1beecbcb38 // indirect
 	sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd // indirect

go.sum

@@ -188,6 +188,8 @@ github.com/opencontainers/go-digest v1.0.0 h1:apOUWs51W5PlhuyGyz9FCeeBIOUDA/6nW8
 github.com/opencontainers/go-digest v1.0.0/go.mod h1:0JzlMkj0TRzQZfJkVvzbP0HBR3IKzErnv2BNG4W4MAM=
 github.com/openshift/api v0.0.0-20240301093301-ce10821dc999 h1:+S998xHiJApsJZjRAO8wyedU9GfqFd8mtwWly6LqHDo=
 github.com/openshift/api v0.0.0-20240301093301-ce10821dc999/go.mod h1:CxgbWAlvu2iQB0UmKTtRu1YfepRg1/vJ64n2DlIEVz4=
+github.com/openshift/library-go v0.0.0-20240216151214-738f3fa4ccf8 h1:dKtHGYiOwl0DKZEWBW4MFWFS6IYW02AVD1WSuUAVwEo=
+github.com/openshift/library-go v0.0.0-20240216151214-738f3fa4ccf8/go.mod h1:ePlaOqUiPplRc++6aYdMe+2FmXb2xTNS9Nz5laG2YmI=
 github.com/opentracing/opentracing-go v1.2.0 h1:uEJPy/1a5RIPAJ0Ov+OIO8OxWu77jEv+1B0VhjKrZUs=
 github.com/opentracing/opentracing-go v1.2.0/go.mod h1:GxEUsuufX4nBwe+T+Wl9TAgYrxe9dPLANfrWvHYVTgc=
 github.com/pkg/browser v0.0.0-20240102092130-5ac0b6a4141c h1:+mdjkGKdHQG3305AYmdv1U2eRNDiU2ErMBj1gwrq8eQ=
@@ -357,6 +359,8 @@ k8s.io/apiextensions-apiserver v0.31.1 h1:L+hwULvXx+nvTYX/MKM3kKMZyei+UiSXQWciX/
 k8s.io/apiextensions-apiserver v0.31.1/go.mod h1:tWMPR3sgW+jsl2xm9v7lAyRF1rYEK71i9G5dRtkknoQ=
 k8s.io/apimachinery v0.31.1 h1:mhcUBbj7KUjaVhyXILglcVjuS4nYXiwC+KKFBgIVy7U=
 k8s.io/apimachinery v0.31.1/go.mod h1:rsPdaZJfTfLsNJSQzNHQvYoTmxhoOEofxtOsF3rtsMo=
+k8s.io/apiserver v0.31.1 h1:Sars5ejQDCRBY5f7R3QFHdqN3s61nhkpaX8/k1iEw1c=
+k8s.io/apiserver v0.31.1/go.mod h1:lzDhpeToamVZJmmFlaLwdYZwd7zB+WYRYIboqA1kGxM=
 k8s.io/client-go v0.31.1 h1:f0ugtWSbWpxHR7sjVpQwuvw9a3ZKLXX0u0itkFXufb0=
 k8s.io/client-go v0.31.1/go.mod h1:sKI8871MJN2OyeqRlmA4W4KM9KBdBUpDLu/43eGemCg=
 k8s.io/component-base v0.31.1 h1:UpOepcrX3rQ3ab5NB6g5iP0tvsgJWzxTyAo20sgYSy8=

pkg/assets/certificate_generator.go

@@ -0,0 +1,147 @@
+package assets
+
+import (
+	"crypto/rand"
+	"crypto/x509"
+	"fmt"
+	"math/big"
+	"time"
+
+	"github.com/go-logr/logr"
+	"github.com/openshift/library-go/pkg/crypto"
+	v1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/util/sets"
+	"k8s.io/apiserver/pkg/authentication/user"
+)
+
+const certificateLifetime = time.Duration(crypto.DefaultCertificateLifetimeInDays) * 24 * time.Hour
+const GRPCSecretName = "thanos-grpc-secret"
+
+// Taken from
+// https://github.com/openshift/library-go/blob/08c2fd1b452520da35ad210930ea9d100545589a/pkg/operator/certrotation/signer.go#L68-L86
+// without refresh time handling. We just take care of rotation if we reach 1/5 of the validity timespan before expiration.
+func needsNewCert(notBefore, notAfter time.Time, now func() time.Time) bool {
+	maxWait := notAfter.Sub(notBefore) / 5
+	latestTime := notAfter.Add(-maxWait)
+	return now().After(latestTime)
+}
+
+// Taken from
+// https://github.com/openshift/cluster-monitoring-operator/blob/765d0b0369b176a5997d787b6710783437172879/pkg/manifests/tls.go#L113
+func RotateGRPCSecret(s *v1.Secret, logger logr.Logger) (bool, error) {
+	var (
+		curCA, newCA              *crypto.CA
+		curCABytes, crtPresent    = s.Data["ca.crt"]
+		curCAKeyBytes, keyPresent = s.Data["ca.key"]
+		rotate                    = !crtPresent || !keyPresent
+	)
+
+	if crtPresent && keyPresent {
+		var err error
+		curCA, err = crypto.GetCAFromBytes(curCABytes, curCAKeyBytes)
+		if err != nil {
+			logger.Info(fmt.Sprintf("generating a new CA due to error reading CA: %v", err))
+			rotate = true
+		} else if needsNewCert(curCA.Config.Certs[0].NotBefore, curCA.Config.Certs[0].NotAfter, time.Now) {
+			logger.Info("generating new CA, because the current one is older than 1/5 of it validity timestamp")
+			rotate = true
+		}
+	}
+
+	if !rotate {
+		return rotate, nil
+	}
+
+	if curCA == nil {
+		newCAConfig, err := crypto.MakeSelfSignedCAConfig(
+			fmt.Sprintf("%s@%d", "openshift-cluster-monitoring", time.Now().Unix()),
+			crypto.DefaultCertificateLifetimeInDays,
+		)
+		if err != nil {
+			return rotate, fmt.Errorf("error generating self signed CA: %w", err)
+		}
+
+		newCA = &crypto.CA{
+			SerialGenerator: &crypto.RandomSerialGenerator{},
+			Config:          newCAConfig,
+		}
+	} else {
+		template := curCA.Config.Certs[0]
+		now := time.Now()
+		template.NotBefore = now.Add(-1 * time.Second)
+		template.NotAfter = now.Add(certificateLifetime)
+		template.SerialNumber = template.SerialNumber.Add(template.SerialNumber, big.NewInt(1))
+
+		newCACert, err := createCertificate(template, template, template.PublicKey, curCA.Config.Key)
+		if err != nil {
+			return rotate, fmt.Errorf("error rotating CA: %w", err)
+		}
+
+		newCA = &crypto.CA{
+			SerialGenerator: &crypto.RandomSerialGenerator{},
+			Config: &crypto.TLSCertificateConfig{
+				Certs: []*x509.Certificate{newCACert},
+				Key:   curCA.Config.Key,
+			},
+		}
+	}
+
+	newCABytes, newCAKeyBytes, err := newCA.Config.GetPEMBytes()
+	if err != nil {
+		return rotate, fmt.Errorf("error getting PEM bytes from CA: %w", err)
+	}
+
+	s.Data["ca.crt"] = newCABytes
+	s.Data["ca.key"] = newCAKeyBytes
+
+	{
+		cfg, err := newCA.MakeClientCertificateForDuration(
+			&user.DefaultInfo{
+				Name: "thanos-querier",
+			},
+			time.Duration(crypto.DefaultCertificateLifetimeInDays)*24*time.Hour,
+		)
+		if err != nil {
+			return rotate, fmt.Errorf("error making client certificate: %w", err)
+		}
+
+		crt, key, err := cfg.GetPEMBytes()
+		if err != nil {
+			return rotate, fmt.Errorf("error getting PEM bytes for thanos querier client certificate: %w", err)
+		}
+		s.Data["thanos-querier-client.crt"] = crt
+		s.Data["thanos-querier-client.key"] = key
+	}
+
+	{
+		cfg, err := newCA.MakeServerCert(
+			sets.NewString("prometheus-grpc"),
+			crypto.DefaultCertificateLifetimeInDays,
+		)
+		if err != nil {
+			return rotate, fmt.Errorf("error making server certificate: %w", err)
+		}
+
+		crt, key, err := cfg.GetPEMBytes()
+		if err != nil {
+			return rotate, fmt.Errorf("error getting PEM bytes for prometheus-k8s server certificate: %w", err)
+		}
+		s.Data["prometheus-server.crt"] = crt
+		s.Data["prometheus-server.key"] = key
+	}
+
+	return rotate, nil
+}
+
+// createCertificate creates a new certificate and returns it in x509.Certificate form.
+func createCertificate(template, parent *x509.Certificate, pub, priv interface{}) (*x509.Certificate, error) {
+	rawCert, err := x509.CreateCertificate(rand.Reader, template, parent, pub, priv)
+	if err != nil {
+		return nil, fmt.Errorf("error creating certificate: %w", err)
+	}
+	parsedCerts, err := x509.ParseCertificates(rawCert)
+	if err != nil {
+		return nil, fmt.Errorf("error parsing certificate: %w", err)
+	}
+	return parsedCerts[0], nil
+}

pkg/controllers/monitoring/monitoring-stack/components.go

@@ -1,6 +1,7 @@
 package monitoringstack
 
 import (
+	"fmt"
 	"reflect"
 
 	monv1 "github.com/rhobs/obo-prometheus-operator/pkg/apis/monitoring/v1"
@@ -12,6 +13,7 @@ import (
 	"k8s.io/utils/ptr"
 
 	stack "github.com/rhobs/observability-operator/pkg/apis/monitoring/v1alpha1"
+	"github.com/rhobs/observability-operator/pkg/assets"
 	"github.com/rhobs/observability-operator/pkg/reconciler"
 )
 
@@ -28,6 +30,7 @@ func stackComponentReconcilers(
 	thanos ThanosConfiguration,
 	prometheus PrometheusConfiguration,
 	alertmanager AlertmanagerConfiguration,
+	tlsHashes map[string]string,
 ) []reconciler.Reconciler {
 	prometheusName := ms.Name + "-prometheus"
 	alertmanagerName := ms.Name + "-alertmanager"
@@ -44,7 +47,7 @@ func stackComponentReconcilers(
 		reconciler.NewUpdater(newPrometheus(ms, prometheusName,
 			additionalScrapeConfigsSecretName,
 			instanceSelectorKey, instanceSelectorValue,
-			thanos, prometheus), ms),
+			thanos, prometheus, tlsHashes), ms),
 		reconciler.NewUpdater(newPrometheusService(ms, instanceSelectorKey, instanceSelectorValue), ms),
 		reconciler.NewUpdater(newThanosSidecarService(ms, instanceSelectorKey, instanceSelectorValue), ms),
 		reconciler.NewOptionalUpdater(newPrometheusPDB(ms, instanceSelectorKey, instanceSelectorValue), ms,
@@ -115,6 +118,7 @@ func newPrometheus(
 	instanceSelectorValue string,
 	thanosCfg ThanosConfiguration,
 	prometheusCfg PrometheusConfiguration,
+	tlsHashes map[string]string,
 ) *monv1.Prometheus {
 	prometheusSelector := ms.Spec.ResourceSelector
 
@@ -193,12 +197,33 @@ func newPrometheus(
 					}
 					return []monv1.EnableFeature{}
 				}(),
+				Volumes: []corev1.Volume{
+					{
+						Name: "thanos-tls-assets",
+						VolumeSource: corev1.VolumeSource{
+							Secret: &corev1.SecretVolumeSource{
+								SecretName: assets.GRPCSecretName,
+							},
+						},
+					},
+				},
 			},
 			Retention:             ms.Spec.Retention,
 			RuleSelector:          prometheusSelector,
 			RuleNamespaceSelector: ms.Spec.NamespaceSelector,
 			Thanos: &monv1.ThanosSpec{
 				Image: ptr.To(thanosCfg.Image),
+				GRPCServerTLSConfig: &monv1.TLSConfig{
+					CAFile:   "/etc/thanos/tls-assets/ca.crt",
+					CertFile: "/etc/thanos/tls-assets/prometheus-server.crt",
+					KeyFile:  "/etc/thanos/tls-assets/prometheus-server.key",
+				},
+				VolumeMounts: []corev1.VolumeMount{
+					{
+						Name:      "thanos-tls-assets",
+						MountPath: "/etc/thanos/tls-assets",
+					},
+				},
 			},
 		},
 	}
@@ -230,6 +255,14 @@ func newPrometheus(
 		prometheus.Spec.Secrets = append(prometheus.Spec.Secrets, tlsConfig.CertificateAuthority.Name)
 	}
 
+	if len(tlsHashes) > 0 {
+		tlsAnnotations := map[string]string{}
+		for name, hash := range tlsHashes {
+			tlsAnnotations[fmt.Sprintf("monitoring.openshift.io/%s-hash", name)] = hash
+		}
+		prometheus.Spec.CommonPrometheusFields.PodMetadata.Annotations = tlsAnnotations
+	}
+
 	if prometheusCfg.Image != "" {
 		prometheus.Spec.CommonPrometheusFields.Image = ptr.To(prometheusCfg.Image)
 	}

pkg/controllers/monitoring/monitoring-stack/controller.go

@@ -28,14 +28,18 @@ import (
 	policyv1 "k8s.io/api/policy/v1"
 	rbacv1 "k8s.io/api/rbac/v1"
 	"k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/types"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/builder"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/controller"
 	"sigs.k8s.io/controller-runtime/pkg/predicate"
 
 	stack "github.com/rhobs/observability-operator/pkg/apis/monitoring/v1alpha1"
+	"github.com/rhobs/observability-operator/pkg/assets"
+	"github.com/rhobs/observability-operator/pkg/controllers/monitoring/utils"
 )
 
 type resourceManager struct {
@@ -133,6 +137,42 @@ func RegisterWithManager(mgr ctrl.Manager, opts Options) error {
 func (rm resourceManager) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
 	logger := rm.logger.WithValues("stack", req.NamespacedName)
 	logger.Info("Reconciling monitoring stack")
+
+	gRPCSecret := v1.Secret{
+		TypeMeta: metav1.TypeMeta{
+			APIVersion: v1.SchemeGroupVersion.String(),
+			Kind:       "Secret",
+		},
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      assets.GRPCSecretName,
+			Namespace: req.Namespace,
+		},
+		Data: map[string][]byte{},
+	}
+	err := rm.k8sClient.Get(ctx,
+                types.NamespacedName{
+                        Name: assets.GRPCSecretName,
+                        Namespace: req.Namespace,
+                },
+                &gRPCSecret)
+	if client.IgnoreNotFound(err) != nil {
+		return ctrl.Result{}, err
+	}
+
+	rotate, err := assets.RotateGRPCSecret(&gRPCSecret, logger)
+	if err != nil {
+		return ctrl.Result{}, err
+	}
+	if rotate {
+		err = rm.k8sClient.Update(ctx, &gRPCSecret)
+		if errors.IsNotFound(err) {
+			err = rm.k8sClient.Create(ctx, &gRPCSecret)
+		}
+		if err != nil {
+			return ctrl.Result{}, err
+		}
+	}
+
 	ms, err := rm.getStack(ctx, req)
 	if err != nil {
 		// retry since some error has occured
@@ -149,12 +189,24 @@ func (rm resourceManager) Reconcile(ctx context.Context, req ctrl.Request) (ctrl
 		return ctrl.Result{}, nil
 	}
 
+	// querier <---> sidecar mTLS hashes
+	mTLSSecretKeys := []string{"prometheus-server.key", "prometheus-server.crt", "ca.crt"}
+	tlsHashes := map[string]string{}
+	for _, key := range mTLSSecretKeys {
+		hash, err := utils.HashOfTLSSecret(assets.GRPCSecretName, key, ms.Namespace, rm.k8sClient)
+		if err != nil {
+			return ctrl.Result{}, err
+		}
+		tlsHashes[fmt.Sprintf("%s-%s", assets.GRPCSecretName, key)] = hash
+	}
+
 	reconcilers := stackComponentReconcilers(ms,
 		rm.instanceSelectorKey,
 		rm.instanceSelectorValue,
 		rm.thanos,
 		rm.prometheus,
 		rm.alertmanager,
+		tlsHashes,
 	)
 	for _, reconciler := range reconcilers {
 		err := reconciler.Reconcile(ctx, rm.k8sClient, rm.scheme)