diff --git a/metropolis/node/kubernetes/pki/BUILD.bazel b/metropolis/node/kubernetes/pki/BUILD.bazel
new file mode 100644
index 0000000..f82603d
--- /dev/null
+++ b/metropolis/node/kubernetes/pki/BUILD.bazel
@@ -0,0 +1,19 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "ca.go",
+        "certificate.go",
+        "kubernetes.go",
+    ],
+    importpath = "git.monogon.dev/source/nexantic.git/metropolis/node/kubernetes/pki",
+    visibility = ["//metropolis/node:__subpackages__"],
+    deps = [
+        "//metropolis/node:go_default_library",
+        "//metropolis/node/core/logtree:go_default_library",
+        "@io_etcd_go_etcd//clientv3:go_default_library",
+        "@io_k8s_client_go//tools/clientcmd:go_default_library",
+        "@io_k8s_client_go//tools/clientcmd/api:go_default_library",
+    ],
+)
diff --git a/metropolis/node/kubernetes/pki/ca.go b/metropolis/node/kubernetes/pki/ca.go
new file mode 100644
index 0000000..64453cd
--- /dev/null
+++ b/metropolis/node/kubernetes/pki/ca.go
@@ -0,0 +1,151 @@
+// Copyright 2020 The Monogon Project Authors.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package pki
+
+import (
+	"context"
+	"crypto"
+	"crypto/ed25519"
+	"crypto/rand"
+	"crypto/sha1"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/asn1"
+	"fmt"
+	"math/big"
+	"time"
+
+	"go.etcd.io/etcd/clientv3"
+)
+
+// Issuer is a CA that can issue certificates. Two issuers are currently implemented:
+//  - SelfSigned, which will generated a certificate signed by its corresponding private key.
+//  - Certificate, which will use another existing Certificate as a CA.
+type Issuer interface {
+	// CACertificate returns the DER-encoded x509 certificate of the CA that will sign certificates when Issue is
+	// called, or nil if this is self-signing issuer.
+	CACertificate(ctx context.Context, kv clientv3.KV) ([]byte, error)
+	// Issue will generate a key and certificate signed by the Issuer. The returned certificate is x509 DER-encoded,
+	// while the key is a bare ed25519 key.
+	Issue(ctx context.Context, template x509.Certificate, kv clientv3.KV) (cert, key []byte, err error)
+}
+
+var (
+	// From RFC 5280 Section 4.1.2.5
+	unknownNotAfter = time.Unix(253402300799, 0)
+)
+
+// Workaround for https://github.com/golang/go/issues/26676 in Go's crypto/x509. Specifically Go
+// violates Section 4.2.1.2 of RFC 5280 without this.
+// Fixed for 1.15 in https://go-review.googlesource.com/c/go/+/227098/.
+//
+// Taken from https://github.com/FiloSottile/mkcert/blob/master/cert.go#L295 written by one of Go's
+// crypto engineers
+func calculateSKID(pubKey crypto.PublicKey) ([]byte, error) {
+	spkiASN1, err := x509.MarshalPKIXPublicKey(pubKey)
+	if err != nil {
+		return nil, err
+	}
+
+	var spki struct {
+		Algorithm        pkix.AlgorithmIdentifier
+		SubjectPublicKey asn1.BitString
+	}
+	_, err = asn1.Unmarshal(spkiASN1, &spki)
+	if err != nil {
+		return nil, err
+	}
+	skid := sha1.Sum(spki.SubjectPublicKey.Bytes)
+	return skid[:], nil
+}
+
+// issueCertificate is a generic low level certificate-and-key issuance function. If ca or cakey is null, the
+// certificate will be self-signed. The returned certificate is DER-encoded, while the returned key is internal.
+func issueCertificate(template x509.Certificate, ca *x509.Certificate, caKey interface{}) (cert, key []byte, err error) {
+	pubKey, privKey, err := ed25519.GenerateKey(rand.Reader)
+	if err != nil {
+		panic(err)
+	}
+
+	serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 127)
+	serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
+	if err != nil {
+		err = fmt.Errorf("failed to generate serial number: %w", err)
+		return
+	}
+
+	skid, err := calculateSKID(pubKey)
+	if err != nil {
+		return []byte{}, privKey, err
+	}
+
+	template.SerialNumber = serialNumber
+	template.NotBefore = time.Now()
+	template.NotAfter = unknownNotAfter
+	template.BasicConstraintsValid = true
+	template.SubjectKeyId = skid
+
+	// Set the AuthorityKeyID to the SKID of the signing certificate (or self, if self-signing).
+	if ca != nil && caKey != nil {
+		template.AuthorityKeyId = ca.AuthorityKeyId
+	} else {
+		template.AuthorityKeyId = template.SubjectKeyId
+	}
+
+	if ca == nil || caKey == nil {
+		ca = &template
+		caKey = privKey
+	}
+
+	caCertRaw, err := x509.CreateCertificate(rand.Reader, &template, ca, pubKey, caKey)
+	return caCertRaw, privKey, err
+}
+
+type selfSigned struct{}
+
+func (s *selfSigned) Issue(ctx context.Context, template x509.Certificate, kv clientv3.KV) (cert, key []byte, err error) {
+	return issueCertificate(template, nil, nil)
+}
+
+func (s *selfSigned) CACertificate(ctx context.Context, kv clientv3.KV) ([]byte, error) {
+	return nil, nil
+}
+
+var (
+	// SelfSigned is an Issuer that generates self-signed certificates.
+	SelfSigned = &selfSigned{}
+)
+
+func (c *Certificate) Issue(ctx context.Context, template x509.Certificate, kv clientv3.KV) (cert, key []byte, err error) {
+	caCert, caKey, err := c.ensure(ctx, kv)
+	if err != nil {
+		return nil, nil, fmt.Errorf("could not ensure CA certificate %q exists: %w", c.name, err)
+	}
+
+	ca, err := x509.ParseCertificate(caCert)
+	if err != nil {
+		return nil, nil, fmt.Errorf("could not parse CA certificate: %w", err)
+	}
+	// Ensure only one level of CAs exist, and that they are created explicitly.
+	template.IsCA = false
+	return issueCertificate(template, ca, ed25519.PrivateKey(caKey))
+}
+
+func (c *Certificate) CACertificate(ctx context.Context, kv clientv3.KV) ([]byte, error) {
+	cert, _, err := c.ensure(ctx, kv)
+	return cert, err
+}
diff --git a/metropolis/node/kubernetes/pki/certificate.go b/metropolis/node/kubernetes/pki/certificate.go
new file mode 100644
index 0000000..6bd50f9
--- /dev/null
+++ b/metropolis/node/kubernetes/pki/certificate.go
@@ -0,0 +1,192 @@
+// Copyright 2020 The Monogon Project Authors.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package pki
+
+import (
+	"context"
+	"crypto/ed25519"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"fmt"
+	"net"
+
+	"go.etcd.io/etcd/clientv3"
+)
+
+// Certificate is the promise of a Certificate being available to the caller. In this case, Certificate refers to a
+// pair of x509 certificate and corresponding private key.
+// Certificates can be stored in etcd, and their issuers might also be store on etcd. As such, this type's methods
+// contain references to an etcd KV client.
+// This Certificate type is agnostic to usage, but mostly geared towards Kubernetes certificates.
+type Certificate struct {
+	// issuer is the Issuer that will generate this certificate if one doesn't yet exist or etcd, or the requested
+	// certificate is volatile (not to be stored on etcd).
+	issuer Issuer
+	// name is a unique key for storing the certificate in etcd. If empty, certificate is 'volatile', will not be stored
+	// on etcd, and every .Ensure() call will generate a new pair.
+	name string
+	// template is an x509 certificate definition that will be used to generate the certificate when issuing it.
+	template x509.Certificate
+}
+
+const (
+	// etcdPrefix is where all the PKI data is stored in etcd.
+	etcdPrefix = "/kube-pki/"
+)
+
+func etcdPath(f string, args ...interface{}) string {
+	return etcdPrefix + fmt.Sprintf(f, args...)
+}
+
+// New creates a new Certificate, or to be more precise, a promise that a certificate will exist once Ensure is called.
+// Issuer must be a valid certificate issuer (SelfSigned or another Certificate). Name must be unique among all
+// certificates, or empty (which will cause the certificate to be volatile, ie. not stored in etcd).
+func New(issuer Issuer, name string, template x509.Certificate) *Certificate {
+	return &Certificate{
+		issuer:   issuer,
+		name:     name,
+		template: template,
+	}
+}
+
+// Client makes a Kubernetes PKI-compatible client certificate template.
+// Directly derived from Kubernetes PKI requirements documented at
+// https://kubernetes.io/docs/setup/best-practices/certificates/#configure-certificates-manually
+func Client(identity string, groups []string) x509.Certificate {
+	return x509.Certificate{
+		Subject: pkix.Name{
+			CommonName:   identity,
+			Organization: groups,
+		},
+		KeyUsage:    x509.KeyUsageDigitalSignature | x509.KeyUsageKeyEncipherment,
+		ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
+	}
+}
+
+// Server makes a Kubernetes PKI-compatible server certificate template.
+func Server(dnsNames []string, ips []net.IP) x509.Certificate {
+	return x509.Certificate{
+		Subject:     pkix.Name{},
+		KeyUsage:    x509.KeyUsageDigitalSignature | x509.KeyUsageKeyEncipherment,
+		ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
+		DNSNames:    dnsNames,
+		IPAddresses: ips,
+	}
+}
+
+// CA makes a Certificate that can sign other certificates.
+func CA(cn string) x509.Certificate {
+	return x509.Certificate{
+		Subject: pkix.Name{
+			CommonName: cn,
+		},
+		IsCA:        true,
+		KeyUsage:    x509.KeyUsageCertSign | x509.KeyUsageCRLSign | x509.KeyUsageDigitalSignature,
+		ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth, x509.ExtKeyUsageServerAuth, x509.ExtKeyUsageOCSPSigning},
+	}
+}
+
+func (c *Certificate) etcdPaths() (cert, key string) {
+	return etcdPath("%s-cert.der", c.name), etcdPath("%s-key.der", c.name)
+}
+
+// ensure returns a DER-encoded x509 certificate and internally encoded bare ed25519 key for a given Certificate,
+// in memory (if volatile), loading it from etcd, or creating and saving it on etcd if needed.
+// This function is safe to call in parallel from multiple etcd clients (including across machines), but it will error
+// in case a concurrent certificate generation happens. These errors are, however, safe to retry - as long as all the
+// certificate creators (ie., Smalltown nodes) run the same version of this code.
+// TODO(q3k): in the future, this should be handled better - especially as we introduce new certificates, or worse,
+// change the issuance chain. As a stopgap measure, an explicit per-certificate or even global lock can be implemented.
+// And, even before that, we can handle concurrency errors in a smarter way.
+func (c *Certificate) ensure(ctx context.Context, kv clientv3.KV) (cert, key []byte, err error) {
+	if c.name == "" {
+		// Volatile certificate - generate.
+		// TODO(q3k): cache internally?
+		cert, key, err = c.issuer.Issue(ctx, c.template, kv)
+		if err != nil {
+			err = fmt.Errorf("failed to issue: %w", err)
+			return
+		}
+		return
+	}
+
+	certPath, keyPath := c.etcdPaths()
+
+	// Try loading certificate and key from etcd.
+	certRes, err := kv.Get(ctx, certPath)
+	if err != nil {
+		err = fmt.Errorf("failed to get certificate from etcd: %w", err)
+		return
+	}
+	keyRes, err := kv.Get(ctx, keyPath)
+	if err != nil {
+		err = fmt.Errorf("failed to get key from etcd: %w", err)
+		return
+	}
+
+	if len(certRes.Kvs) == 1 && len(keyRes.Kvs) == 1 {
+		// Certificate and key exists in etcd, return that.
+		cert = certRes.Kvs[0].Value
+		key = keyRes.Kvs[0].Value
+
+		err = nil
+		// TODO(q3k): check for expiration
+		return
+	}
+
+	// No certificate found - issue one.
+	cert, key, err = c.issuer.Issue(ctx, c.template, kv)
+	if err != nil {
+		err = fmt.Errorf("failed to issue: %w", err)
+		return
+	}
+
+	// Save to etcd in transaction. This ensures that no partial writes happen, and that we haven't been raced to the
+	// save.
+	res, err := kv.Txn(ctx).
+		If(
+			clientv3.Compare(clientv3.CreateRevision(certPath), "=", 0),
+			clientv3.Compare(clientv3.CreateRevision(keyPath), "=", 0),
+		).
+		Then(
+			clientv3.OpPut(certPath, string(cert)),
+			clientv3.OpPut(keyPath, string(key)),
+		).Commit()
+	if err != nil {
+		err = fmt.Errorf("failed to write newly issued certificate: %w", err)
+	} else if !res.Succeeded {
+		err = fmt.Errorf("certificate issuance transaction failed: concurrent write")
+	}
+
+	return
+}
+
+// Ensure returns an x509 DER-encoded (but not PEM-encoded) certificate and key for a given Certificate.
+// If the certificate is volatile, each call to Ensure will cause a new certificate to be generated.
+// Otherwise, it will be retrieved from etcd, or generated and stored there if needed.
+func (c *Certificate) Ensure(ctx context.Context, kv clientv3.KV) (cert, key []byte, err error) {
+	cert, key, err = c.ensure(ctx, kv)
+	if err != nil {
+		return nil, nil, err
+	}
+	key, err = x509.MarshalPKCS8PrivateKey(ed25519.PrivateKey(key))
+	if err != nil {
+		err = fmt.Errorf("could not marshal private key (data corruption?): %w", err)
+		return
+	}
+	return cert, key, err
+}
diff --git a/metropolis/node/kubernetes/pki/kubernetes.go b/metropolis/node/kubernetes/pki/kubernetes.go
new file mode 100644
index 0000000..c4827a9
--- /dev/null
+++ b/metropolis/node/kubernetes/pki/kubernetes.go
@@ -0,0 +1,228 @@
+// Copyright 2020 The Monogon Project Authors.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package pki
+
+import (
+	"context"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"fmt"
+	"net"
+
+	"go.etcd.io/etcd/clientv3"
+	"k8s.io/client-go/tools/clientcmd"
+	configapi "k8s.io/client-go/tools/clientcmd/api"
+
+	common "git.monogon.dev/source/nexantic.git/metropolis/node"
+	"git.monogon.dev/source/nexantic.git/metropolis/node/core/logtree"
+)
+
+// KubeCertificateName is an enum-like unique name of a static Kubernetes certificate. The value of the name is used
+// as the unique part of an etcd path where the certificate and key are stored.
+type KubeCertificateName string
+
+const (
+	// The main Kubernetes CA, used to authenticate API consumers, and servers.
+	IdCA KubeCertificateName = "id-ca"
+
+	// Kubernetes apiserver server certificate.
+	APIServer KubeCertificateName = "apiserver"
+
+	// Kubelet client certificate, used to authenticate to the apiserver.
+	KubeletClient KubeCertificateName = "kubelet-client"
+
+	// Kubernetes Controller manager client certificate, used to authenticate to the apiserver.
+	ControllerManagerClient KubeCertificateName = "controller-manager-client"
+	// Kubernetes Controller manager server certificate, used to run its HTTP server.
+	ControllerManager KubeCertificateName = "controller-manager"
+
+	// Kubernetes Scheduler client certificate, used to authenticate to the apiserver.
+	SchedulerClient KubeCertificateName = "scheduler-client"
+	// Kubernetes scheduler server certificate, used to run its HTTP server.
+	Scheduler KubeCertificateName = "scheduler"
+
+	// Root-on-kube (system:masters) client certificate. Used to control the apiserver (and resources) by Smalltown
+	// internally.
+	Master KubeCertificateName = "master"
+
+	// OpenAPI Kubernetes Aggregation CA.
+	// See: https://kubernetes.io/docs/tasks/extend-kubernetes/configure-aggregation-layer/#ca-reusage-and-conflicts
+	AggregationCA    KubeCertificateName = "aggregation-ca"
+	FrontProxyClient KubeCertificateName = "front-proxy-client"
+)
+
+const (
+	// serviceAccountKeyName is the etcd path part that is used to store the ServiceAccount authentication secret.
+	// This is not a certificate, just an RSA key.
+	serviceAccountKeyName = "service-account-privkey"
+)
+
+// KubernetesPKI manages all PKI resources required to run Kubernetes on Smalltown. It contains all static certificates,
+// which can be retrieved, or be used to generate Kubeconfigs from.
+type KubernetesPKI struct {
+	logger       logtree.LeveledLogger
+	KV           clientv3.KV
+	Certificates map[KubeCertificateName]*Certificate
+}
+
+func NewKubernetes(l logtree.LeveledLogger, kv clientv3.KV) *KubernetesPKI {
+	pki := KubernetesPKI{
+		logger:       l,
+		KV:           kv,
+		Certificates: make(map[KubeCertificateName]*Certificate),
+	}
+
+	make := func(i, name KubeCertificateName, template x509.Certificate) {
+		pki.Certificates[name] = New(pki.Certificates[i], string(name), template)
+	}
+
+	pki.Certificates[IdCA] = New(SelfSigned, string(IdCA), CA("Smalltown Kubernetes ID CA"))
+	make(IdCA, APIServer, Server(
+		[]string{
+			"kubernetes",
+			"kubernetes.default",
+			"kubernetes.default.svc",
+			"kubernetes.default.svc.cluster",
+			"kubernetes.default.svc.cluster.local",
+			"localhost",
+		},
+		[]net.IP{{10, 0, 255, 1}, {127, 0, 0, 1}}, // TODO(q3k): add service network internal apiserver address
+	))
+	make(IdCA, KubeletClient, Client("smalltown:apiserver-kubelet-client", nil))
+	make(IdCA, ControllerManagerClient, Client("system:kube-controller-manager", nil))
+	make(IdCA, ControllerManager, Server([]string{"kube-controller-manager.local"}, nil))
+	make(IdCA, SchedulerClient, Client("system:kube-scheduler", nil))
+	make(IdCA, Scheduler, Server([]string{"kube-scheduler.local"}, nil))
+	make(IdCA, Master, Client("smalltown:master", []string{"system:masters"}))
+
+	pki.Certificates[AggregationCA] = New(SelfSigned, string(AggregationCA), CA("Smalltown OpenAPI Aggregation CA"))
+	make(AggregationCA, FrontProxyClient, Client("front-proxy-client", nil))
+
+	return &pki
+}
+
+// EnsureAll ensures that all static certificates (and the serviceaccount key) are present on etcd.
+func (k *KubernetesPKI) EnsureAll(ctx context.Context) error {
+	for n, v := range k.Certificates {
+		k.logger.Infof("Ensuring %s exists", string(n))
+		_, _, err := v.Ensure(ctx, k.KV)
+		if err != nil {
+			return fmt.Errorf("could not ensure certificate %q exists: %w", n, err)
+		}
+	}
+	_, err := k.ServiceAccountKey(ctx)
+	if err != nil {
+		return fmt.Errorf("could not ensure service account key exists: %w", err)
+	}
+	return nil
+}
+
+// Kubeconfig generates a kubeconfig blob for a given certificate name. The same lifetime semantics as in .Certificate
+// apply.
+func (k *KubernetesPKI) Kubeconfig(ctx context.Context, name KubeCertificateName) ([]byte, error) {
+	c, ok := k.Certificates[name]
+	if !ok {
+		return nil, fmt.Errorf("no certificate %q", name)
+	}
+	return c.Kubeconfig(ctx, k.KV)
+}
+
+// Certificate retrieves an x509 DER-encoded (but not PEM-wrapped) key and certificate for a given certificate name.
+// If the requested certificate is volatile, it will be created on demand. Otherwise it will be created on etcd (if not
+// present), and retrieved from there.
+func (k *KubernetesPKI) Certificate(ctx context.Context, name KubeCertificateName) (cert, key []byte, err error) {
+	c, ok := k.Certificates[name]
+	if !ok {
+		return nil, nil, fmt.Errorf("no certificate %q", name)
+	}
+	return c.Ensure(ctx, k.KV)
+}
+
+// Kubeconfig generates a kubeconfig blob for this certificate. The same lifetime semantics as in .Ensure apply.
+func (c *Certificate) Kubeconfig(ctx context.Context, kv clientv3.KV) ([]byte, error) {
+
+	cert, key, err := c.Ensure(ctx, kv)
+	if err != nil {
+		return nil, fmt.Errorf("could not ensure certificate exists: %w", err)
+	}
+
+	kubeconfig := configapi.NewConfig()
+
+	cluster := configapi.NewCluster()
+	cluster.Server = fmt.Sprintf("https://127.0.0.1:%v", common.KubernetesAPIPort)
+
+	ca, err := c.issuer.CACertificate(ctx, kv)
+	if err != nil {
+		return nil, fmt.Errorf("could not get CA certificate: %w", err)
+	}
+	if ca != nil {
+		cluster.CertificateAuthorityData = pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: ca})
+	}
+	kubeconfig.Clusters["default"] = cluster
+
+	authInfo := configapi.NewAuthInfo()
+	authInfo.ClientCertificateData = pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: cert})
+	authInfo.ClientKeyData = pem.EncodeToMemory(&pem.Block{Type: "PRIVATE KEY", Bytes: key})
+	kubeconfig.AuthInfos["default"] = authInfo
+
+	ct := configapi.NewContext()
+	ct.Cluster = "default"
+	ct.AuthInfo = "default"
+	kubeconfig.Contexts["default"] = ct
+
+	kubeconfig.CurrentContext = "default"
+	return clientcmd.Write(*kubeconfig)
+}
+
+// ServiceAccountKey retrieves (and possible generates and stores on etcd) the Kubernetes service account key. The
+// returned data is ready to be used by Kubernetes components (in PKIX form).
+func (k *KubernetesPKI) ServiceAccountKey(ctx context.Context) ([]byte, error) {
+	// TODO(q3k): this should be abstracted away once we abstract away etcd access into a library with try-or-create
+	// semantics.
+
+	path := etcdPath("%s.der", serviceAccountKeyName)
+
+	// Try loading  key from etcd.
+	keyRes, err := k.KV.Get(ctx, path)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get key from etcd: %w", err)
+	}
+
+	if len(keyRes.Kvs) == 1 {
+		// Certificate and key exists in etcd, return that.
+		return keyRes.Kvs[0].Value, nil
+	}
+
+	// No key found - generate one.
+	keyRaw, err := rsa.GenerateKey(rand.Reader, 2048)
+	if err != nil {
+		panic(err)
+	}
+	key, err := x509.MarshalPKCS8PrivateKey(keyRaw)
+	if err != nil {
+		panic(err) // Always a programmer error
+	}
+
+	// Save to etcd.
+	_, err = k.KV.Put(ctx, path, string(key))
+	if err != nil {
+		err = fmt.Errorf("failed to write newly generated key: %w", err)
+	}
+	return key, nil
+}