diff --git a/cluster/clustercfg/certs/generator.go b/cluster/clustercfg/certs/generator.go
new file mode 100644
index 0000000..7cd2c81
--- /dev/null
+++ b/cluster/clustercfg/certs/generator.go
@@ -0,0 +1,297 @@
+package certs
+
+import (
+	"bytes"
+	"crypto"
+	"crypto/ed25519"
+	"crypto/rand"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"log"
+	"math/big"
+	"net"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+// Certificate is a higher-level descriptor of an intent to generate a
+// certificate and corresponding Ed25519 keypair on disk.
+type Certificate struct {
+	// uniquer name for this cert, used to calculate filesystem paths.
+	name string
+	// root directory where all certs are stored.
+	root string
+	// duration used to determine TimeAfter. If not set, the certificate will
+	// never expire.
+	duration time.Duration
+
+	kind certificateKind
+
+	// cn is the subject common name that's going to be produced in the X.509
+	// certificate.
+	cn string
+	// o is the subject organziation that's going to be produced in the X.509
+	// certificate.
+	o string
+	// san are the DNS alternate names that are going to be produced in the
+	// X.509 certificate.
+	san []string
+	// ips are the IP alternate names that are going to be produced in the
+	// X.509 certificate.
+	ips []net.IP
+
+	// issuer, if set, is the certificate that will sign this certificate. If
+	// not set, the certificate will be self-signed.
+	issuer *Certificate
+}
+
+// Paths returns local filesystem paths to the CA certificate, certificate and
+// key respectively. If the certificate is self signed, the CA path returned
+// will be empty. These files might or might not live on the file system - you
+// should first call Ensure to make sure they do.
+func (c *Certificate) Paths() (caPath, certPath, keyPath string) {
+	if c.issuer != nil {
+		caPath = c.issuer.path(fileKindCert)
+	}
+	certPath = c.path(fileKindCert)
+	keyPath = c.path(fileKindKey)
+	return
+}
+
+type certificateKind string
+
+const (
+	kindServer       certificateKind = "server"
+	kindClient       certificateKind = "client"
+	kindClientServer certificateKind = "client-server"
+	kindCA           certificateKind = "ca"
+	kindProdvider    certificateKind = "prodvider"
+)
+
+type fileKind string
+
+const (
+	fileKindKey          fileKind = "key"
+	fileKindKeyEncrypted fileKind = "key-encrypted"
+	fileKindCert         fileKind = "cert"
+)
+
+// path returns the path to the generated fileKind for this Certificate.
+func (c *Certificate) path(k fileKind) string {
+	switch k {
+	case fileKindKeyEncrypted:
+		return filepath.Join(c.root, "secrets", "cipher", c.name+".key")
+	case fileKindKey:
+		return filepath.Join(c.root, "secrets", "plain", c.name+".key")
+	case fileKindCert:
+		// clustercfg.py compat: CA certs end in .crt, non-CA certs end in .cert.
+		// We're keeping this accidental convention to avoid spurious nix rebuilds
+		// when migrating.
+		//
+		// Feel free to fix it if it annoys you.
+		extension := ".cert"
+		if c.kind == kindCA {
+			extension = ".crt"
+		}
+		return filepath.Join(c.root, "certs", c.name+extension)
+	default:
+		panic("unexpected file kind type " + k)
+	}
+}
+
+// ensureKey loads or generates-then-saves the private key for this
+// Certificate.
+func (c *Certificate) ensureKey() (crypto.Signer, error) {
+	path := c.path(fileKindKey)
+	_, err := os.Stat(path)
+	switch {
+	case err == nil:
+		return c.loadKey()
+	case errors.Is(err, os.ErrNotExist):
+		epath := c.path(fileKindKeyEncrypted)
+		if _, err = os.Stat(epath); err == nil {
+			return nil, fmt.Errorf("plaintext key at %q not found, but exists encrypted at %q - please decrypt using secretstore", path, epath)
+		}
+		return c.generateKey()
+	default:
+		return nil, fmt.Errorf("could not read key: %w", err)
+	}
+}
+
+func (c *Certificate) loadKey() (crypto.Signer, error) {
+	path := c.path(fileKindKey)
+	bytes, err := os.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	block, _ := pem.Decode(bytes)
+	if block == nil {
+		return nil, fmt.Errorf("no PEM block found")
+	}
+	if block.Type != "PRIVATE KEY" {
+		return nil, fmt.Errorf("unexpected PEM block: %q", block.Type)
+	}
+	key, err := x509.ParsePKCS8PrivateKey(block.Bytes)
+	if err != nil {
+		return nil, err
+	}
+	if k, ok := key.(ed25519.PrivateKey); ok {
+		return k, nil
+	}
+	return nil, fmt.Errorf("not an ED25519 key")
+}
+
+func (c *Certificate) generateKey() (crypto.Signer, error) {
+	_, priv, err := ed25519.GenerateKey(rand.Reader)
+	if err != nil {
+		return nil, err
+	}
+
+	pkcs8, err := x509.MarshalPKCS8PrivateKey(priv)
+	if err != nil {
+		return nil, err
+	}
+
+	block := pem.EncodeToMemory(&pem.Block{Type: "PRIVATE KEY", Bytes: pkcs8})
+	path := c.path(fileKindKey)
+	os.MkdirAll(filepath.Dir(path), 0700)
+	log.Printf("Saving %s key to %s ...", c.name, path)
+	if err := os.WriteFile(path, block, 0600); err != nil {
+		return nil, err
+	}
+
+	return priv, nil
+}
+
+// ensureCert loads or generates-then-saves the X.509 certificate for the
+// Certificate.
+func (c *Certificate) ensureCert() (*x509.Certificate, error) {
+	path := c.path(fileKindCert)
+	_, err := os.Stat(path)
+	switch {
+	case err == nil:
+		cert, err := c.loadCert()
+		switch err {
+		case nil:
+			return cert, nil
+		case errExpired:
+			return c.generateCert()
+		default:
+			return nil, err
+		}
+	case errors.Is(err, os.ErrNotExist):
+		return c.generateCert()
+	default:
+		return nil, fmt.Errorf("could not read cert: %w", err)
+	}
+}
+
+func (c *Certificate) generateCert() (*x509.Certificate, error) {
+	serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 127)
+	serialNumber, err := rand.Int(rand.Reader, serialNumberLimit)
+	if err != nil {
+		return nil, err
+	}
+
+	notAfter := unknownNotAfter
+	if c.duration != 0 {
+		notAfter = time.Now().Add(c.duration)
+	}
+	template := c.template()
+	template.SerialNumber = serialNumber
+	template.NotBefore = time.Now()
+	template.NotAfter = notAfter
+
+	parent := template
+	skey, err := c.ensureKey()
+	if err != nil {
+		return nil, fmt.Errorf("when ensuring key: %w", err)
+	}
+	pkey := skey.Public()
+	caskey := skey
+	if c.issuer != nil {
+		caskey, err = c.issuer.ensureKey()
+		if err != nil {
+			return nil, fmt.Errorf("when ensuring CA key: %w", err)
+		}
+		cacert, err := c.issuer.ensureCert()
+		if err != nil {
+			return nil, fmt.Errorf("when ensuring CA cert: %w", err)
+		}
+		parent = cacert
+	}
+
+	bytes, err := x509.CreateCertificate(rand.Reader, template, parent, pkey, caskey)
+	if err != nil {
+		return nil, fmt.Errorf("issuing certificate failed: %w", err)
+	}
+
+	block := pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: bytes})
+	path := c.path(fileKindCert)
+	os.MkdirAll(filepath.Dir(path), 0700)
+	log.Printf("Saving %s cert to %s ...", c.name, path)
+	if err := os.WriteFile(path, block, 0600); err != nil {
+		return nil, err
+	}
+
+	return x509.ParseCertificate(bytes)
+}
+
+// errExpired is returned if the cert exists on disk but has (nearly) expired.
+var errExpired = errors.New("certificate expired")
+
+func (c *Certificate) loadCert() (*x509.Certificate, error) {
+	path := c.path(fileKindCert)
+	b, err := os.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+
+	block, _ := pem.Decode(b)
+	if block == nil {
+		return nil, fmt.Errorf("no PEM block found")
+	}
+	if block.Type != "CERTIFICATE" {
+		return nil, fmt.Errorf("unexpected PEM block: %q", block.Type)
+	}
+	cert, err := x509.ParseCertificate(block.Bytes)
+	if err != nil {
+		return nil, err
+	}
+	if time.Now().Add(time.Hour).After(cert.NotAfter) {
+		return nil, errExpired
+	}
+	pkey, ok := cert.PublicKey.(ed25519.PublicKey)
+	if !ok {
+		return nil, fmt.Errorf("not a ED25519 cert")
+	}
+	skey, err := c.ensureKey()
+	if err != nil {
+		return nil, fmt.Errorf("when ensuring key: %w", err)
+	}
+	if !bytes.Equal(pkey, skey.Public().(ed25519.PublicKey)) {
+		return nil, fmt.Errorf("issued for different key")
+	}
+
+	template := c.template()
+	if err := compareCertData(template, cert); err != nil {
+		return nil, err
+	}
+	return cert, nil
+}
+
+// Ensure makes sure the given Certificate (and all of its' issuers) have
+// corresponding private keys and X.509 certificates on disk, generating things
+// as necessary.
+func (c *Certificate) Ensure() error {
+	cert, err := c.ensureCert()
+	if err != nil {
+		return fmt.Errorf("when ensuring cert %s: %w", c.name, err)
+	}
+	_ = cert
+
+	return nil
+}