diff --git a/cluster/clustercfg/BUILD b/cluster/clustercfg/BUILD
index e207c4d..e7b308e 100644
--- a/cluster/clustercfg/BUILD
+++ b/cluster/clustercfg/BUILD
@@ -1,19 +1,25 @@
-load("@pydeps//:requirements.bzl", "requirement")
+load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library")
 
-py_binary(
-    name = "clustercfg",
-    python_version = "PY3",
+go_library(
+    name = "go_default_library",
     srcs = [
-        "clustercfg.py",
-        "ca.py",
+        "cmd_admincreds.go",
+        "cmd_gencerts.go",
+        "main.go",
     ],
-    visibility = ["//visibility:public"],
+    importpath = "code.hackerspace.pl/hscloud/cluster/clustercfg",
+    visibility = ["//visibility:private"],
     deps = [
-        requirement("cffi"),
-        requirement("fabric"),
-        requirement("idna"),
-        requirement("six"),
-        "//tools:secretstore_lib",
-        "//tools/hscloud:python",
+        "//cluster/clustercfg/certs:go_default_library",
+        "//go/workspace:go_default_library",
+        "@com_github_spf13_cobra//:go_default_library",
+        "@io_k8s_client_go//tools/clientcmd:go_default_library",
+        "@io_k8s_client_go//tools/clientcmd/api:go_default_library",
     ],
 )
+
+go_binary(
+    name = "clustercfg",
+    embed = [":go_default_library"],
+    visibility = ["//visibility:public"],
+)
diff --git a/cluster/clustercfg/ca.py b/cluster/clustercfg/ca.py
deleted file mode 100644
index 0107080..0000000
--- a/cluster/clustercfg/ca.py
+++ /dev/null
@@ -1,315 +0,0 @@
-# encoding: utf-8
-from datetime import datetime, timezone
-import json
-import logging
-import os
-from six import StringIO
-import subprocess
-import tempfile
-
-
-logger = logging.getLogger(__name__)
-
-
-_std_subj = {
-    "C": "PL",
-    "ST": "Mazowieckie",
-    "L": "Warsaw",
-    "O": "Warsaw Hackerspace",
-    "OU": "clustercfg",
-}
-
-_ca_csr = {
-  "CN": "Prototype Test Certificate Authority",
-  "key": {
-    "algo": "rsa",
-    "size": 2048
-  },
-  "names": [ _std_subj ],
-}
-
-_ca_config = {
-  "signing": {
-    "default": {
-      "expiry": "168h"
-    },
-    "profiles": {
-      "intermediate": {
-        "expiry": "8760h",
-        "usages": [
-          "signing",
-          "key encipherment",
-          "cert sign",
-          "crl sign",
-          "server auth",
-          "client auth",
-        ],
-        "ca_constraint": {
-          "is_ca": True,
-        },
-      },
-      "server": {
-        "expiry": "8760h",
-        "usages": [
-          "signing",
-          "key encipherment",
-          "server auth"
-        ]
-      },
-      "client": {
-        "expiry": "8760h",
-        "usages": [
-          "signing",
-          "key encipherment",
-          "client auth"
-        ]
-      },
-      "client-server": {
-        "expiry": "8760h",
-        "usages": [
-          "signing",
-          "key encipherment",
-          "server auth",
-          "client auth"
-        ]
-      }
-    }
-  }
-}
-
-
-class CAException(Exception):
-    pass
-
-
-class CA(object):
-    def __init__(self, secretstore, certdir, short, cn):
-        self.ss = secretstore
-        self.cdir = certdir
-        self.short = short
-        self.cn = cn
-        self._init_ca()
-
-    def __str__(self):
-        return 'CN={} ({})'.format(self.cn, self.short)
-
-    @property
-    def _secret_key(self):
-        return 'ca-{}.key'.format(self.short)
-
-    @property
-    def _cert(self):
-        return os.path.join(self.cdir, 'ca-{}.crt'.format(self.short))
-
-    @property
-    def cert_data(self):
-        with open(self._cert) as f:
-            return f.read()
-
-    def _cfssl_call(self, args, obj=None, stdin=None):
-        p = subprocess.Popen(['cfssl'] + args,
-                             stdin=subprocess.PIPE, stdout=subprocess.PIPE,
-                             stderr=subprocess.PIPE)
-        if obj is not None:
-            stdin = json.dumps(obj)
-
-        outs, errs = p.communicate(stdin.encode())
-        if p.returncode != 0:
-            raise Exception(
-                'cfssl failed. stderr: %r, stdout: %r, code: %r' % (
-                    errs, outs, p.returncode))
-
-        out = json.loads(outs)
-        return out
-
-    def _init_ca(self):
-        if self.ss.exists(self._secret_key):
-            return
-
-        ca_csr = dict(_ca_csr)
-        ca_csr['CN'] = self.cn
-
-        logger.info("{}: Generating CA...".format(self))
-        out = self._cfssl_call(['gencert', '-initca', '-'], obj=ca_csr)
-
-        f = self.ss.open(self._secret_key, 'w')
-        f.write(out['key'])
-        f.close()
-
-        f = open(self._cert, 'w')
-        f.write(out['cert'])
-        f.close()
-
-    def gen_key(self, hosts, o=_std_subj['O'], ou=_std_subj['OU'], save=None):
-        """お元気ですか？"""
-        cfg = {
-            "CN": hosts[0],
-            "hosts": hosts,
-            "key": {
-                "algo": "rsa",
-                "size": 4096,
-            },
-            "names": [
-                {
-                    "C": _std_subj["C"],
-                    "ST": _std_subj["ST"],
-                    "L": _std_subj["L"],
-                    "O": o,
-                    "OU": ou,
-                },
-            ],
-        }
-        cfg.update(_ca_config)
-        logger.info("{}: Generating key/CSR for {}".format(self, hosts))
-        out = self._cfssl_call(['genkey', '-'], obj=cfg)
-
-        key, csr = out['key'], out['csr']
-        if save is not None:
-            logging.info("{}: Saving new key to secret {}".format(self, save))
-            f = self.ss.open(save, 'w')
-            f.write(key)
-            f.close()
-
-        return key, csr
-
-    def gen_csr(self, key, hosts, o=_std_subj['O'], ou=_std_subj['OU']):
-        """
-        Generate a CSR while already having a private key - for renewals, etc.
-
-        TODO(q3k): this shouldn't be a CA method, but a cert method.
-        """
-        cfg = {
-            "CN": hosts[0],
-            "hosts": hosts,
-            "key": {
-                "algo": "rsa",
-                "size": 4096,
-            },
-            "names": [
-                {
-                    "C": _std_subj["C"],
-                    "ST": _std_subj["ST"],
-                    "L": _std_subj["L"],
-                    "O": o,
-                    "OU": ou,
-                },
-            ],
-        }
-        cfg.update(_ca_config)
-        logger.info("{}: Generating CSR for {}".format(self, hosts))
-        out = self._cfssl_call(['gencsr', '-key', key, '-'], obj=cfg)
-
-        return out['csr']
-
-    def sign(self, csr, save=None, profile='client-server'):
-        logging.info("{}: Signing CSR".format(self))
-        ca = self._cert
-        cakey = self.ss.plaintext(self._secret_key)
-
-        config = tempfile.NamedTemporaryFile(mode='w')
-        json.dump(_ca_config, config)
-        config.flush()
-
-        out = self._cfssl_call(['sign', '-ca=' + ca, '-ca-key=' + cakey,
-                                '-profile='+profile, '-config='+config.name, '-'], stdin=csr)
-        cert = out['cert']
-        if save is not None:
-            name = os.path.join(self.cdir, save)
-            logging.info("{}: Saving new certificate to {}".format(self, name))
-            f = open(name, 'w')
-            f.write(cert)
-            f.close()
-
-        config.close()
-        return cert
-
-    def upload(self, c, remote_cert):
-        logger.info("Uploading CA {} to {}".format(self, remote_cert))
-        c.put(local=self._cert, remote=remote_cert)
-
-    def make_cert(self, *a, **kw):
-        return ManagedCertificate(self, *a, **kw)
-
-
-class ManagedCertificate(object):
-    def __init__(self, ca, name, hosts, o=None, ou=None, profile='client-server'):
-        self.ca = ca
-
-        self.hosts = hosts
-        self.name = name
-        self.key = '{}.key'.format(name)
-        self.cert = '{}.cert'.format(name)
-        self.o = o
-        self.ou = ou
-        self.profile = profile
-
-        self.ensure()
-
-    def __str__(self):
-        return '{}'.format(self.name)
-
-    @property
-    def key_exists(self):
-        return self.ca.ss.exists(self.key)
-
-    @property
-    def key_data(self):
-        f = open(self.ca.ss.open(self.key))
-        d = f.read()
-        f.close()
-        return d
-
-    @property
-    def key_path(self):
-        return self.ca.ss.plaintext(self.key)
-
-    @property
-    def cert_path(self):
-        return os.path.join(self.ca.cdir, self.cert)
-
-    @property
-    def cert_exists(self):
-        return os.path.exists(self.cert_path)
-
-    @property
-    def cert_data(self):
-        with open(self.cert_path) as f:
-            return f.read()
-
-    @property
-    def cert_expires_soon(self):
-        if not self.cert_exists:
-            return False
-
-        out = self.ca._cfssl_call(['certinfo', '-cert', self.cert_path], stdin="")
-        not_after = datetime.strptime(out['not_after'], '%Y-%m-%dT%H:%M:%SZ').replace(tzinfo=timezone.utc)
-        until = not_after - datetime.now(timezone.utc)
-        if until.days < 30:
-            return True
-        return False
-
-    def ensure(self):
-        if self.key_exists and self.cert_exists and not self.cert_expires_soon:
-            return
-
-        key = None
-        if not self.key_exists:
-            logger.info("{}: Generating key...".format(self))
-            key, csr = self.ca.gen_key(self.hosts, o=self.o, ou=self.ou, save=self.key)
-        else:
-            logger.info("{}: Renewing certificate...".format(self))
-            # Use already existing key
-            csr = self.ca.gen_csr(self.key_path, self.hosts, o=self.o, ou=self.ou)
-        self.ca.sign(csr, save=self.cert, profile=self.profile)
-
-    def upload(self, c, remote_cert, remote_key, concat_ca=False):
-        logger.info("Uploading Cert {} to {} & {}".format(self, remote_cert, remote_key))
-        if concat_ca:
-            f = StringIO(self.cert_data + self.ca.cert_data)
-            c.put(local=f, remote=remote_cert)
-        else:
-            c.put(local=self.cert_path, remote=remote_cert)
-        c.put(local=self.key_path, remote=remote_key)
-
-    def upload_pki(self, c, pki, concat_ca=False):
-        self.upload(c, pki['cert'], pki['key'], concat_ca)
diff --git a/cluster/clustercfg/certs/BUILD.bazel b/cluster/clustercfg/certs/BUILD.bazel
new file mode 100644
index 0000000..c115680
--- /dev/null
+++ b/cluster/clustercfg/certs/BUILD.bazel
@@ -0,0 +1,12 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "certs.go",
+        "generator.go",
+        "x509.go",
+    ],
+    importpath = "code.hackerspace.pl/hscloud/cluster/clustercfg/certs",
+    visibility = ["//visibility:public"],
+)
diff --git a/cluster/clustercfg/certs/certs.go b/cluster/clustercfg/certs/certs.go
new file mode 100644
index 0000000..7571717
--- /dev/null
+++ b/cluster/clustercfg/certs/certs.go
@@ -0,0 +1,288 @@
+package certs
+
+import (
+	"net"
+	"time"
+)
+
+// Certificates is the set of certificates required to run our Kubernetes
+// production.
+type Certificates struct {
+	CAs CAs
+
+	ProdviderIntermediateCA *Certificate
+
+	Global  Global
+	PerNode map[string]PerNode
+}
+
+type ensurer interface {
+	Ensure() error
+}
+
+// Ensure checks that all the Kubernetes production certificates and keys are
+// present on disk, generating them as necessary.
+//
+// If the user has not decrypted cluster/secrets, an error will be returned.
+// However, deeper sync checks are not currently performed.
+func (c *Certificates) Ensure() error {
+	sub := []ensurer{
+		&c.CAs,
+		c.ProdviderIntermediateCA,
+		&c.Global,
+	}
+	for _, pn := range c.PerNode {
+		sub = append(sub, &pn)
+	}
+	for _, s := range sub {
+		if err := s.Ensure(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// CAs are the root certificate authorities we use.
+type CAs struct {
+	// EtcdPeer is used by etcd member nodes to authenticate peers.
+	EtcdPeer *Certificate
+	// Etcd is used by etcd membrer nodes to authenticate clients (ie.
+	// kube-apiservers).
+	Etcd *Certificate
+	// Kube is the main Kubernetes 'identity' CA, used to identify components
+	// and users.
+	Kube *Certificate
+	// KubeFront is the proxy/aggregation CA used by external apiservices to
+	// authenticate incoming apiserver connections.
+	KubeFront *Certificate
+	// Admitomatic is the CA used by the admitomatic webhook to authenticate
+	// incoming apiserver connections.
+	Admitomatic *Certificate
+}
+
+func (c *CAs) Ensure() error {
+	sub := []ensurer{
+		c.EtcdPeer,
+		c.Etcd,
+		c.Kube,
+		c.KubeFront,
+		c.Admitomatic,
+	}
+	for _, s := range sub {
+		if err := s.Ensure(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Global are all the non-per-node certificates we use.
+type Global struct {
+	// EtcdKube is used by kubernetes apiservers to authenticate to etcd
+	// members.
+	EtcdKube *Certificate
+
+	// KubeApiserver is used by kubernetes apiservers to authenticate to other
+	// kubernetes components/users.
+	KubeApiserver *Certificate
+	// KubeControllerManager is used by kubernetes controller managers to
+	// authenticate to the kubernetes apiservers.
+	KubeControllerManager *Certificate
+	// KubeScheduler is used by the kubernetes schedulers to authenticate to
+	// the kubernetes apiservers.
+	KubeScheduler *Certificate
+
+	// KubefrontApiserver is used by the kubernetes apiserver to authenticate
+	// to external apiservices.
+	KubefrontApiserver *Certificate
+
+	// AdmitomaticWebhook is used by the admitomatic webhook to authenticate to
+	// the Kubernetes apiservers.
+	AdmitomaticWebhook *Certificate
+}
+
+func (g *Global) Ensure() error {
+	sub := []ensurer{
+		g.EtcdKube,
+		g.KubeApiserver,
+		g.KubeControllerManager,
+		g.KubeScheduler,
+		g.KubefrontApiserver,
+		g.AdmitomaticWebhook,
+	}
+	for _, s := range sub {
+		if err := s.Ensure(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (c *Certificates) MakeKubeEmergencyCreds(root, breadcrumb string) *Certificate {
+	return &Certificate{
+		name:     "emergency",
+		duration: 7 * 24 * time.Hour,
+		root:     root,
+		kind:     kindClient,
+		cn:       "admin",
+		san:      []string{"admin", breadcrumb},
+		o:        "system:masters",
+		issuer:   c.CAs.Kube,
+	}
+}
+
+// Per node are all the per-node certificates we use.
+type PerNode struct {
+	// EtcdPeer is used by etcd members to authenticate to other etcd members.
+	EtcdPeer *Certificate
+	// EtcdClient is used by etcd members to authenticate to their clients.
+	EtcdClient *Certificate
+
+	// Kubelet is used by kubelets to authenticate to other kubernetes
+	// components.
+	Kubelet *Certificate
+}
+
+func (p *PerNode) Ensure() error {
+	sub := []ensurer{
+		p.EtcdPeer,
+		p.EtcdClient,
+		p.Kubelet,
+	}
+	for _, s := range sub {
+		if err := s.Ensure(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func mkCA(root, name, cn string) *Certificate {
+	return &Certificate{
+		name: name,
+		root: root,
+		kind: kindCA,
+		cn:   cn,
+	}
+}
+
+// Prepare builds our Certificates structure at a given location on the
+// filesystem, for the given nodes.
+//
+// Calling Ensure() on the returned Certificates will actually engage
+// generation logic. Before that, no disk accesses are performed.
+func Prepare(root string, fqdns []string) Certificates {
+	certs := Certificates{
+		CAs: CAs{
+			EtcdPeer:    mkCA(root, "ca-etcdpeer", "etcd peer ca"),
+			Etcd:        mkCA(root, "ca-etcd", "etcd ca"),
+			Kube:        mkCA(root, "ca-kube", "kubernetes main CA"),
+			KubeFront:   mkCA(root, "ca-kubefront", "kubernetes frontend CA"),
+			Admitomatic: mkCA(root, "ca-admitomatic", "admitomatic webhook CA"),
+		},
+		PerNode: make(map[string]PerNode),
+	}
+
+	certs.ProdviderIntermediateCA = &Certificate{
+		name:   "ca-kube-prodvider",
+		root:   root,
+		kind:   kindProdvider,
+		cn:     "kubernetes prodvider intermediate",
+		issuer: certs.CAs.Kube,
+	}
+	certs.Global = Global{
+		EtcdKube: &Certificate{
+			name:   "etcd-kube",
+			root:   root,
+			kind:   kindClient,
+			cn:     "kube etcd client certificate",
+			san:    []string{"kube"},
+			issuer: certs.CAs.Etcd,
+		},
+		KubeApiserver: &Certificate{
+			name: "kube-apiserver",
+			root: root,
+			kind: kindClientServer,
+			cn:   "k0.hswaw.net",
+			san: []string{
+				"k0.hswaw.net",
+				"kubernetes.default.svc.k0.hswaw.net",
+			},
+			ips: []net.IP{
+				{10, 10, 12, 1},
+			},
+			issuer: certs.CAs.Kube,
+		},
+		KubeControllerManager: &Certificate{
+			name:   "kube-controllermanager",
+			root:   root,
+			kind:   kindClientServer,
+			cn:     "system:kube-controller-manager",
+			san:    []string{"system:kube-controller-manager"},
+			o:      "system:kube-controller-manager",
+			issuer: certs.CAs.Kube,
+		},
+		KubeScheduler: &Certificate{
+			name:   "kube-scheduler",
+			root:   root,
+			kind:   kindClientServer,
+			cn:     "system:kube-scheduler",
+			san:    []string{"system:kube-scheduler"},
+			o:      "system:kube-scheduler",
+			issuer: certs.CAs.Kube,
+		},
+		KubefrontApiserver: &Certificate{
+			name:   "kubefront-apiserver",
+			root:   root,
+			kind:   kindClientServer,
+			cn:     "Kubernetes Frontend",
+			san:    []string{"apiserver"},
+			issuer: certs.CAs.KubeFront,
+		},
+		AdmitomaticWebhook: &Certificate{
+			name:   "admitomatic-webhook",
+			root:   root,
+			kind:   kindServer,
+			cn:     "Admitomatic Webhook",
+			san:    []string{"admitomatic.admitomatic.svc"},
+			issuer: certs.CAs.Admitomatic,
+		},
+	}
+	for _, fqdn := range fqdns {
+		certs.PerNode[fqdn] = PerNode{
+			EtcdPeer: &Certificate{
+				name:   "etcdpeer-" + fqdn,
+				root:   root,
+				kind:   kindClientServer,
+				cn:     "node etcd peer certificate",
+				san:    []string{fqdn},
+				issuer: certs.CAs.EtcdPeer,
+			},
+			EtcdClient: &Certificate{
+				name: "etcd-" + fqdn,
+				root: root,
+				// etcd seems to need client too, as it's connecting to itself
+				// for... some reason?
+				// https://github.com/etcd-io/etcd/issues/9785
+				kind:   kindClientServer,
+				cn:     "node etcd server certificate",
+				san:    []string{fqdn},
+				issuer: certs.CAs.Etcd,
+			},
+			Kubelet: &Certificate{
+				name: "kube-kubelet-" + fqdn,
+				root: root,
+				kind: kindClientServer,
+				cn:   "system:node:" + fqdn,
+				o:    "system:nodes",
+				san: []string{
+					"system:node:" + fqdn,
+					fqdn,
+				},
+				issuer: certs.CAs.Kube,
+			},
+		}
+	}
+
+	return certs
+}
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
+}
diff --git a/cluster/clustercfg/certs/x509.go b/cluster/clustercfg/certs/x509.go
new file mode 100644
index 0000000..a64ec1a
--- /dev/null
+++ b/cluster/clustercfg/certs/x509.go
@@ -0,0 +1,98 @@
+package certs
+
+import (
+	"bytes"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"fmt"
+	"strings"
+	"time"
+)
+
+var (
+	// From RFC 5280 Section 4.1.2.5
+	unknownNotAfter = time.Unix(253402300799, 0)
+)
+
+// compareCertData returns an error if any of the 'important' bits of the two
+// certificates differ. Those are the bits that we template ourselves, and that
+// are not issue-dependent (ie. not time or serial or kid or ...).
+func compareCertData(template, cert *x509.Certificate) error {
+	if want, got := template.Subject.String(), cert.Subject.String(); want != got {
+		return fmt.Errorf("issued for different subject, wanted %s, got %s", want, got)
+	}
+	if want, got := strings.Join(template.DNSNames, ","), strings.Join(cert.DNSNames, ","); want != got {
+		return fmt.Errorf("issued for different DNS names, wanted %s, got %s", want, got)
+	}
+	if want, got := len(template.IPAddresses), len(cert.IPAddresses); want != got {
+		return fmt.Errorf("issued for different IP addresses, wanted %v, got %v", want, got)
+	} else {
+		for i := 0; i < len(template.IPAddresses); i++ {
+			if want, got := template.IPAddresses[i], cert.IPAddresses[i]; !bytes.Equal(want, got) {
+				return fmt.Errorf("issued for different IP addresses, wanted %v, got %v", want, got)
+			}
+		}
+	}
+	if want, got := template.KeyUsage, cert.KeyUsage; want != got {
+		return fmt.Errorf("issued for different key usage, wanted %d, got %d", want, got)
+	}
+	if want, got := len(template.ExtKeyUsage), len(cert.ExtKeyUsage); want != got {
+		return fmt.Errorf("issued for different ext key usage, wanted %v, got %v", want, got)
+	} else {
+		for i := 0; i < len(template.ExtKeyUsage); i++ {
+			if want, got := template.ExtKeyUsage[i], cert.ExtKeyUsage[i]; want != got {
+				return fmt.Errorf("issued for different ext key usage, wanted %v, got %v", want, got)
+			}
+		}
+	}
+	if want, got := template.IsCA, cert.IsCA; want != got {
+		return fmt.Errorf("issued for different IsCA, wanted %v, got %v", want, got)
+	}
+	if want, got := template.BasicConstraintsValid, cert.BasicConstraintsValid; want != got {
+		return fmt.Errorf("issued for different basic constraints valid, wanted %v, got %v", want, got)
+	}
+	return nil
+}
+
+// template builds an x509 'template' certificate, ie. makes an
+// x509.Certificate with all the fields built up from the data contained in
+// Certificate, but without any per-issue fields like times, serial number,
+// etc.
+func (c *Certificate) template() *x509.Certificate {
+	template := &x509.Certificate{
+		Subject: pkix.Name{
+			CommonName: c.cn,
+		},
+		DNSNames:    c.san,
+		IPAddresses: c.ips,
+	}
+	if c.o != "" {
+		template.Subject.Organization = []string{c.o}
+	}
+	switch c.kind {
+	case kindServer:
+		template.KeyUsage = x509.KeyUsageDigitalSignature | x509.KeyUsageKeyEncipherment
+		template.ExtKeyUsage = []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth}
+		template.DNSNames = c.san
+	case kindClient:
+		template.KeyUsage = x509.KeyUsageDigitalSignature | x509.KeyUsageKeyEncipherment
+		template.ExtKeyUsage = []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth}
+		template.DNSNames = c.san
+	case kindClientServer:
+		template.KeyUsage = x509.KeyUsageDigitalSignature | x509.KeyUsageKeyEncipherment
+		template.ExtKeyUsage = []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth, x509.ExtKeyUsageServerAuth}
+	case kindCA:
+		template.IsCA = true
+		template.BasicConstraintsValid = true
+		template.KeyUsage = x509.KeyUsageCertSign | x509.KeyUsageCRLSign | x509.KeyUsageDigitalSignature
+		template.ExtKeyUsage = []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth, x509.ExtKeyUsageServerAuth, x509.ExtKeyUsageOCSPSigning}
+		template.AuthorityKeyId = template.SubjectKeyId
+	case kindProdvider:
+		template.IsCA = true
+		template.BasicConstraintsValid = true
+		template.KeyUsage = x509.KeyUsageCertSign | x509.KeyUsageCRLSign | x509.KeyUsageDigitalSignature | x509.KeyUsageKeyEncipherment
+		template.ExtKeyUsage = []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth, x509.ExtKeyUsageServerAuth, x509.ExtKeyUsageOCSPSigning}
+		template.AuthorityKeyId = template.SubjectKeyId
+	}
+	return template
+}
diff --git a/cluster/clustercfg/clustercfg.py b/cluster/clustercfg/clustercfg.py
deleted file mode 100644
index 30b87b8..0000000
--- a/cluster/clustercfg/clustercfg.py
+++ /dev/null
@@ -1,221 +0,0 @@
-#!/usr/bin/env python
-
-from builtins import object
-
-import datetime
-from io import BytesIO
-import json
-import logging
-import os
-import tempfile
-import subprocess
-import sys
-
-from cryptography import x509
-from cryptography.hazmat.backends import default_backend
-import fabric
-
-from tools import secretstore
-from tools.hscloud import lib as hscloud
-
-import ca
-
-
-local_root = hscloud.workspace_location()
-
-
-cluster = 'k0.hswaw.net'
-ss = secretstore.SecretStore(
-    plain_root=os.path.join(local_root, 'cluster/secrets/plain'),
-    cipher_root=os.path.join(local_root, 'cluster/secrets/cipher'))
-
-
-logger = logging.getLogger()
-logger.setLevel(logging.INFO)
-formatter = logging.Formatter('%(levelname)s - %(message)s')
-sh = logging.StreamHandler()
-sh.setFormatter(formatter)
-logger.addHandler(sh)
-
-
-def configure_k8s(username, ca, cert, key):
-    subprocess.check_call([
-        'kubectl', 'config',
-        'set-cluster', 'admin.' + cluster,
-        '--certificate-authority=' + ca,
-        '--embed-certs=true',
-        '--server=https://' + cluster + ':4001',
-    ])
-    subprocess.check_call([
-        'kubectl', 'config',
-        'set-credentials', username,
-        '--client-certificate=' + cert,
-        '--client-key=' + key,
-        '--embed-certs=true',
-    ])
-    subprocess.check_call([
-        'kubectl', 'config',
-        'set-context', 'admin.' + cluster,
-        '--cluster=' + 'admin.' + cluster,
-        '--user=' + username,
-    ])
-    subprocess.check_call([
-        'kubectl', 'config',
-        'use-context', 'admin.' + cluster,
-    ])
-
-
-def admincreds(args):
-    if len(args) != 1:
-        sys.stderr.write("Usage: admincreds q3k\n")
-        return 1
-    username = args[0]
-    print("")
-    print("WARNING WARNING WARNING WARNING WARNING WARNING")
-    print("===============================================")
-    print("")
-    print("You are requesting ADMIN credentials.")
-    print("")
-    print("You likely shouldn't be doing this, and")
-    print("instead should be using `prodaccess`.")
-    print("")
-    print("===============================================")
-    print("WARNING WARNING WARNING WARNING WARNING WARNING")
-    print("")
-
-    ## Make kube certificates.
-    certs_root = os.path.join(local_root, 'cluster/certs')
-    ca_kube = ca.CA(ss, certs_root, 'kube', 'kubernetes main CA')
-
-    local_key = os.path.join(local_root, '.kubectl/admin.key')
-    local_crt = os.path.join(local_root, '.kubectl/admin.crt')
-
-    kubectl = os.path.join(local_root, '.kubectl')
-    if not os.path.exists(kubectl):
-        os.mkdir(kubectl)
-
-    generate_cert = False
-    if not os.path.exists(local_key):
-        generate_cert = True
-
-    if os.path.exists(local_crt):
-        with open(local_crt, 'rb') as f:
-            b = f.read()
-            cert = x509.load_pem_x509_certificate(b, default_backend())
-            delta = cert.not_valid_after - datetime.datetime.now()
-            logger.info("admin: existing cert expiry: {}".format(delta))
-            if delta.total_seconds() < 3600 * 24:
-                logger.info("admin: expires soon, regenerating")
-                generate_cert = True
-    else:
-        generate_cert = True
-
-    if not generate_cert:
-        return configure_k8s(username, ca_kube._cert, local_crt, local_key)
-
-    key, csr = ca_kube.gen_key(hosts=['admin', username], o='system:masters', ou='Kube Admin Account')
-    crt = ca_kube.sign(csr)
-
-    with open(local_key, 'w') as f:
-        f.write(key)
-
-    with open(local_crt, 'w') as f:
-        f.write(crt)
-
-    configure_k8s(username, ca_kube._cert, local_crt, local_key)
-
-
-def nodestrap(args, nocerts=False):
-    if len(args) != 1:
-        sys.stderr.write("Usage: nodestrap bc01n01.hswaw.net\n")
-        return 1
-    fqdn = args[0]
-
-    logger.info("Nodestrapping {}...".format(fqdn))
-    r = fabric.Connection('root@{}'.format(fqdn))
-
-    if not nocerts:
-        certs_root = os.path.join(local_root, 'cluster/certs')
-
-        # Make etcd peer certificate for node.
-        ca_etcd_peer = ca.CA(ss, certs_root, 'etcdpeer', 'etcd peer ca')
-        ca_etcd_peer.make_cert('etcdpeer-{}'.format(fqdn), hosts=[fqdn], ou='node etcd peer certificate')
-
-        # Make etcd server certificate for node and client certificate for kube.
-        ca_etcd = ca.CA(ss, certs_root, 'etcd', 'etcd ca')
-
-        ca_etcd.make_cert('etcd-{}'.format(fqdn), hosts=[fqdn], ou='node etcd server certificate')
-
-        ca_etcd.make_cert('etcd-kube', hosts=['kube'], ou='kube etcd client certificate')
-
-        ca_etcd.make_cert('etcd-root', hosts=['root'], ou='root etcd client certificate')
-
-        ca_etcd.make_cert('etcd-calico', hosts=['calico'], ou='root etcd client certificate')
-
-        ## Make kube certificates.
-        ca_kube = ca.CA(ss, certs_root, 'kube', 'kubernetes main CA')
-
-        # Make prodvider intermediate CA.
-        ca_kube.make_cert('ca-kube-prodvider', o='Warsaw Hackerspace', ou='kubernetes prodvider intermediate', hosts=['kubernetes prodvider intermediate CA'], profile='intermediate').ensure()
-
-        # Make kubelet certificate (per node).
-        ca_kube.make_cert('kube-kubelet-'+fqdn, o='system:nodes', ou='Kubelet', hosts=['system:node:'+fqdn, fqdn])
-
-        # Make apiserver certificate.
-        ca_kube.make_cert('kube-apiserver', ou='Kubernetes API', hosts=[cluster, 'kubernetes.default.svc.'+cluster, '10.10.12.1'])
-
-        # Make service accounts decryption key (as cert for consistency).
-        ca_kube.make_cert('kube-serviceaccounts', ou='Kubernetes Service Accounts Signer', hosts=['serviceaccounts'])
-
-        # Make kube component certificates.
-        kube_components = ['controllermanager', 'scheduler', 'proxy']
-        for k in kube_components:
-            # meh 
-            if k == 'controllermanager':
-                o = 'system:kube-controller-manager'
-            else:
-                o = 'system:kube-'+k
-            ou = 'Kubernetes Component '+k
-            c = ca_kube.make_cert('kube-'+k, ou=ou, o=o, hosts=[o,])
-
-        ## Make kubefront certificates.
-        ca_kubefront = ca.CA(ss, certs_root, 'kubefront', 'kubernetes frontend CA')
-        ca_kubefront.make_cert('kubefront-apiserver', ou='Kubernetes Frontend', hosts=['apiserver'])
-
-        ## Make admitomatic (admission controller) certificates.
-        ca_admitomatic = ca.CA(ss, certs_root, 'admitomatic', 'admitomatic webhook CA')
-        ca_admitomatic.make_cert('admitomatic-webhook', ou='Admitomatic Webhook', hosts=['admitomatic.admitomatic.svc'])
-
-    toplevel = subprocess.check_output([
-        "nix-build",
-        local_root,
-        "-A", "ops.machines.\"" + fqdn + "\".config.passthru.hscloud.provision",
-    ]).decode().strip()
-    subprocess.check_call([toplevel])
-
-
-def usage():
-    sys.stderr.write("Usage: clustercfg <nodestrap|admincreds>\n")
-
-
-def main():
-    if len(sys.argv) < 2:
-        usage()
-        return 1
-
-    mode = sys.argv[1]
-    if mode == "nodestrap":
-        return nodestrap(sys.argv[2:])
-    elif mode == "nodestrap-nocerts":
-        return nodestrap(sys.argv[2:], nocerts=True)
-    elif mode == "admincreds":
-        return admincreds(sys.argv[2:])
-    elif mode == "smoketest":
-        sys.stdout.write("Smoke test passed.")
-        return 0
-    else:
-        usage()
-        return 1
-
-if __name__ == '__main__':
-    sys.exit(main() or 0)
diff --git a/cluster/clustercfg/cmd_admincreds.go b/cluster/clustercfg/cmd_admincreds.go
new file mode 100644
index 0000000..110c54d
--- /dev/null
+++ b/cluster/clustercfg/cmd_admincreds.go
@@ -0,0 +1,109 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"os/user"
+	"path/filepath"
+
+	"github.com/spf13/cobra"
+	"k8s.io/client-go/tools/clientcmd"
+	clientapi "k8s.io/client-go/tools/clientcmd/api"
+
+	"code.hackerspace.pl/hscloud/cluster/clustercfg/certs"
+	"code.hackerspace.pl/hscloud/go/workspace"
+)
+
+var admincredsCmd = &cobra.Command{
+	Use:   "admincreds",
+	Short: "Acquire emergency Kubernetes credentials",
+	Long: `
+Use secretstore secrets to generate a Kubernetes system:masters keypair and
+certificate. Only for use in emergencies.
+
+Your local username and hostname will make part of the cert and can be used
+for auditing of accesses to apiservers.
+`,
+	Run: func(cmd *cobra.Command, args []string) {
+		ws, err := workspace.Get()
+		if err != nil {
+			log.Fatalf("Could not figure out workspace: %v", err)
+		}
+
+		uname := "UNKNOWN"
+		if u, err := user.Current(); err == nil {
+			uname = u.Username
+		}
+		hostname := "UNKNOWN"
+		if h, err := os.Hostname(); err == nil {
+			hostname = h
+		}
+		breadcrumb := fmt.Sprintf("%s@%s", uname, hostname)
+
+		root := filepath.Join(ws, "cluster")
+		path := filepath.Join(ws, ".kubectl", "admincreds")
+		c := certs.Prepare(root, nil)
+		creds := c.MakeKubeEmergencyCreds(path, breadcrumb)
+		_ = creds
+
+		log.Printf("")
+		log.Printf("WARNING WARNING WARNING WARNING WARNING WARNING")
+		log.Printf("===============================================")
+		log.Printf("")
+		log.Printf("You are requesting ADMIN credentials.")
+		log.Printf("")
+		log.Printf("You likely shouldn't be doing this, and")
+		log.Printf("instead should be using `prodaccess`.")
+		log.Printf("")
+		log.Printf("===============================================")
+		log.Printf("WARNING WARNING WARNING WARNING WARNING WARNING")
+		log.Printf("")
+
+		log.Printf("Issuing certs...")
+		if err := creds.Ensure(); err != nil {
+			log.Fatalf("Failed: %v", err)
+		}
+
+		log.Printf("Configuring kubectl...")
+		caPath, certPath, keyPath := creds.Paths()
+		if err := installKubeletConfig(caPath, certPath, keyPath, "emergency.k0"); err != nil {
+			log.Fatalf("Failed: %v", err)
+		}
+
+		log.Fatalf("Done. Use kubectl --context=emergency.k0")
+	},
+}
+
+func installKubeletConfig(caPath, certPath, keyPath, configName string) error {
+	ca := clientcmd.NewDefaultPathOptions()
+	config, err := ca.GetStartingConfig()
+	if err != nil {
+		return fmt.Errorf("getting initial config failed: %w", err)
+	}
+
+	config.AuthInfos[configName] = &clientapi.AuthInfo{
+		ClientCertificate: certPath,
+		ClientKey:         keyPath,
+	}
+
+	config.Clusters[configName] = &clientapi.Cluster{
+		CertificateAuthority: caPath,
+		Server:               "https://k0.hswaw.net:4001",
+	}
+
+	config.Contexts[configName] = &clientapi.Context{
+		AuthInfo:  configName,
+		Cluster:   configName,
+		Namespace: "default",
+	}
+
+	if err := clientcmd.ModifyConfig(ca, *config, true); err != nil {
+		return fmt.Errorf("modifying config failed: %w", err)
+	}
+	return nil
+}
+
+func init() {
+	rootCmd.AddCommand(admincredsCmd)
+}
diff --git a/cluster/clustercfg/cmd_gencerts.go b/cluster/clustercfg/cmd_gencerts.go
new file mode 100644
index 0000000..6cb6431
--- /dev/null
+++ b/cluster/clustercfg/cmd_gencerts.go
@@ -0,0 +1,63 @@
+package main
+
+import (
+	"log"
+	"path/filepath"
+	"strings"
+
+	"github.com/spf13/cobra"
+
+	"code.hackerspace.pl/hscloud/cluster/clustercfg/certs"
+	"code.hackerspace.pl/hscloud/go/workspace"
+)
+
+var flagFQDNs []string
+
+var gencertsCmd = &cobra.Command{
+	Use:   "gencerts",
+	Short: "(re)generate keys/certs for k0 cluster",
+	Long: `
+If you're adding a new cluster node, run this. It will populate //cluster/secrets
+and //cluster/certificates with new certs/keys.
+
+By default, the nodes to generate certificates for are automatically discovered
+by querying the local Nix machines defined in //ops, looking for anything that
+has hscloud.kube.controller.enabled. That can be slow and/or incorrect. To override
+node names, set --fqdn (either comma-separate them or repeat flags).
+`,
+	Run: func(cmd *cobra.Command, args []string) {
+		ws, err := workspace.Get()
+		if err != nil {
+			log.Fatalf("Could not figure out workspace: %v", err)
+		}
+		path := filepath.Join(ws, "cluster")
+
+		fqdns := flagFQDNs
+		if len(fqdns) == 0 {
+			log.Printf("--fqdn not set, figuring out machines from Nix...")
+			err = workspace.EvalHscloudNix(cmd.Context(), &fqdns, "ops.exports.kubeMachineNames")
+			if err != nil {
+				log.Fatalf("Could not figure out Kubernetes machine FQDNs: %v", err)
+			}
+		}
+
+		for _, fqdn := range fqdns {
+			parts := strings.Split(fqdn, ".")
+			if len(parts) != 3 || parts[1] != "hswaw" || parts[2] != "net" {
+				log.Fatalf("Invalid FQDN %q: must be xxx.hswaw.net.", fqdn)
+			}
+		}
+
+		log.Printf("Machines: --fqdn %s", strings.Join(fqdns, ","))
+		c := certs.Prepare(path, fqdns)
+		if err := c.Ensure(); err != nil {
+			log.Fatalf("Failed: %v", err)
+		}
+		log.Printf("Done.")
+	},
+}
+
+func init() {
+	gencertsCmd.Flags().StringSliceVar(&flagFQDNs, "fqdn", nil, "List of machine FQDNs to generate certs for. If not set, will be automatically figured out from Nix modules in local checkout (slow).")
+	rootCmd.AddCommand(gencertsCmd)
+}
diff --git a/cluster/clustercfg/main.go b/cluster/clustercfg/main.go
new file mode 100644
index 0000000..823932d
--- /dev/null
+++ b/cluster/clustercfg/main.go
@@ -0,0 +1,20 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+var rootCmd = &cobra.Command{
+	Use:   "clustercfg",
+	Short: "admin management tool for k0 cluster",
+}
+
+func main() {
+	if err := rootCmd.Execute(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
diff --git a/cluster/doc/admin.md b/cluster/doc/admin.md
index 097e749..2f9ba18 100644
--- a/cluster/doc/admin.md
+++ b/cluster/doc/admin.md
@@ -29,8 +29,9 @@
 
  - bring up a new node with nixos, the configuration doesn't matter and will be
    nuked anyway
- - edit cluster/nix/defs-machines.nix
- - `bazel run //cluster/clustercfg nodestrap bc01nXX.hswaw.net`
+ - add machine to cluster/machines and ops/machines.nix
+ - generate certs with `bazel run //cluster/clustercfg gencerts`
+ - deploy using ops (see ops/README.md)
 
 Applying kubecfg state
 ----------------------
diff --git a/ops/exports.nix b/ops/exports.nix
new file mode 100644
index 0000000..3356607
--- /dev/null
+++ b/ops/exports.nix
@@ -0,0 +1,14 @@
+{ hscloud, pkgs, hscloudForPkgs, ... }:
+
+{
+  # Used by clustercfg to figure out which machines need kube certs.
+  kubeMachineNames = let
+    isKubeMachine = n: value:
+      n != "__readTree" &&
+      (builtins.hasAttr "hscloud" value.options) &&
+      (builtins.hasAttr "kube" value.options.hscloud) &&
+      value.options.hscloud.kube.control.enable.value;
+    machines = pkgs.lib.filterAttrs isKubeMachine hscloud.ops.machines;
+    names = pkgs.lib.mapAttrsToList (name: _: name) machines;
+  in names;
+}
diff --git a/ops/monitoring/lib/cluster.libsonnet b/ops/monitoring/lib/cluster.libsonnet
index 00aa792..c742df0 100644
--- a/ops/monitoring/lib/cluster.libsonnet
+++ b/ops/monitoring/lib/cluster.libsonnet
@@ -75,7 +75,7 @@
                 //
                 // When contacting the API server, we hardcode the 'hswaw.net' DNS suffix as
                 // our API server's TLS certificate only has a CN/SAN for its full FQDN, not
-                // the .svc.cluster.local shorthand (see //cluster/clustercfg:clustercfg.py).
+                // the .svc.cluster.local shorthand (see //cluster/clustercfg).
                 local kubeScrapeNodeMetrics = function(name, path) kubeScrapeConfig(name, "node") {
                     relabel_configs: [
                         {