certificate overhaul

.gitignore

@@ -1 +1,2 @@
-.vscode
+.vscode
+k8s/ingress.yaml

cmd/webhook/httpServer.go

@@ -11,7 +11,6 @@ import (
 	"encoding/json"
 	"net/http"
 
-	"mutating-webhook/internal/certificate"
 	"mutating-webhook/internal/config"
 	"mutating-webhook/internal/operations"
 
@@ -37,16 +36,9 @@ func strictTransport(w http.ResponseWriter) {
 	w.Header().Add("Strict-Transport-Security", "max-age=63072000")
 }
 
-func httpServer() {
-	var serverCertificate tls.Certificate
-	if config.DefaultConfig().WebServerCertificate == "" || cfg.WebServerKey == "" {
-		log.Printf("[INFO] No webserver certificate configured, automatically generating self signed certificate.")
-		serverCertificate = certificate.CreateServerCert()
-	} else {
-		log.Fatal("[FATAL] Code to support external webserver certificate is not complete yet. ./cmd/webhook/httpServer.go:36")
-		// read certificate from files
-		// check for errors
-	}
+func httpServer(cfg *config.Config) {
+	serverCertificate, _ := tls.X509KeyPair(append([]byte(cfg.CertCert), []byte(cfg.CACert)...), []byte(cfg.CertPrivateKey))
+
 	path := http.NewServeMux()
 
 	connection := &http.Server{
@@ -73,7 +65,7 @@ func httpServer() {
 
 	ah := &admissionHandler{
 		decoder: serializer.NewCodecFactory(runtime.NewScheme()).UniversalDeserializer(),
-		config:  &cfg,
+		config:  cfg,
 	}
 
 	// pod admission

cmd/webhook/main.go

@@ -29,7 +29,7 @@ func main() {
 	// initialize application configuration
 	cfg = config.Init()
 
-	go httpServer()
+	go httpServer(&cfg)
 
 	forever()
 }

config.yaml

@@ -1,6 +1,6 @@
 ---
 allow-admin-nomutate: false
-allow-admin-nomutate-toggle: 2d77b689-dc14-40a5-8971-34c62999335c
+allow-admin-nomutate-toggle: 7b068a99-c02b-410a-bd59-3514bac85e7a
 dockerhub-registry: registry.hub.docker.com
 mutate-ignored-images:
 - goharbor/chartmuseum-photon
@@ -12,4 +12,4 @@ mutate-ignored-images:
 - goharbor/harbor-portal
 - goharbor/redis-photon
 - goharbor/registry-photon
-- goharbor/trivy-adapter-photon
+- goharbor/trivy-adapter-photon

internal/certificate/create-ca.go

@@ -2,18 +2,19 @@ package certificate
 
 import (
 	"bytes"
+	"fmt"
+	"log"
 	"strconv"
 	"time"
 
 	"crypto/rand"
-	"crypto/rsa"
 	"crypto/x509"
 	"crypto/x509/pkix"
 	"encoding/pem"
 	"math/big"
 )
 
-func CreateCA() ([]byte, []byte, []byte, error) {
+func CreateCA(privateKey string) (string, error) {
 	serial, _ := strconv.ParseInt(time.Now().Format("20060102150405"), 10, 64)
 	ca := &x509.Certificate{
 		SerialNumber: big.NewInt(serial),
@@ -37,14 +38,18 @@ func CreateCA() ([]byte, []byte, []byte, error) {
 		SignatureAlgorithm:    x509.SHA384WithRSA,
 	}
 
-	keyPair, err := rsa.GenerateKey(rand.Reader, 4096)
+	pemKey, _ := pem.Decode([]byte(privateKey))
+	if pemKey == nil || pemKey.Type != "RSA PRIVATE KEY" {
+		return "", fmt.Errorf("failed to decode PEM block containing private key")
+	}
+	keyPair, err := x509.ParsePKCS1PrivateKey(pemKey.Bytes)
 	if err != nil {
-		return []byte(""), []byte(""), []byte(""), err
+		return "", err
 	}
 
 	certBytes, err := x509.CreateCertificate(rand.Reader, ca, ca, &keyPair.PublicKey, keyPair)
 	if err != nil {
-		return []byte(""), []byte(""), []byte(""), err
+		return "", err
 	}
 
 	c := new(bytes.Buffer)
@@ -53,17 +58,6 @@ func CreateCA() ([]byte, []byte, []byte, error) {
 		Bytes: certBytes,
 	})
 
-	k := new(bytes.Buffer)
-	pem.Encode(k, &pem.Block{
-		Type:  "RSA PRIVATE KEY",
-		Bytes: x509.MarshalPKCS1PrivateKey(keyPair),
-	})
-
-	p := new(bytes.Buffer)
-	pem.Encode(p, &pem.Block{
-		Type:  "PUBLIC KEY",
-		Bytes: x509.MarshalPKCS1PublicKey(&keyPair.PublicKey),
-	})
-
-	return c.Bytes(), k.Bytes(), p.Bytes(), nil
+	log.Printf("[DEBUG] Generated Certificate Authority Certificate:\n%s", c)
+	return c.String(), nil
 }

internal/certificate/create-cert.go

@@ -1,72 +0,0 @@
-package certificate
-
-import (
-	"bytes"
-	"strconv"
-	"time"
-
-	"crypto/rand"
-	"crypto/rsa"
-	"crypto/x509"
-	"crypto/x509/pkix"
-	"encoding/pem"
-	"math/big"
-)
-
-func CreateCert() ([]byte, []byte, []byte, error) {
-	serial, _ := strconv.ParseInt(time.Now().Format("20060102150405"), 10, 64)
-	ca := &x509.Certificate{
-		SerialNumber: big.NewInt(serial + 1),
-		Subject: pkix.Name{
-			Organization: []string{"Kubernetes Mutating Webserver"},
-			Country:      []string{"K8S"},
-			Province:     []string{"Cluster Service"},
-			Locality:     []string{"Cluster Local"},
-			//StreetAddress: []string{""},
-			//PostalCode:    []string{""},
-		},
-		NotBefore: time.Now(),
-		NotAfter:  time.Now().AddDate(1, 6, 0),
-		ExtKeyUsage: []x509.ExtKeyUsage{
-			x509.ExtKeyUsageClientAuth,
-			x509.ExtKeyUsageServerAuth,
-		},
-		DNSNames: []string{
-			"svc.cluster.local",
-			"*.svc.cluster.local",
-		},
-		SubjectKeyId:       []byte{1, 2, 3, 4, 6},
-		KeyUsage:           x509.KeyUsageDigitalSignature,
-		SignatureAlgorithm: x509.SHA384WithRSA,
-	}
-
-	keyPair, err := rsa.GenerateKey(rand.Reader, 4096)
-	if err != nil {
-		return []byte(""), []byte(""), []byte(""), err
-	}
-
-	certBytes, err := x509.CreateCertificate(rand.Reader, ca, ca, &keyPair.PublicKey, keyPair)
-	if err != nil {
-		return []byte(""), []byte(""), []byte(""), err
-	}
-
-	c := new(bytes.Buffer)
-	pem.Encode(c, &pem.Block{
-		Type:  "CERTIFICATE",
-		Bytes: certBytes,
-	})
-
-	k := new(bytes.Buffer)
-	pem.Encode(k, &pem.Block{
-		Type:  "RSA PRIVATE KEY",
-		Bytes: x509.MarshalPKCS1PrivateKey(keyPair),
-	})
-
-	p := new(bytes.Buffer)
-	pem.Encode(p, &pem.Block{
-		Type:  "PUBLIC KEY",
-		Bytes: x509.MarshalPKCS1PublicKey(&keyPair.PublicKey),
-	})
-
-	return c.Bytes(), k.Bytes(), p.Bytes(), nil
-}

internal/certificate/create-csr.go

@@ -0,0 +1,53 @@
+package certificate
+
+import (
+	"bytes"
+	"fmt"
+	"log"
+
+	"crypto/rand"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/pem"
+)
+
+func CreateCSR(privateKey string) (string, error) {
+	csr := x509.CertificateRequest{
+		Subject: pkix.Name{
+			Organization: []string{"Kubernetes Mutating Webserver"},
+			Country:      []string{"K8S"},
+			Province:     []string{"Cluster Service"},
+			Locality:     []string{"Cluster Local"},
+			//StreetAddress: []string{""},
+			//PostalCode:    []string{""},
+		},
+		DNSNames: []string{
+			"svc.cluster.local",
+			"*.svc.cluster.local",
+		},
+		SignatureAlgorithm: x509.SHA384WithRSA,
+	}
+
+	pemKey, _ := pem.Decode([]byte(privateKey))
+	if pemKey == nil || pemKey.Type != "RSA PRIVATE KEY" {
+		return "", fmt.Errorf("failed to decode PEM block containing private key")
+	}
+	keyPair, err := x509.ParsePKCS1PrivateKey(pemKey.Bytes)
+	if err != nil {
+		return "", err
+	}
+
+	csrData, err := x509.CreateCertificateRequest(rand.Reader, &csr, keyPair)
+	if err != nil {
+		return "", err
+	}
+
+	c := new(bytes.Buffer)
+	pem.Encode(c, &pem.Block{
+		Type:  "CERTIFICATE REQUEST",
+		Bytes: csrData,
+	})
+
+	log.Printf("[TRACE] Generated Host CSR:\n%s", c.String())
+	return c.String(), nil
+}

internal/certificate/create-key.go

@@ -0,0 +1,15 @@
+package certificate
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+)
+
+func CreateRSAKeyPair(bytes int) (*rsa.PrivateKey, error) {
+	keyPair, err := rsa.GenerateKey(rand.Reader, bytes)
+	if err != nil {
+		return &rsa.PrivateKey{}, err
+	}
+
+	return keyPair, nil
+}

internal/certificate/create-server-cert.go

@@ -1,43 +0,0 @@
-package certificate
-
-import (
-	"bytes"
-	"log"
-
-	"crypto/rand"
-	"crypto/tls"
-	"crypto/x509"
-	"encoding/pem"
-)
-
-func CreateServerCert() tls.Certificate {
-	caCertPem, caPrivKeyPem, _, _ := CreateCA()
-	certCertPem, certPrivKeyPem, certPublicKeyPem, _ := CreateCert()
-
-	caCertBlob, _ := pem.Decode(caCertPem)
-	caCert, _ := x509.ParseCertificate(caCertBlob.Bytes)
-	caPrivKeyBlob, _ := pem.Decode(caPrivKeyPem)
-	caPrivKey, _ := x509.ParsePKCS1PrivateKey(caPrivKeyBlob.Bytes)
-	certCertBlob, _ := pem.Decode(certCertPem)
-	certCert, _ := x509.ParseCertificate(certCertBlob.Bytes)
-	certPublicKeyBlob, _ := pem.Decode(certPublicKeyPem)
-	certPublicKey, _ := x509.ParsePKCS1PublicKey(certPublicKeyBlob.Bytes)
-
-	signedCert, err := x509.CreateCertificate(rand.Reader, certCert, caCert, certPublicKey, caPrivKey)
-	if err != nil {
-		log.Fatalf("[FATAL] CreateCertificate: %v", err)
-	}
-
-	serverCertPem := new(bytes.Buffer)
-	pem.Encode(serverCertPem, &pem.Block{
-		Type:  "CERTIFICATE",
-		Bytes: signedCert,
-	})
-
-	serverCert, err := tls.X509KeyPair(append(serverCertPem.Bytes(), caCertPem...), certPrivKeyPem)
-	if err != nil {
-		log.Fatalf("[FATAL] x509KeyPair: %v", err)
-	}
-
-	return serverCert
-}

internal/certificate/sign-cert.go

@@ -0,0 +1,74 @@
+package certificate
+
+import (
+	"bytes"
+	"fmt"
+	"strconv"
+	"time"
+
+	"crypto/rand"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/pem"
+	"math/big"
+)
+
+func SignCert(caCertPem, caPrivKeyPem, csrPem string) (string, error) {
+	caCertData, _ := pem.Decode([]byte(caCertPem))
+	caCert, err := x509.ParseCertificate(caCertData.Bytes)
+	if err != nil {
+		return "", fmt.Errorf("parse cert %v", err)
+	}
+
+	pemKey, _ := pem.Decode([]byte(caPrivKeyPem))
+	if pemKey == nil || pemKey.Type != "RSA PRIVATE KEY" {
+		return "", fmt.Errorf("failed to decode PEM block containing private key")
+	}
+	keyPair, err := x509.ParsePKCS1PrivateKey(pemKey.Bytes)
+	if err != nil {
+		return "", fmt.Errorf("private key %v", err)
+	}
+
+	csrData, _ := pem.Decode([]byte(csrPem))
+	csr, err := x509.ParseCertificateRequest(csrData.Bytes)
+	if err != nil {
+		return "", fmt.Errorf("parse csr %v", err)
+	}
+
+	serial, _ := strconv.ParseInt(time.Now().Format("20060102150405"), 10, 64)
+	certTemplate := x509.Certificate{
+		SerialNumber: big.NewInt(serial + 1),
+		Issuer:       caCert.Issuer,
+		Subject: pkix.Name{
+			Organization:  []string{"Kubernetes Mutating Webserver"},
+			Country:       csr.Subject.Country,
+			Province:      []string{"Cluster Service"},
+			Locality:      []string{"Cluster Local"},
+			StreetAddress: csr.Subject.StreetAddress,
+			PostalCode:    csr.Subject.PostalCode,
+		},
+		NotBefore: time.Now(),
+		NotAfter:  time.Now().AddDate(1, 6, 0),
+		KeyUsage:  x509.KeyUsageDigitalSignature,
+		ExtKeyUsage: []x509.ExtKeyUsage{
+			x509.ExtKeyUsageClientAuth,
+			x509.ExtKeyUsageServerAuth,
+		},
+		DNSNames:           csr.DNSNames,
+		Signature:          csr.Signature,
+		SignatureAlgorithm: csr.SignatureAlgorithm,
+		PublicKey:          csr.PublicKey,
+		PublicKeyAlgorithm: csr.PublicKeyAlgorithm,
+	}
+
+	certBytes, err := x509.CreateCertificate(rand.Reader, &certTemplate, caCert, csr.PublicKey, keyPair)
+	if err != nil {
+		return "", fmt.Errorf("sign %v", err)
+	}
+	c := new(bytes.Buffer)
+	pem.Encode(c, &pem.Block{
+		Type:  "CERTIFICATE",
+		Bytes: certBytes,
+	})
+	return c.String(), nil
+}

internal/config/config.go

@@ -35,9 +35,15 @@ type Config struct {
 
 	// mutation configuration
 	AllowAdminNoMutate       bool     `env:"allow_admin_nomutate" default:"false"`
-	AllowAdminNoMutateToggle string   `env:"allow_admin_nomutate_toggle" default:"2d77b689-dc14-40a5-8971-34c62999335c"`
+	AllowAdminNoMutateToggle string   `env:"allow_admin_nomutate_toggle" default:"7b068a99-c02b-410a-bd59-3514bac85e7a"`
 	DockerhubRegistry        string   `env:"dockerhub_registry" default:"registry.hub.docker.com"`
 	MutateIgnoredImages      []string `ignored:"true"`
+
+	// certificate configuration
+	CACert         string `env:"ca_cert"`
+	CAPrivateKey   string `env:"ca_private_key"`
+	CertCert       string `env:"cert_cert"`
+	CertPrivateKey string `env:"cert_private_key"`
 }
 
 // DefaultConfig initializes the config variable for use with a prepared set of defaults.

internal/config/configFile.go

@@ -9,10 +9,18 @@ import (
 )
 
 type configFileStruct struct {
-	AllowAdminNoMutate       bool     `yaml:"allow-admin-nomutate"`
-	AllowAdminNoMutateToggle string   `yaml:"allow-admin-nomutate-toggle"`
-	DockerhubRegistry        string   `yaml:"dockerhub-registry"`
-	MutateIgnoredImages      []string `yaml:"mutate-ignored-images"`
+	AllowAdminNoMutate       bool       `yaml:"allow-admin-nomutate"`
+	AllowAdminNoMutateToggle string     `yaml:"allow-admin-nomutate-toggle"`
+	DockerhubRegistry        string     `yaml:"dockerhub-registry"`
+	MutateIgnoredImages      []string   `yaml:"mutate-ignored-images"`
+	CertificateAuthority     CertStruct `yaml:"certificate-authority"`
+	Certificate              CertStruct `yaml:"certificate"`
+}
+
+type CertStruct struct {
+	Certificate string `yaml:"certificate"`
+	PrivateKey  string `yaml:"private-key"`
+	PublicKey   string `yaml:"public-key"`
 }
 
 func getConfigFileData(fileLocation string) (configFileStruct, error) {

internal/config/initialize.go

@@ -1,8 +1,13 @@
 package config
 
 import (
+	"bytes"
+	"crypto/x509"
+	"encoding/pem"
 	"flag"
+	"fmt"
 	"log"
+	"mutating-webhook/internal/certificate"
 	"os"
 	"reflect"
 	"strings"
@@ -70,25 +75,108 @@ func Init() Config {
 	}
 	time.Now().Format(cfg.TimeFormat)
 
-	// print running config
-	printRunningConfig(&cfg, cfgInfo)
-
 	// read config file
 	configFileData, err := getConfigFileData(cfg.ConfigFile)
 	if err != nil {
 		log.Fatalf("[FATAL] Unable to read configuration file")
 	}
-	if cfg.AllowAdminNoMutate == false {
-		cfg.AllowAdminNoMutate = configFileData.AllowAdminNoMutate
+	updateValues(&cfg, configFileData)
+
+	// Generate certificates if needed
+	if err := certificateInit(&cfg); err != nil {
+		log.Fatalf("[FATAL] Unable to initialize certificate data: %v", err)
 	}
-	if cfg.AllowAdminNoMutateToggle == "2d77b689-dc14-40a5-8971-34c62999335c" {
-		cfg.AllowAdminNoMutateToggle = configFileData.AllowAdminNoMutateToggle
-	}
-	if cfg.DockerhubRegistry == "registry.hub.docker.com" {
-		cfg.DockerhubRegistry = configFileData.DockerhubRegistry
-	}
-	cfg.MutateIgnoredImages = configFileData.MutateIgnoredImages
+
+	// print running config
+	printRunningConfig(&cfg, cfgInfo)
 
 	log.Println("[INFO] initialization sequence complete")
 	return cfg
 }
+
+func updateValues(cfg *Config, configFileData configFileStruct) {
+	if cfg.AllowAdminNoMutate == false && configFileData.AllowAdminNoMutate != false {
+		cfg.AllowAdminNoMutate = configFileData.AllowAdminNoMutate
+	}
+	if cfg.AllowAdminNoMutateToggle == "7b068a99-c02b-410a-bd59-3514bac85e7a" && configFileData.AllowAdminNoMutateToggle != "2d77b689-dc14-40a5-8971-34c62999335c" {
+		cfg.AllowAdminNoMutateToggle = configFileData.AllowAdminNoMutateToggle
+	}
+	if cfg.DockerhubRegistry == "registry.hub.docker.com" && configFileData.DockerhubRegistry != "registry.hub.docker.com" {
+		cfg.DockerhubRegistry = configFileData.DockerhubRegistry
+	}
+	if len(configFileData.MutateIgnoredImages) != 0 {
+		cfg.MutateIgnoredImages = configFileData.MutateIgnoredImages
+	}
+	if len(configFileData.CertificateAuthority.Certificate) != 0 {
+		cfg.CACert = configFileData.CertificateAuthority.Certificate
+	}
+	if len(configFileData.CertificateAuthority.PrivateKey) != 0 {
+		cfg.CAPrivateKey = configFileData.CertificateAuthority.PrivateKey
+	}
+	if len(configFileData.Certificate.Certificate) != 0 {
+		cfg.CertCert = configFileData.Certificate.Certificate
+	}
+	if len(configFileData.Certificate.PrivateKey) != 0 {
+		cfg.CertPrivateKey = configFileData.Certificate.PrivateKey
+	}
+}
+
+func certificateInit(cfg *Config) error {
+	// certificate authority private key does not exist, generate key pair
+	if len(cfg.CAPrivateKey) == 0 {
+		log.Printf("[TRACE] No certificate authority private key detected")
+		keyPair, err := certificate.CreateRSAKeyPair(4096)
+		if err != nil {
+			return fmt.Errorf("Create RSA Key (%v)", err)
+		}
+		// pem encode private key
+		k := new(bytes.Buffer)
+		pem.Encode(k, &pem.Block{
+			Type:  "RSA PRIVATE KEY",
+			Bytes: x509.MarshalPKCS1PrivateKey(keyPair),
+		})
+		cfg.CAPrivateKey = k.String()
+	}
+
+	// certificate authority certificate is missing, create it
+	if len(cfg.CACert) == 0 {
+		log.Printf("[TRACE] No certificate authority certificate detected")
+		caCert, err := certificate.CreateCA(cfg.CAPrivateKey)
+		if err != nil {
+			return fmt.Errorf("Create CA (%v)", err)
+		}
+		cfg.CACert = caCert
+	}
+
+	// certificate private key does not exist, generate key pair
+	if len(cfg.CertPrivateKey) == 0 {
+		log.Printf("[TRACE] No server private key detected")
+		keyPair, err := certificate.CreateRSAKeyPair(4096)
+		if err != nil {
+			return fmt.Errorf("Create RSA Key (%v)", err)
+		}
+		// pem encode private key
+		k := new(bytes.Buffer)
+		pem.Encode(k, &pem.Block{
+			Type:  "RSA PRIVATE KEY",
+			Bytes: x509.MarshalPKCS1PrivateKey(keyPair),
+		})
+		cfg.CertPrivateKey = k.String()
+	}
+
+	// certificate certificate is missing, create it
+	if len(cfg.CertCert) == 0 {
+		log.Printf("[TRACE] No server certificate detected")
+		csr, err := certificate.CreateCSR(cfg.CertPrivateKey)
+		if err != nil {
+			return fmt.Errorf("Create CSR (%v)", err)
+		}
+		cert, err := certificate.SignCert(cfg.CACert, cfg.CAPrivateKey, csr)
+		if err != nil {
+			return fmt.Errorf("Sign Cert (%v)", err)
+		}
+		cfg.CertCert = cert
+	}
+
+	return nil
+}

k8s/admission.yaml

@@ -0,0 +1,19 @@
+---
+apiVersion: admissionregistration.k8s.io/v1beta1
+kind: ValidatingWebhookConfiguration
+metadata:
+  name: deployment-validation
+webhooks:
+  - name: deployment-validation.default.svc
+    clientConfig:
+      service:
+        name: admission-server
+        namespace: default
+        path: "/validate/deployments"
+      caBundle: "${CA_BUNDLE}"
+    rules:
+      - operations: ["CREATE","DELETE"]
+        apiGroups: ["apps"]
+        apiVersions: ["v1"]
+        resources: ["deployments"]
+    failurePolicy: Ignore

k8s/configmap.yaml

@@ -0,0 +1,18 @@
+---
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: webhook-config
+data:
+  config.yaml: |-
+    mutate-ignored-images:
+    - goharbor/chartmuseum-photon
+    - goharbor/harbor-core
+    - goharbor/harbor-db
+    - goharbor/harbor-jobservice
+    - goharbor/notary-server-photon
+    - goharbor/notary-signer-photon
+    - goharbor/harbor-portal
+    - goharbor/redis-photon
+    - goharbor/registry-photon
+    - goharbor/trivy-adapter-photon

k8s/daemonset.yaml

@@ -0,0 +1,55 @@
+---
+apiVersion: apps/v1
+kind: DaemonSet
+metadata:
+  name: mutating-webhool
+  labels:
+    app: mutating-webhook
+spec:
+  selector:
+    matchLabels:
+      app: mutating-webhook
+  template:
+    metadata:
+      labels:
+        app: mutating-webhook
+    spec:
+      volumes:
+      - name: config
+        configMap:
+          name: webhook-config
+          defaultMode: 493
+          optional: false
+      containers:
+      - name: mutating-webhook
+        imagePullPolicy: Always
+        env:
+        - name: DOCKERHUB_REGISTRY
+          value: registry.c.test-chamber-13.lan/dockerhub
+        - name: ALLOW_ADMIN_NOMUTATE
+          value: "true"
+        - name: CONFIG_FILE
+          value: /tmp/config/config.yaml
+        image: registry.c.test-chamber-13.lan/library/webhook:latest
+        volumeMounts:
+        - name: config
+          mountPath: /tmp/config
+        livenessProbe:
+          httpGet:
+            path: /healthcheck
+            port: 8443
+            scheme: HTTPS
+          periodSeconds: 15
+          initialDelaySeconds: 10
+          timeoutSeconds: 2
+          failureThreshold: 1
+        readinessProbe:
+          httpGet:
+            path: /healthcheck
+            port: 8443
+            scheme: HTTPS
+          initialDelaySeconds: 10
+          timeoutSeconds: 2
+          failureThreshold: 1
+      terminationGracePeriodSeconds: 30
+

k8s/service.yaml

@@ -0,0 +1,14 @@
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: webhook
+spec:
+  ports:
+    - name: https
+      protocol: TCP
+      port: 443
+      targetPort: 8443
+  selector:
+    app: mutating-webhook
+  type: ClusterIP

k8s/webhook.yaml

@@ -0,0 +1,18 @@
+---
+apiVersion: admissionregistration.k8s.io/v1beta1
+kind: MutatingWebhookConfiguration
+metadata:
+  name: pod-mutation
+webhooks:
+  - name: pod-mutation.default.svc
+    clientConfig:
+      service:
+        name: webhook
+        namespace: default
+        path: "/api/v1/mutate/pod"
+    rules:
+      - operations: ["CREATE", ]
+        apiGroups: [""]
+        apiVersions: ["v1"]
+        resources: ["pods"]
+    failurePolicy: Ignore