Add a MutatingAdmissionWebook + Defaulting/Validation for MachineDeployment

.circleci/config.yml

@@ -48,10 +48,12 @@ jobs:
           key: repo-{{ .Environment.CIRCLE_SHA1 }}
       - run: DEP_RELEASE_TAG=v0.5.0 curl https://raw.githubusercontent.com/golang/dep/master/install.sh | sh
       - run: make machine-controller
+      - run: make webhook
       - save_cache:
           key: machine-controller-{{ .Revision }}
           paths:
             - /go/src/github.com/kubermatic/machine-controller
+            - /go/src/github.com/kubermatic/webhook
   end-to-end:
     <<: *defaults
     steps:

.gitignore

@@ -8,3 +8,8 @@ test/tools/verify/verify
 terraform
 terraform-provider-hcloud
 .kubeconfig
+examples/*.pem
+examples/*.csr
+examples/*.srl
+webhook
+!cmd/webhook

Dockerfile

@@ -3,5 +3,6 @@ FROM alpine:3.7
 RUN apk add --no-cache ca-certificates cdrkit
 
 COPY machine-controller /usr/local/bin
+COPY webhook /usr/local/bin
 
 USER nobody

Makefile

@@ -30,7 +30,13 @@ machine-controller: $(shell find cmd pkg -name '*.go') vendor
 		-o machine-controller \
 		github.com/kubermatic/machine-controller/cmd/controller
 
-docker-image: machine-controller docker-image-nodep
+webhook: $(shell find cmd pkg -name '*.go') vendor
+	go build -v \
+		-ldflags '-s -w' \
+		-o webhook \
+		github.com/kubermatic/machine-controller/cmd/webhook
+
+docker-image: machine-controller admission-webhook docker-image-nodep
 
 # This target exists because in our CI
 # we do not want to restore the vendor
@@ -68,3 +74,31 @@ e2e-cluster:
 e2e-destroy:
 	./test/tools/integration/cleanup_machines.sh
 	make -C test/tools/integration destroy
+
+examples/ca-key.pem:
+	openssl genrsa -out examples/ca-key.pem 4096
+
+examples/ca-cert.pem: examples/ca-key.pem
+	openssl req -x509 -new -nodes -key examples/ca-key.pem \
+    -subj "/C=US/ST=CA/O=Acme/CN=k8s-machine-controller-ca" \
+		-sha256 -days 10000 -out examples/ca-cert.pem
+
+examples/admission-key.pem: examples/ca-cert.pem
+	openssl genrsa -out examples/admission-key.pem 2048
+	chmod 0600 examples/admission-key.pem
+
+examples/admission-cert.pem: examples/admission-key.pem
+	openssl req -new -sha256 \
+    -key examples/admission-key.pem \
+    -subj "/C=US/ST=CA/O=Acme/CN=machine-controller-webhook.kube-system.svc" \
+    -out examples/admission.csr
+	openssl x509 -req -in examples/admission.csr -CA examples/ca-cert.pem \
+		-CAkey examples/ca-key.pem -CAcreateserial \
+		-out examples/admission-cert.pem -days 10000 -sha256
+
+deploy: examples/admission-cert.pem
+	@cat examples/machine-controller.yaml \
+		|sed "s/__admission_ca_cert__/$(shell cat examples/ca-cert.pem|base64 -w0)/g" \
+		|sed "s/__admission_cert__/$(shell cat examples/admission-cert.pem|base64 -w0)/g" \
+		|sed "s/__admission_key__/$(shell cat examples/admission-key.pem|base64 -w0)/g" \
+		|kubectl apply -f -

README.md

@@ -23,7 +23,7 @@
 
 ## Deploy the machine-controller
 
-`kubectl apply -f examples/machine-controller.yaml`
+`make deploy`
 
 ## Creating a machineDeployment
 ```bash

cmd/webhook/main.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"flag"
+
+	"github.com/golang/glog"
+
+	"github.com/kubermatic/machine-controller/pkg/admission"
+)
+
+var (
+	admissionListenAddress string
+	admissionTLSCertPath   string
+	admissionTLSKeyPath    string
+)
+
+func main() {
+	flag.StringVar(&admissionListenAddress, "listen-address", ":9876", "The address on which the MutatingWebhook will listen on")
+	flag.StringVar(&admissionTLSCertPath, "tls-cert-path", "/tmp/cert/cert.pem", "The path of the TLS cert for the MutatingWebhook")
+	flag.StringVar(&admissionTLSKeyPath, "tls-key-path", "/tmp/cert/key.pem", "The path of the TLS key for the MutatingWebhook")
+	flag.Parse()
+
+	s := admission.New(admissionListenAddress)
+	if err := s.ListenAndServeTLS(admissionTLSCertPath, admissionTLSKeyPath); err != nil {
+		glog.Fatalf("Failed to start server: %v", err)
+	}
+	defer func() {
+		if err := s.Close(); err != nil {
+			glog.Fatalf("Failed to shutdown server: %v", err)
+		}
+	}()
+	glog.Infof("Listening on %s", admissionListenAddress)
+	select {}
+}

examples/machine-controller.yaml

@@ -189,6 +189,75 @@ spec:
               port: 8085
             periodSeconds: 5
 ---
+apiVersion: apps/v1beta2
+kind: Deployment
+metadata:
+  name: machine-controller-webhook
+  namespace: kube-system
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: machine-controller-webhook
+  template:
+    metadata:
+      labels:
+        app: machine-controller-webhook
+    spec:
+      containers:
+        - image: kubermatic/machine-controller:latest
+          imagePullPolicy: IfNotPresent
+          name: webhook
+          command:
+            - /usr/local/bin/webhook
+            - -logtostderr
+            - -v=6
+            - -listen-address=0.0.0.0:9876
+          volumeMounts:
+            - name: machine-controller-admission-cert
+              mountPath: /tmp/cert
+          livenessProbe:
+            httpGet:
+              path: /healthz
+              port: 9876
+              scheme: HTTPS
+            initialDelaySeconds: 5
+            periodSeconds: 5
+          readinessProbe:
+            httpGet:
+              path: /healthz
+              port: 9876
+              scheme: HTTPS
+            periodSeconds: 5
+      volumes:
+        - name: machine-controller-admission-cert
+          secret:
+            secretName: machine-controller-admission-cert
+---
+apiVersion: v1
+kind: Secret
+metadata:
+  name: machine-controller-admission-cert
+  namespace: kube-system
+data:
+  "cert.pem": __admission_cert__
+  "key.pem": __admission_key__
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: machine-controller-webhook
+  namespace: kube-system
+spec:
+  ports:
+  - name: 443-9876
+    port: 443
+    protocol: TCP
+    targetPort: 9876
+  selector:
+    app: machine-controller-webhook
+  type: ClusterIP
+---
 apiVersion: v1
 kind: ServiceAccount
 metadata:
@@ -404,3 +473,27 @@ subjects:
   - kind: ServiceAccount
     name: machine-controller
     namespace: kube-system
+---
+apiVersion: admissionregistration.k8s.io/v1beta1
+kind: MutatingWebhookConfiguration
+metadata:
+  name: machinedeployments.machine-controller.kubermatic.io
+webhooks:
+- name: machinedeployments.machine-controller.kubermatic.io
+  failurePolicy: Fail
+  rules:
+  - apiGroups:
+    - "cluster.k8s.io"
+    apiVersions:
+    - v1alpha1
+    operations:
+    - CREATE
+    - UPDATE
+    resources:
+    - machinedeployments
+  clientConfig:
+    service:
+      namespace: kube-system
+      name: machine-controller-webhook
+      path: /machinedeployments
+    caBundle: __admission_ca_cert__

pkg/admission/admission.go

@@ -0,0 +1,49 @@
+package admission
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"reflect"
+	"time"
+
+	"github.com/golang/glog"
+	"github.com/mattbaird/jsonpatch"
+
+	"k8s.io/apimachinery/pkg/runtime"
+)
+
+func New(listenAddress string) *http.Server {
+	m := http.NewServeMux()
+	m.HandleFunc("/machinedeployments", handleFuncFactory(mutateMachineDeployments))
+	m.HandleFunc("/healthz", healthZHandler)
+	return &http.Server{
+		Addr:         listenAddress,
+		Handler:      m,
+		ReadTimeout:  5 * time.Second,
+		WriteTimeout: 10 * time.Second,
+	}
+}
+
+func healthZHandler(w http.ResponseWriter, r *http.Request) {
+	w.WriteHeader(http.StatusOK)
+}
+
+func newJSONPatch(original, current runtime.Object) ([]jsonpatch.JsonPatchOperation, error) {
+	originalGVK := original.GetObjectKind().GroupVersionKind()
+	currentGVK := current.GetObjectKind().GroupVersionKind()
+	if !reflect.DeepEqual(originalGVK, currentGVK) {
+		return nil, fmt.Errorf("GroupVersionKind %#v is expected to match %#v", originalGVK, currentGVK)
+	}
+	ori, err := json.Marshal(original)
+	if err != nil {
+		return nil, err
+	}
+	glog.V(4).Infof("jsonpatch: Marshaled original: %s", string(ori))
+	cur, err := json.Marshal(current)
+	if err != nil {
+		return nil, err
+	}
+	glog.V(4).Infof("jsonpatch: Marshaled target: %s", string(cur))
+	return jsonpatch.CreatePatch(ori, cur)
+}