[Draft] Validation Webhook for splunk-operator

api/v4/webhook.go

@@ -0,0 +1,60 @@
+/*
+Copyright (c) 2018-2022 Splunk Inc. All rights reserved.
+
+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 v4
+
+import (
+	"context"
+
+	ctrl "sigs.k8s.io/controller-runtime"
+	logf "sigs.k8s.io/controller-runtime/pkg/log"
+	"sigs.k8s.io/controller-runtime/pkg/webhook/admission"
+)
+
+var webhooklog = logf.Log.WithName("splunk-webhook")
+
+// SplunkValidator handles validation for all Splunk Enterprise CRDs
+// This is a dummy implementation to test webhook connectivity
+type SplunkValidator struct{}
+
+// SetupWebhookWithManager registers the centralized webhook with the manager
+func SetupWebhookWithManager(mgr ctrl.Manager) error {
+	validator := &SplunkValidator{}
+
+	mgr.GetWebhookServer().Register("/validate-splunk-enterprise", &admission.Webhook{
+		Handler: validator,
+	})
+
+	return nil
+}
+
+// Handle implements the admission.Handler interface
+// This is a dummy implementation that just logs and allows all requests
+func (v *SplunkValidator) Handle(ctx context.Context, req admission.Request) admission.Response {
+	// Dummy webhook - just log and allow everything
+	webhooklog.Info("WEBHOOK CALLED - Validation webhook is working!",
+		"kind", req.Kind.Kind,
+		"name", req.Name,
+		"namespace", req.Namespace,
+		"operation", req.Operation,
+		"user", req.UserInfo.Username)
+
+	// Always allow - this is just for testing webhook connectivity
+	return admission.Allowed("webhook is working - all requests allowed")
+}
+
+// Ensure SplunkValidator implements admission.Handler
+var _ admission.Handler = &SplunkValidator{}

cmd/main.go

@@ -221,6 +221,12 @@ func main() {
 		setupLog.Error(err, "unable to create controller", "controller", "Standalone")
 		os.Exit(1)
 	}
+
+	// Setup centralized validation webhook for all CRDs
+	if err = enterpriseApi.SetupWebhookWithManager(mgr); err != nil {
+		setupLog.Error(err, "unable to create validation webhook")
+		os.Exit(1)
+	}
 	//+kubebuilder:scaffold:builder
 
 	if err := mgr.AddHealthzCheck("healthz", healthz.Ping); err != nil {

config/certmanager/certificate.yaml

@@ -0,0 +1,38 @@
+# The following manifests contain a self-signed issuer CR and a certificate CR.
+# More document can be found at https://docs.cert-manager.io
+# WARNING: Targets CertManager v1.0. Check https://cert-manager.io/docs/installation/upgrading/ for breaking changes.
+apiVersion: cert-manager.io/v1
+kind: Issuer
+metadata:
+  labels:
+    app.kubernetes.io/name: issuer
+    app.kubernetes.io/instance: selfsigned-issuer
+    app.kubernetes.io/component: certificate
+    app.kubernetes.io/created-by: splunk-operator
+    app.kubernetes.io/part-of: splunk-operator
+    app.kubernetes.io/managed-by: kustomize
+  name: selfsigned-issuer
+  namespace: system
+spec:
+  selfSigned: {}
+---
+apiVersion: cert-manager.io/v1
+kind: Certificate
+metadata:
+  labels:
+    app.kubernetes.io/name: certificate
+    app.kubernetes.io/instance: serving-cert
+    app.kubernetes.io/component: certificate
+    app.kubernetes.io/created-by: splunk-operator
+    app.kubernetes.io/part-of: splunk-operator
+    app.kubernetes.io/managed-by: kustomize
+  name: serving-cert
+  namespace: system
+spec:
+  dnsNames:
+  - $(SERVICE_NAME).$(SERVICE_NAMESPACE).svc
+  - $(SERVICE_NAME).$(SERVICE_NAMESPACE).svc.cluster.local
+  issuerRef:
+    kind: Issuer
+    name: selfsigned-issuer
+  secretName: webhook-server-cert

config/certmanager/kustomization.yaml

@@ -0,0 +1,5 @@
+resources:
+- certificate.yaml
+
+configurations:
+- kustomizeconfig.yaml

config/certmanager/kustomizeconfig.yaml

@@ -0,0 +1,13 @@
+# This configuration is for teaching kustomize how to update name ref and var substitution
+nameReference:
+- kind: Issuer
+  group: cert-manager.io
+  fieldSpecs:
+  - kind: Certificate
+    group: cert-manager.io
+    path: spec/issuerRef/name
+
+varReference:
+- kind: Certificate
+  group: cert-manager.io
+  path: spec/dnsNames

config/default/kustomization.yaml

@@ -20,9 +20,9 @@ bases:
 - ../manager
 # [WEBHOOK] To enable webhook, uncomment all the sections with [WEBHOOK] prefix including the one in
 # crd/kustomization.yaml
-#- ../webhook
+- ../webhook
 # [CERTMANAGER] To enable cert-manager, uncomment all sections with 'CERTMANAGER'. 'WEBHOOK' components are required.
-#- ../certmanager
+- ../certmanager
 # [PROMETHEUS] To enable prometheus monitor, uncomment all sections with 'PROMETHEUS'.
 #- ../prometheus
 # [METRICS] Expose the controller manager metrics service.
@@ -35,42 +35,42 @@ patchesStrategicMerge:
 
 # [WEBHOOK] To enable webhook, uncomment all the sections with [WEBHOOK] prefix including the one in
 # crd/kustomization.yaml
-#- manager_webhook_patch.yaml
+- manager_webhook_patch.yaml
 
 # [CERTMANAGER] To enable cert-manager, uncomment all sections with 'CERTMANAGER'.
 # Uncomment 'CERTMANAGER' sections in crd/kustomization.yaml to enable the CA injection in the admission webhooks.
 # 'CERTMANAGER' needs to be enabled to use ca injection
-#- webhookcainjection_patch.yaml
+- webhookcainjection_patch.yaml
 
 # the following config is for teaching kustomize how to do var substitution
 vars:
 # [CERTMANAGER] To enable cert-manager, uncomment all sections with 'CERTMANAGER' prefix.
-#- name: CERTIFICATE_NAMESPACE # namespace of the certificate CR
-#  objref:
-#    kind: Certificate
-#    group: cert-manager.io
-#    version: v1
-#    name: serving-cert # this name should match the one in certificate.yaml
-#  fieldref:
-#    fieldpath: metadata.namespace
-#- name: CERTIFICATE_NAME
-#  objref:
-#    kind: Certificate
-#    group: cert-manager.io
-#    version: v1
-#    name: serving-cert # this name should match the one in certificate.yaml
-#- name: SERVICE_NAMESPACE # namespace of the service
-#  objref:
-#    kind: Service
-#    version: v1
-#    name: webhook-service
-#  fieldref:
-#    fieldpath: metadata.namespace
-#- name: SERVICE_NAME
-#  objref:
-#    kind: Service
-#    version: v1
-#    name: webhook-service
+- name: CERTIFICATE_NAMESPACE # namespace of the certificate CR
+  objref:
+    kind: Certificate
+    group: cert-manager.io
+    version: v1
+    name: serving-cert # this name should match the one in certificate.yaml
+  fieldref:
+    fieldpath: metadata.namespace
+- name: CERTIFICATE_NAME
+  objref:
+    kind: Certificate
+    group: cert-manager.io
+    version: v1
+    name: serving-cert # this name should match the one in certificate.yaml
+- name: SERVICE_NAMESPACE # namespace of the service
+  objref:
+    kind: Service
+    version: v1
+    name: webhook-service
+  fieldref:
+    fieldpath: metadata.namespace
+- name: SERVICE_NAME
+  objref:
+    kind: Service
+    version: v1
+    name: webhook-service
 
 #patches:
 #- target:

config/default/manager_webhook_patch.yaml

@@ -0,0 +1,23 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: controller-manager
+  namespace: system
+spec:
+  template:
+    spec:
+      containers:
+      - name: manager
+        ports:
+        - containerPort: 9443
+          name: webhook-server
+          protocol: TCP
+        volumeMounts:
+        - mountPath: /tmp/k8s-webhook-server/serving-certs
+          name: cert
+          readOnly: true
+      volumes:
+      - name: cert
+        secret:
+          defaultMode: 420
+          secretName: webhook-server-cert

config/default/webhookcainjection_patch.yaml

@@ -0,0 +1,15 @@
+# This patch add annotation to admission webhook config and
+# the variables $(CERTIFICATE_NAMESPACE) and $(CERTIFICATE_NAME) will be substituted by kustomize.
+apiVersion: admissionregistration.k8s.io/v1
+kind: ValidatingWebhookConfiguration
+metadata:
+  labels:
+    app.kubernetes.io/name: validatingwebhookconfiguration
+    app.kubernetes.io/instance: validating-webhook-configuration
+    app.kubernetes.io/component: webhook
+    app.kubernetes.io/created-by: splunk-operator
+    app.kubernetes.io/part-of: splunk-operator
+    app.kubernetes.io/managed-by: kustomize
+  name: validating-webhook-configuration
+  annotations:
+    cert-manager.io/inject-ca-from: $(CERTIFICATE_NAMESPACE)/$(CERTIFICATE_NAME)

config/webhook/kustomization.yaml

@@ -0,0 +1,6 @@
+resources:
+- manifests.yaml
+- service.yaml
+
+configurations:
+- kustomizeconfig.yaml

config/webhook/kustomizeconfig.yaml

@@ -0,0 +1,25 @@
+# the following config is for teaching kustomize where to look at when substituting vars.
+# It requires kustomize v2.1.0 or newer to work properly.
+nameReference:
+- kind: Service
+  version: v1
+  fieldSpecs:
+  - kind: MutatingWebhookConfiguration
+    group: admissionregistration.k8s.io
+    path: webhooks/clientConfig/service/name
+  - kind: ValidatingWebhookConfiguration
+    group: admissionregistration.k8s.io
+    path: webhooks/clientConfig/service/name
+
+namespace:
+- kind: MutatingWebhookConfiguration
+  group: admissionregistration.k8s.io
+  path: webhooks/clientConfig/service/namespace
+  create: true
+- kind: ValidatingWebhookConfiguration
+  group: admissionregistration.k8s.io
+  path: webhooks/clientConfig/service/namespace
+  create: true
+
+varReference:
+- path: metadata/annotations

config/webhook/manifests.yaml

@@ -0,0 +1,31 @@
+---
+apiVersion: admissionregistration.k8s.io/v1
+kind: ValidatingWebhookConfiguration
+metadata:
+  name: validating-webhook-configuration
+webhooks:
+- admissionReviewVersions:
+  - v1
+  clientConfig:
+    service:
+      name: webhook-service
+      namespace: system
+      path: /validate-splunk-enterprise
+  failurePolicy: Fail
+  name: vsplunk.kb.io
+  rules:
+  - apiGroups:
+    - enterprise.splunk.com
+    apiVersions:
+    - v4
+    operations:
+    - CREATE
+    - UPDATE
+    resources:
+    - standalones
+    - indexerclusters
+    - searchheadclusters
+    - clustermanagers
+    - licensemanagers
+    - monitoringconsoles
+  sideEffects: None

config/webhook/service.yaml

@@ -0,0 +1,12 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: webhook-service
+  namespace: system
+spec:
+  ports:
+  - port: 443
+    protocol: TCP
+    targetPort: 9443
+  selector:
+    control-plane: controller-manager