feat: add ClusterOriginIssuer

When using this controller in single-tenant clusters it becomes
desirable for many users to have a single cluster-scoped issuer rather
than each namespace duplicating the issuers and secrets.

This changeset introduces a "cluster resource namespace", which defaults
to the same namespace as the controller (eg, "origin-ca-issuer"). A
ClusterOriginIssuer resource type has been added which resolves
SecretKeySelectors in this namespace. Other than determing what
namespace to resolve the secret, the implementation is the same as the
existing OriginIssuer.

Fixes: #24

cmd/controller/main.go

@@ -98,13 +98,31 @@ func main() {
 		os.Exit(1)
 	}
 
+	err = builder.
+		ControllerManagedBy(mgr).
+		For(&v1.ClusterOriginIssuer{}).
+		Complete(reconcile.AsReconciler(mgr.GetClient(), &controllers.ClusterOriginIssuerController{
+			Client:                   mgr.GetClient(),
+			Reader:                   mgr.GetAPIReader(),
+			ClusterResourceNamespace: o.ClusterResourceNamespace,
+			Clock:                    clock.RealClock{},
+			Factory:                  f,
+			Log:                      log.WithName("controllers").WithName("ClusterOriginIssuer"),
+		}))
+
+	if err != nil {
+		log.Error(err, "could not create cluster origin issuer controller")
+		os.Exit(1)
+	}
+
 	err = builder.
 		ControllerManagedBy(mgr).
 		For(&certmanager.CertificateRequest{}).
 		Complete(reconcile.AsReconciler(mgr.GetClient(), &controllers.CertificateRequestController{
-			Client: mgr.GetClient(),
-			Reader: mgr.GetAPIReader(),
-			Log:    log.WithName("controllers").WithName("CertificateRequest"),
+			Client:                   mgr.GetClient(),
+			Reader:                   mgr.GetAPIReader(),
+			ClusterResourceNamespace: o.ClusterResourceNamespace,
+			Log:                      log.WithName("controllers").WithName("CertificateRequest"),
 
 			Clock:                  clock.RealClock{},
 			CheckApprovedCondition: !o.DisableApprovedCheck,

cmd/controller/options/options.go

@@ -7,8 +7,9 @@ import (
 )
 
 type ControllerOptions struct {
-	KubernetesAPIQPS   float32
-	KubernetesAPIBurst int
+	KubernetesAPIQPS         float32
+	KubernetesAPIBurst       int
+	ClusterResourceNamespace string
 
 	DisableApprovedCheck bool
 }
@@ -29,6 +30,7 @@ func (o *ControllerOptions) AddFlags(fs *pflag.FlagSet) {
 	fs.Float32Var(&o.KubernetesAPIQPS, "kube-api-qps", defaultKubernetesAPIQPS, "Maximium queries-per-second of requests to the Kubernetes apiserver.")
 	fs.IntVar(&o.KubernetesAPIBurst, "kube-api-burst", defaultKubernetesAPIBurst, "Maximium queries-per-second burst of request send to the Kubernetes apiserver.")
 	fs.BoolVar(&o.DisableApprovedCheck, "disable-approved-check", o.DisableApprovedCheck, "Disables waiting for CertificateRequests to have an approved condition before signing.")
+	fs.StringVar(&o.ClusterResourceNamespace, "cluster-resource-namespace", o.ClusterResourceNamespace, "Namespace used for cluster-scoped resources, such as secrets used by ClusterOriginIssuer")
 }
 
 func (o *ControllerOptions) Validate() error {
@@ -40,5 +42,9 @@ func (o *ControllerOptions) Validate() error {
 		return fmt.Errorf("invalid value for kube-api-qps: %v must be higher than 0", o.KubernetesAPIQPS)
 	}
 
+	if o.ClusterResourceNamespace == "" {
+		return fmt.Errorf("invalid value for cluster-resource-namespace: must be set")
+	}
+
 	return nil
 }

deploy/crds/cert-manager.k8s.cloudflare.com_clusteroriginissuers.yaml

@@ -0,0 +1,119 @@
+---
+apiVersion: apiextensions.k8s.io/v1
+kind: CustomResourceDefinition
+metadata:
+  annotations:
+    controller-gen.kubebuilder.io/version: v0.13.0
+  name: clusteroriginissuers.cert-manager.k8s.cloudflare.com
+spec:
+  group: cert-manager.k8s.cloudflare.com
+  names:
+    kind: ClusterOriginIssuer
+    listKind: ClusterOriginIssuerList
+    plural: clusteroriginissuers
+    singular: clusteroriginissuer
+  scope: Cluster
+  versions:
+  - name: v1
+    schema:
+      openAPIV3Schema:
+        description: A ClusterOriginIssuer represents the Cloudflare Origin CA as
+          an external cert-manager issuer. It is scoped to a single namespace, so
+          it can be used only by resources in the same namespace.
+        properties:
+          apiVersion:
+            description: 'APIVersion defines the versioned schema of this representation
+              of an object. Servers should convert recognized schemas to the latest
+              internal value, and may reject unrecognized values. More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resources'
+            type: string
+          kind:
+            description: 'Kind is a string value representing the REST resource this
+              object represents. Servers may infer this from the endpoint the client
+              submits requests to. Cannot be updated. In CamelCase. More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds'
+            type: string
+          metadata:
+            type: object
+          spec:
+            description: Spec is the desired state of the ClusterOriginIssuer resource.
+            properties:
+              auth:
+                description: Auth configures how to authenticate with the Cloudflare
+                  API.
+                properties:
+                  serviceKeyRef:
+                    description: ServiceKeyRef authenticates with an API Service Key.
+                    properties:
+                      key:
+                        description: Key of the secret to select from. Must be a valid
+                          secret key.
+                        type: string
+                      name:
+                        description: Name of the secret in the issuer's namespace
+                          to select. If a cluster-scoped issuer, the secret is selected
+                          from the "cluster resource namespace" configured on the
+                          controller.
+                        type: string
+                    required:
+                    - key
+                    - name
+                    type: object
+                type: object
+              requestType:
+                description: RequestType is the signature algorithm Cloudflare should
+                  use to sign the certificate.
+                enum:
+                - OriginRSA
+                - OriginECC
+                type: string
+            required:
+            - auth
+            - requestType
+            type: object
+          status:
+            description: Status of the ClusterOriginIssuer. This is set and managed
+              automatically.
+            properties:
+              conditions:
+                description: List of status conditions to indicate the status of an
+                  OriginIssuer Known condition types are `Ready`.
+                items:
+                  description: OriginIssuerCondition contains condition information
+                    for the OriginIssuer.
+                  properties:
+                    lastTransitionTime:
+                      description: LastTransitionTime is the timestamp corresponding
+                        to the last status change of this condition.
+                      format: date-time
+                      type: string
+                    message:
+                      description: Message is a human readable description of the
+                        details of the last transition1, complementing reason.
+                      type: string
+                    reason:
+                      description: Reason is a brief machine readable explanation
+                        for the condition's last transition.
+                      type: string
+                    status:
+                      description: Status of the condition, one of ('True', 'False',
+                        'Unknown')
+                      enum:
+                      - "True"
+                      - "False"
+                      - Unknown
+                      type: string
+                    type:
+                      description: Type of the condition, known values are ('Ready')
+                      enum:
+                      - Ready
+                      type: string
+                  required:
+                  - status
+                  - type
+                  type: object
+                type: array
+            type: object
+        type: object
+    served: true
+    storage: true
+    subresources:
+      status: {}

deploy/crds/cert-manager.k8s.cloudflare.com_originissuers.yaml

@@ -48,8 +48,10 @@ spec:
                           secret key.
                         type: string
                       name:
-                        description: Name of the secret in the OriginIssuer's namespace
-                          to select from.
+                        description: Name of the secret in the issuer's namespace
+                          to select. If a cluster-scoped issuer, the secret is selected
+                          from the "cluster resource namespace" configured on the
+                          controller.
                         type: string
                     required:
                     - key

deploy/manifests/deployment.yaml

@@ -15,8 +15,10 @@ spec:
     spec:
       serviceAccountName: originissuer-control
       containers:
-        - image: cloudflare/origin-ca-issuer:v0.8.0
-          name: origin-ca-controller
+        - name: origin-ca-controller
+          image: cloudflare/origin-ca-issuer:v0.8.0
+          args:
+            - --cluster-resource-namespace=origin-ca-issuer
           resources:
             limits:
               cpu: "1"

pkgs/apis/v1/doc.go

@@ -23,5 +23,5 @@ var (
 )
 
 func init() {
-	SchemeBuilder.Register(&OriginIssuer{}, &OriginIssuerList{})
+	SchemeBuilder.Register(&OriginIssuer{}, &OriginIssuerList{}, &ClusterOriginIssuer{}, &ClusterOriginIssuerList{})
 }

pkgs/apis/v1/types_originissuer.go

@@ -32,6 +32,35 @@ type OriginIssuerList struct {
 	Items []OriginIssuer `json:"items"`
 }
 
+// +kubebuilder:object:root=true
+// +kubebuilder:resource:scope=Cluster
+// +kubebuilder:subresource:status
+
+// A ClusterOriginIssuer represents the Cloudflare Origin CA as an external cert-manager issuer.
+// It is scoped to a single namespace, so it can be used only by resources in the same
+// namespace.
+type ClusterOriginIssuer struct {
+	metav1.TypeMeta   `json:",inline"`
+	metav1.ObjectMeta `json:"metadata,omitempty"`
+
+	// Spec is the desired state of the ClusterOriginIssuer resource.
+	Spec OriginIssuerSpec `json:"spec,omitempty"`
+
+	// Status of the ClusterOriginIssuer. This is set and managed automatically.
+	// +optional
+	Status OriginIssuerStatus `json:"status,omitempty"`
+}
+
+// +kubebuilder:object:root=true
+
+// ClusterOriginIssuerList is a list of OriginIssuers.
+type ClusterOriginIssuerList struct {
+	metav1.TypeMeta `json:",inline"`
+	metav1.ListMeta `json:"metadata.omitempty"`
+
+	Items []ClusterOriginIssuer `json:"items"`
+}
+
 // OriginIssuerSpec is the specification of an OriginIssuer. This includes any
 // configuration required for the issuer.
 type OriginIssuerSpec struct {
@@ -60,7 +89,9 @@ type OriginIssuerAuthentication struct {
 
 // SecretKeySelector contains a reference to a secret.
 type SecretKeySelector struct {
-	// Name of the secret in the OriginIssuer's namespace to select from.
+	// Name of the secret in the issuer's namespace to select. If a cluster-scoped
+	// issuer, the secret is selected from the "cluster resource namespace" configured
+	// on the controller.
 	Name string `json:"name"`
 	// Key of the secret to select from. Must be a valid secret key.
 	Key string `json:"key"`