Merge pull request #4714 from nojnhuh/v2-flag

Add ASOAPI feature flag

Author: k8s-ci-robot

config/manager/manager.yaml

@@ -24,7 +24,7 @@ spec:
             - --leader-elect
             - "--diagnostics-address=${CAPZ_DIAGNOSTICS_ADDRESS:=:8443}"
             - "--insecure-diagnostics=${CAPZ_INSECURE_DIAGNOSTICS:=false}"
-            - "--feature-gates=MachinePool=${EXP_MACHINE_POOL:=false},AKSResourceHealth=${EXP_AKS_RESOURCE_HEALTH:=false},EdgeZone=${EXP_EDGEZONE:=false}"
+            - "--feature-gates=MachinePool=${EXP_MACHINE_POOL:=false},AKSResourceHealth=${EXP_AKS_RESOURCE_HEALTH:=false},EdgeZone=${EXP_EDGEZONE:=false},ASOAPI=${EXP_ASO_API:=false}"
             - "--v=0"
           image: controller:latest
           imagePullPolicy: Always

docs/book/src/topics/aso.md

@@ -79,3 +79,56 @@ More details about how ASO manages CRDs can be found [here](https://azure.github
 
 **Note:** To install the resource for the newly installed CRDs, make sure that the ASO operator has the authentication to install the resources. Refer [authentication in ASO](https://azure.github.io/azure-service-operator/guide/authentication/) for more details.
 An example configuration file and demo for `Azure Cache for Redis` can be found [here](https://github.com/Azure-Samples/azure-service-operator-samples/tree/master/azure-votes-redis).
+
+## Experimental ASO API
+
+CAPZ has begun to experiment with a new flavor of APIs that attempt to address the following limitations of
+the existing CAPZ APIs for advanced use cases:
+
+- A limited set of Azure resource types can be represented.
+- A limited set of Azure resource topologies can be expressed. e.g. Only a single Virtual Network resource can
+  be reconciled for each CAPZ-managed AKS cluster.
+- For each Azure resource type supported by CAPZ, CAPZ generally only uses a single Azure API version to
+  define resources of that type.
+- For each Azure API version known by CAPZ, only a subset of fields defined in that version by the Azure API
+  spec are exposed by the CAPZ API.
+
+This new experimental API defines new AzureASOManagedCluster, AzureASOManagedControlPlane, and
+AzureASOManagedMachinePool resources. An AzureASOManagedCluster might look like this:
+
+```yaml
+apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
+kind: AzureASOManagedCluster
+metadata:
+  name: my-cluster
+  namespace: default
+spec:
+  resources:
+  - apiVersion: resources.azure.com/v1api20200601
+    kind: ResourceGroup
+    metadata:
+      name: my-resource-group
+    spec:
+      location: eastus
+```
+
+The main element of the new API is `spec.resources` in each new resource, which defines arbitrary, literal ASO
+resources inline to be managed by CAPZ. These inline ASO resource definitions take the place of almost all
+other configuration currently defined by CAPZ. e.g. Instead of a CAPZ-specific `spec.location` field on the
+existing AzureManagedControlPlane, the same value would be expected to be set on an ASO ManagedCluster
+resource defined in an AzureASOManagedControlPlane's `spec.resources`. This pattern allows users to define, in
+full, any ASO-supported version of a resource type in any of these new CAPZ resources.
+
+The obvious tradeoff with this new style of API is that CAPZ resource definitions can become more verbose for
+basic use cases. To address this, CAPZ will still offer flavor templates that use this API with all of the
+boilerplate predefined to serve as a starting point for customization.
+
+The overall theme of this API is to leverage ASO as much as possible for representing Azure resources in the
+Kubernetes API, thereby making CAPZ the thinnest possible translation layer between ASO and Cluster API.
+
+This experiment will help inform CAPZ whether this pattern may be a candidate for a potential v2 API. If
+you're interested in trying this out, stay tuned! This functionality is available, but under heavy
+construction and not yet in a usable state, behind the `ASOAPI` feature flag (set by the `EXP_ASO_API`
+environment variable).
+
+Feedback is welcome!

feature/feature.go

@@ -47,6 +47,11 @@ const (
 	// owner: @upxinxin
 	// alpha: v1.8
 	EdgeZone featuregate.Feature = "EdgeZone"
+
+	// ASOAPI is the feature gate for enabling the AzureASO... APIs.
+	// owner: @nojnhuh
+	// alpha: v1.15
+	ASOAPI featuregate.Feature = "ASOAPI"
 )
 
 func init() {
@@ -60,4 +65,5 @@ var defaultCAPZFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
 	AKS:               {Default: true, PreRelease: featuregate.GA, LockToDefault: true}, // Remove in 1.12
 	AKSResourceHealth: {Default: false, PreRelease: featuregate.Alpha},
 	EdgeZone:          {Default: false, PreRelease: featuregate.Alpha},
+	ASOAPI:            {Default: false, PreRelease: featuregate.Alpha},
 }

hack/observability/opentelemetry/controller-manager-patch.yaml

@@ -12,5 +12,5 @@ spec:
             - "--diagnostics-address=:8080"
             - "--insecure-diagnostics"
             - "--leader-elect"
-            - "--feature-gates=MachinePool=${EXP_MACHINE_POOL:=false},AKSResourceHealth=${EXP_AKS_RESOURCE_HEALTH:=false},EdgeZone=${EXP_EDGEZONE:=false}"
+            - "--feature-gates=MachinePool=${EXP_MACHINE_POOL:=false},AKSResourceHealth=${EXP_AKS_RESOURCE_HEALTH:=false},EdgeZone=${EXP_EDGEZONE:=false},ASOAPI=${EXP_ASO_API:=false}"
             - "--enable-tracing"