[datadogpodautoscalers] Add local fallback policy (#1759)

* Fix missing apostrophe in dpa json

* Add fallback policy and types

* Generate files

* Fix typo in apply policy name

* Use new fallback policy type

* Update fallback policy to only expose necessary options

* Update comment to reflect how pod resource objectives are defined

* Use bool for enabling fallback to reflect binary option

* fixup! Use bool for enabling fallback to reflect binary option

* Use fallback as top level for flexibility to add other fallback modes in future

Author: jennchenn

api/datadoghq/v1alpha2/datadogpodautoscaler_types.go

@@ -36,7 +36,7 @@ import (
 //           periodSeconds: 60
 //   objectives:
 //     - type: PodResource
-//       resource:
+//       podResource:
 //         name: cpu
 //         value:
 //           type: Absolute|Utilization
@@ -49,6 +49,11 @@ import (
 //           type: Absolute|Utilization
 //           absolute: 500m
 //           utilization: 80
+//   fallback:
+// 	   horizontal:
+//       enabled: true
+//       triggers:
+//         staleRecommendationThresholdSeconds: 600
 //   constraints:
 //     minReplicas: 1
 //     maxReplicas: 10
@@ -83,6 +88,11 @@ type DatadogPodAutoscalerSpec struct {
 	// +kubebuilder:validation:MinItems=1
 	Objectives []common.DatadogPodAutoscalerObjective `json:"objectives,omitempty"`
 
+	// Fallback defines how recommendations should be applied when in fallback mode.
+	// +optional
+	// +kubebuilder:default={}
+	Fallback *DatadogFallbackPolicy `json:"fallback,omitempty"`
+
 	// Constraints defines constraints that should always be respected.
 	Constraints *common.DatadogPodAutoscalerConstraints `json:"constraints,omitempty"`
 }
@@ -119,6 +129,37 @@ type DatadogPodAutoscalerApplyPolicy struct {
 	ScaleDown *common.DatadogPodAutoscalerScalingPolicy `json:"scaleDown,omitempty"`
 }
 
+// DatadogFallbackPolicy configures the behavior during fallback mode.
+type DatadogFallbackPolicy struct {
+	// Horizontal configures the behavior during horizontal fallback mode.
+	// +optional
+	// +kubebuilder:default={}
+	Horizontal DatadogPodAutoscalerHorizontalFallbackPolicy `json:"horizontal,omitempty"`
+}
+
+// DatadogPodAutoscalerHorizontalFallbackPolicy defines how recommendations should be applied in fallback mode.
+type DatadogPodAutoscalerHorizontalFallbackPolicy struct {
+	// Enabled determines whether recommendations should be applied by the controller:
+	// +optional
+	// +kubebuilder:default=true
+	Enabled bool `json:"enabled"`
+
+	// Triggers defines the triggers that will generate recommendations.
+	// +optional
+	// +kubebuilder:default={}
+	Triggers HorizontalFallbackTriggers `json:"triggers,omitempty"`
+}
+
+// HorizontalFallbackTriggers defines the triggers that will cause local fallback to be enabled.
+type HorizontalFallbackTriggers struct {
+	// StaleRecommendationThresholdSeconds defines the time window the controller will wait after detecting an error before applying recommendations.
+	// +optional
+	// +kubebuilder:default=600
+	// +kubebuilder:validation:Minimum=100
+	// +kubebuilder:validation:Maximum=1200
+	StaleRecommendationThresholdSeconds int32 `json:"staleRecommendationThresholdSeconds,omitempty"`
+}
+
 // +kubebuilder:object:root=true
 // +kubebuilder:resource:shortName=dpa
 // +kubebuilder:subresource:status

api/datadoghq/v1alpha2/zz_generated.deepcopy.go

@@ -819,6 +819,32 @@ spec:
                   required:
                     - maxReplicas
                   type: object
+                fallback:
+                  default: {}
+                  description: Fallback defines how recommendations should be applied when in fallback mode.
+                  properties:
+                    horizontal:
+                      default: {}
+                      description: Horizontal configures the behavior during horizontal fallback mode.
+                      properties:
+                        enabled:
+                          default: true
+                          description: 'Enabled determines whether recommendations should be applied by the controller:'
+                          type: boolean
+                        triggers:
+                          default: {}
+                          description: Triggers defines the triggers that will generate recommendations.
+                          properties:
+                            staleRecommendationThresholdSeconds:
+                              default: 600
+                              description: StaleRecommendationThresholdSeconds defines the time window the controller will wait after detecting an error before applying recommendations.
+                              format: int32
+                              maximum: 1200
+                              minimum: 100
+                              type: integer
+                          type: object
+                      type: object
+                  type: object
                 objectives:
                   description: |-
                     Objectives are the objectives to reach and maintain for the target resource.

config/crd/bases/v1/datadoghq.com_datadogpodautoscalers.yaml

@@ -279,6 +279,43 @@
           ],
           "type": "object"
         },
+        "fallback": {
+          "additionalProperties": false,
+          "default": {},
+          "description": "Fallback defines how recommendations should be applied when in fallback mode.",
+          "properties": {
+            "horizontal": {
+              "additionalProperties": false,
+              "default": {},
+              "description": "Horizontal configures the behavior during horizontal fallback mode.",
+              "properties": {
+                "enabled": {
+                  "default": true,
+                  "description": "Enabled determines whether recommendations should be applied by the controller:",
+                  "type": "boolean"
+                },
+                "triggers": {
+                  "additionalProperties": false,
+                  "default": {},
+                  "description": "Triggers defines the triggers that will generate recommendations.",
+                  "properties": {
+                    "staleRecommendationThresholdSeconds": {
+                      "default": 600,
+                      "description": "StaleRecommendationThresholdSeconds defines the time window the controller will wait after detecting an error before applying recommendations.",
+                      "format": "int32",
+                      "maximum": 1200,
+                      "minimum": 100,
+                      "type": "integer"
+                    }
+                  },
+                  "type": "object"
+                }
+              },
+              "type": "object"
+            }
+          },
+          "type": "object"
+        },
         "objectives": {
           "description": "Objectives are the objectives to reach and maintain for the target resource.\nDefault to a single objective to maintain 80% POD CPU utilization.",
           "items": {

config/crd/bases/v1/datadoghq.com_datadogpodautoscalers_v1alpha2.json

@@ -1,5 +1,5 @@
 {
-  description": "DatadogPodAutoscaler is the Schema for the datadogpodautoscalers API",
+  "description": "DatadogPodAutoscaler is the Schema for the datadogpodautoscalers API",
   "properties": {
     "apiVersion": {
       "description": "APIVersion defines the versioned schema of this representation of an object.\nServers should convert recognized schemas to the latest internal value, and\nmay reject unrecognized values.\nMore info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resources",