FleetAutoscaler can be targeted at Non Existent Fleets

This removes some previous restrictions with the FleetAutoscaler,
as well as cleaning up a couple of items.

- FleetAutoscalers can now have a Fleet target that doesn't exit.
  - If the target doesn't exist, this will be recorded as a warning event
    of type `FailedGetFleet`, rather than `ScalingLimited` status item,
    as it allows a human readable message, as well as give us data on how
    often this occurs, and it is readable by stat/alerting packages.
- FleetAutoscalers can now have their Fleet target edited. This
  means that FleetAutoscalers can be transitioned from one Fleet
  to another. This may be useful in scenarios like red-green deployments, or
  if you wish to temporarily disable an Autoscaler, but not delete it.
- `FleetAutoscaler.Status.ScalingLimited` was also replaced by a `ScalingLimited`
  Event, as it allows a human readable message, as well as give us data on how
  often this occurs, and it is readable by stat/alerting packages.

Closes #406

install/helm/agones/templates/admissionregistration.yaml

@@ -86,7 +86,6 @@ webhooks:
           - "gameservers"
           - "fleets"
           - "fleetallocations"
-          - "fleetautoscalers"
         apiVersions:
           - "v1alpha1"
         operations:

install/yaml/install.yaml

@@ -925,7 +925,6 @@ webhooks:
           - "gameservers"
           - "fleets"
           - "fleetallocations"
-          - "fleetautoscalers"
         apiVersions:
           - "v1alpha1"
         operations:

pkg/apis/stable/v1alpha1/fleetautoscaler.go

@@ -102,37 +102,17 @@ type FleetAutoscalerStatus struct {
 	// lastScaleTime is the last time the FleetAutoscaler scaled the attached fleet,
 	// +optional
 	LastScaleTime *metav1.Time `json:"lastScaleTime"`
-
-	// AbleToScale indicates that we can access the target fleet
-	AbleToScale bool `json:"ableToScale"`
-
-	// ScalingLimited indicates that the calculated scale would be above or below the range
-	// defined by MinReplicas and MaxReplicas, and has thus been capped.
-	ScalingLimited bool `json:"scalingLimited"`
-}
-
-// ValidateUpdate validates when an update occurs
-func (fas *FleetAutoscaler) ValidateUpdate(new *FleetAutoscaler, causes []metav1.StatusCause) []metav1.StatusCause {
-	if fas.Spec.FleetName != new.Spec.FleetName {
-		causes = append(causes, metav1.StatusCause{
-			Type:    metav1.CauseTypeFieldValueInvalid,
-			Field:   "fleetName",
-			Message: "fleetName cannot be updated",
-		})
-	}
-
-	return new.ValidateAutoScalingSettings(causes)
 }
 
-//ValidateAutoScalingSettings validates the FleetAutoscaler scaling settings
-func (fas *FleetAutoscaler) ValidateAutoScalingSettings(causes []metav1.StatusCause) []metav1.StatusCause {
+// Validate validates the FleetAutoscaler scaling settings
+func (fas *FleetAutoscaler) Validate(causes []metav1.StatusCause) []metav1.StatusCause {
 	if fas.Spec.Policy.Type == BufferPolicyType {
 		causes = fas.Spec.Policy.Buffer.ValidateAutoScalingBufferPolicy(causes)
 	}
 	return causes
 }
 
-//ValidateAutoScalingSettings validates the FleetAutoscaler Buffer policy settings
+// ValidateAutoScalingBufferPolicy validates the FleetAutoscaler Buffer policy settings
 func (b *BufferPolicy) ValidateAutoScalingBufferPolicy(causes []metav1.StatusCause) []metav1.StatusCause {
 	if b == nil {
 		return append(causes, metav1.StatusCause{

pkg/apis/stable/v1alpha1/fleetautoscaler_test.go

@@ -25,209 +25,93 @@ import (
 func TestFleetAutoscalerValidateUpdate(t *testing.T) {
 	t.Parallel()
 
-	t.Run("same fleet name", func(t *testing.T) {
-
-		fas := &FleetAutoscaler{
-			ObjectMeta: metav1.ObjectMeta{Name: "test"},
-			Spec: FleetAutoscalerSpec{
-				FleetName: "testing",
-				Policy: FleetAutoscalerPolicy{
-					Type: BufferPolicyType,
-					Buffer: &BufferPolicy{
-						BufferSize:  intstr.FromInt(1),
-						MaxReplicas: 10,
-					},
-				},
-			},
-		}
-
-		causes := fas.ValidateUpdate(fas.DeepCopy(), nil)
-		assert.Len(t, causes, 0)
-	})
-
-	t.Run("different fleet name", func(t *testing.T) {
-
-		fas := &FleetAutoscaler{
-			ObjectMeta: metav1.ObjectMeta{Name: "test"},
-			Spec: FleetAutoscalerSpec{
-				FleetName: "testing",
-				Policy: FleetAutoscalerPolicy{
-					Type: BufferPolicyType,
-					Buffer: &BufferPolicy{
-						BufferSize:  intstr.FromInt(1),
-						MaxReplicas: 10,
-					},
-				},
-			},
-		}
-		fasCopy := fas.DeepCopy()
-		fasCopy.Spec.FleetName = "notthesame"
-
-		causes := fas.ValidateUpdate(fasCopy, nil)
-
-		assert.Len(t, causes, 1)
-		assert.Equal(t, "fleetName", causes[0].Field)
-	})
-
 	t.Run("bad buffer size", func(t *testing.T) {
-
-		fas := &FleetAutoscaler{
-			ObjectMeta: metav1.ObjectMeta{Name: "test"},
-			Spec: FleetAutoscalerSpec{
-				FleetName: "testing",
-				Policy: FleetAutoscalerPolicy{
-					Type: BufferPolicyType,
-					Buffer: &BufferPolicy{
-						BufferSize:  intstr.FromInt(1),
-						MaxReplicas: 10,
-					},
-				},
-			},
-		}
-
-		fasCopy := fas.DeepCopy()
-		fasCopy.Spec.Policy.Buffer.BufferSize = intstr.FromInt(0)
-
-		causes := fas.ValidateUpdate(fasCopy, nil)
+		fas := defaultFixture()
+		fas.Spec.Policy.Buffer.BufferSize = intstr.FromInt(0)
+		causes := fas.Validate(nil)
 
 		assert.Len(t, causes, 1)
 		assert.Equal(t, "bufferSize", causes[0].Field)
 	})
 
 	t.Run("bad min replicas", func(t *testing.T) {
 
-		fas := &FleetAutoscaler{
-			ObjectMeta: metav1.ObjectMeta{Name: "test"},
-			Spec: FleetAutoscalerSpec{
-				FleetName: "testing",
-				Policy: FleetAutoscalerPolicy{
-					Type: BufferPolicyType,
-					Buffer: &BufferPolicy{
-						BufferSize:  intstr.FromInt(5),
-						MaxReplicas: 10,
-					},
-				},
-			},
-		}
-
-		fasCopy := fas.DeepCopy()
-		fasCopy.Spec.Policy.Buffer.MinReplicas = 2
+		fas := defaultFixture()
+		fas.Spec.Policy.Buffer.MinReplicas = 2
 
-		causes := fas.ValidateUpdate(fasCopy, nil)
+		causes := fas.Validate(nil)
 
 		assert.Len(t, causes, 1)
 		assert.Equal(t, "minReplicas", causes[0].Field)
 	})
 
 	t.Run("bad max replicas", func(t *testing.T) {
-
-		fas := &FleetAutoscaler{
-			ObjectMeta: metav1.ObjectMeta{Name: "test"},
-			Spec: FleetAutoscalerSpec{
-				FleetName: "testing",
-				Policy: FleetAutoscalerPolicy{
-					Type: BufferPolicyType,
-					Buffer: &BufferPolicy{
-						BufferSize:  intstr.FromInt(5),
-						MaxReplicas: 10,
-					},
-				},
-			},
-		}
-
-		fasCopy := fas.DeepCopy()
-		fasCopy.Spec.Policy.Buffer.MaxReplicas = 2
-		causes := fas.ValidateUpdate(fasCopy, nil)
+		fas := defaultFixture()
+		fas.Spec.Policy.Buffer.MaxReplicas = 2
+		causes := fas.Validate(nil)
 
 		assert.Len(t, causes, 1)
 		assert.Equal(t, "maxReplicas", causes[0].Field)
 	})
 
 	t.Run("minReplicas > maxReplicas", func(t *testing.T) {
-
-		fas := &FleetAutoscaler{
-			ObjectMeta: metav1.ObjectMeta{Name: "test"},
-			Spec: FleetAutoscalerSpec{
-				FleetName: "testing",
-				Policy: FleetAutoscalerPolicy{
-					Type: BufferPolicyType,
-					Buffer: &BufferPolicy{
-						BufferSize:  intstr.FromInt(5),
-						MaxReplicas: 10,
-					},
-				},
-			},
-		}
-
-		fasCopy := fas.DeepCopy()
-		fasCopy.Spec.Policy.Buffer.MinReplicas = 20
-		causes := fas.ValidateUpdate(fasCopy, nil)
+		fas := defaultFixture()
+		fas.Spec.Policy.Buffer.MinReplicas = 20
+		causes := fas.Validate(nil)
 
 		assert.Len(t, causes, 1)
 		assert.Equal(t, "minReplicas", causes[0].Field)
 	})
 
 	t.Run("bufferSize good percent", func(t *testing.T) {
-
-		fas := &FleetAutoscaler{
-			ObjectMeta: metav1.ObjectMeta{Name: "test"},
-			Spec: FleetAutoscalerSpec{
-				FleetName: "testing",
-				Policy: FleetAutoscalerPolicy{
-					Type: BufferPolicyType,
-					Buffer: &BufferPolicy{
-						BufferSize:  intstr.FromInt(5),
-						MaxReplicas: 10,
-					},
-				},
-			},
-		}
-
-		fasCopy := fas.DeepCopy()
-		fasCopy.Spec.Policy.Buffer.BufferSize = intstr.FromString("20%")
-		causes := fas.ValidateUpdate(fasCopy, nil)
+		fas := defaultFixture()
+		fas.Spec.Policy.Buffer.BufferSize = intstr.FromString("20%")
+		causes := fas.Validate(nil)
 
 		assert.Len(t, causes, 0)
 	})
 
 	t.Run("bufferSize bad percent", func(t *testing.T) {
-
-		fas := &FleetAutoscaler{
-			ObjectMeta: metav1.ObjectMeta{Name: "test"},
-			Spec: FleetAutoscalerSpec{
-				FleetName: "testing",
-				Policy: FleetAutoscalerPolicy{
-					Type: BufferPolicyType,
-					Buffer: &BufferPolicy{
-						BufferSize:  intstr.FromInt(5),
-						MaxReplicas: 10,
-					},
-				},
-			},
-		}
+		fas := defaultFixture()
 
 		fasCopy := fas.DeepCopy()
 		fasCopy.Spec.Policy.Buffer.BufferSize = intstr.FromString("120%")
-		causes := fas.ValidateUpdate(fasCopy, nil)
+		causes := fasCopy.Validate(nil)
 		assert.Len(t, causes, 1)
 		assert.Equal(t, "bufferSize", causes[0].Field)
 
 		fasCopy = fas.DeepCopy()
 		fasCopy.Spec.Policy.Buffer.BufferSize = intstr.FromString("0%")
-		causes = fas.ValidateUpdate(fasCopy, nil)
+		causes = fasCopy.Validate(nil)
 		assert.Len(t, causes, 1)
 		assert.Equal(t, "bufferSize", causes[0].Field)
 
 		fasCopy = fas.DeepCopy()
 		fasCopy.Spec.Policy.Buffer.BufferSize = intstr.FromString("-10%")
-		causes = fas.ValidateUpdate(fasCopy, nil)
+		causes = fasCopy.Validate(nil)
 		assert.Len(t, causes, 1)
 		assert.Equal(t, "bufferSize", causes[0].Field)
 		fasCopy = fas.DeepCopy()
 
 		fasCopy.Spec.Policy.Buffer.BufferSize = intstr.FromString("notgood")
-		causes = fas.ValidateUpdate(fasCopy, nil)
+		causes = fasCopy.Validate(nil)
 		assert.Len(t, causes, 1)
 		assert.Equal(t, "bufferSize", causes[0].Field)
 	})
 }
+
+func defaultFixture() *FleetAutoscaler {
+	return &FleetAutoscaler{
+		ObjectMeta: metav1.ObjectMeta{Name: "test"},
+		Spec: FleetAutoscalerSpec{
+			FleetName: "testing",
+			Policy: FleetAutoscalerPolicy{
+				Type: BufferPolicyType,
+				Buffer: &BufferPolicy{
+					BufferSize:  intstr.FromInt(5),
+					MaxReplicas: 10,
+				},
+			},
+		},
+	}
+}