Merge pull request #375 from zalando-incubator/kube1.21

Upgrade Kubernetes and its friends to 1.21

README.md

@@ -306,20 +306,27 @@ for this object. But to satisfy the schema we specify a dummy pod called `dummy-
 ## Skipper collector
 
 The skipper collector is a simple wrapper around the Prometheus collector to
-make it easy to define an HPA for scaling based on ingress metrics when
+make it easy to define an HPA for scaling based on [Ingress][ingress] or
+[RouteGroup][routegroup] metrics when
 [skipper](https://github.com/zalando/skipper) is used as the ingress
 implementation in your cluster. It assumes you are collecting Prometheus
 metrics from skipper and it provides the correct Prometheus queries out of the
 box so users don't have to define those manually.
 
+[ingress]: https://kubernetes.io/docs/concepts/services-networking/ingress/
+[routegroup]: https://opensource.zalando.com/skipper/kubernetes/routegroups/
+
 ### Supported metrics
 
 | Metric | Description | Type | Kind | K8s Versions |
 | ----------- | -------------- | ------ | ---- | ---- |
-| `requests-per-second` | Scale based on requests per second for a certain ingress. | Object | `Ingress` | `>=1.14` |
+| `requests-per-second` | Scale based on requests per second for a certain ingress or routegroup. | Object | `Ingress`, `RouteGroup` | `>=1.14` |
 
 ### Example
 
+
+#### Ingress
+
 This is an example of an HPA that will scale based on `requests-per-second` for
 an ingress called `myapp`.
 
@@ -339,11 +346,48 @@ spec:
   - type: Object
     object:
       describedObject:
-        apiVersion: extensions/v1beta1
+        apiVersion: networking.k8s.io/v1
         kind: Ingress
         name: myapp
       metric:
         name: requests-per-second
+        selector:
+          matchLabels:
+            backend: backend1 # optional backend
+      target:
+        averageValue: "10"
+        type: AverageValue
+```
+
+#### RouteGroup
+
+This is an example of an HPA that will scale based on `requests-per-second` for
+a routegroup called `myapp`.
+
+```yaml
+apiVersion: autoscaling/v2beta2
+kind: HorizontalPodAutoscaler
+metadata:
+  name: myapp-hpa
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: myapp
+  minReplicas: 1
+  maxReplicas: 10
+  metrics:
+  - type: Object
+    object:
+      describedObject:
+        apiVersion: zalando.org/v1
+        kind: RouteGroup
+        name: myapp
+      metric:
+        name: requests-per-second
+        selector:
+          matchLabels:
+            backend: backend1 # optional backend
       target:
         averageValue: "10"
         type: AverageValue
@@ -351,15 +395,14 @@ spec:
 
 ### Metric weighting based on backend
 
-Skipper supports sending traffic to different backend based on annotations
-present on the `Ingress` object. When the metric name is specified without a
-backend as `requests-per-second` then the number of replicas will be calculated
-based on the full traffic served by that ingress.  If however only the traffic
-being routed to a specific backend should be used then the backend name can be
-specified as a metric name like `requests-per-second,backend1` which would
-return the requests-per-second being sent to the `backend1`. The ingress
-annotation where the backend weights can be obtained can be specified through
-the flag `--skipper-backends-annotation`.
+Skipper supports sending traffic to different backends based on annotations
+present on the `Ingress` object, or weights on the RouteGroup backends. By
+default the number of replicas will be calculated based on the full traffic
+served by that ingress/routegroup.  If however only the traffic being routed to
+a specific backend should be used then the backend name can be specified via
+the `backend` label under `matchLabels` for the metric.  The ingress annotation
+where the backend weights can be obtained can be specified through the flag
+`--skipper-backends-annotation`.
 
 ## InfluxDB collector
 
@@ -677,12 +720,63 @@ The `ScalingSchedule` and `ClusterScalingSchedule` collectors allow
 collecting time-based metrics from the respective CRD objects specified
 in the HPA.
 
+These collectors are disabled by default, you have to start the server
+with the `--scaling-schedule` flag to enable it. Remember to deploy the CRDs
+`ScalingSchedule` and `ClusterScalingSchedule` and allow the service
+account used by the server to read, watch and list them.
+
 ### Supported metrics
 
 | Metric | Description | Type | K8s Versions |
 | ---------- | -------------- | ------- | -- |
 | ObjectName | The metric is calculated and stored for each `ScalingSchedule` and `ClusterScalingSchedule` referenced in the HPAs | `ScalingSchedule` and `ClusterScalingSchedule` | `>=1.16` |
 
+### Ramp-up and ramp-down feature
+
+To avoid abrupt scaling due to time based metrics,the `SchalingSchedule`
+collector has a feature of ramp-up and ramp-down the metric over a
+specific period of time. The duration of the scaling window can be
+configured individually in the `[Cluster]ScalingSchedule` object, via
+the option `scalingWindowDurationMinutes` or globally for all scheduled
+events, and defaults to a globally configured value if not specified.
+The default for the latter is set to 10 minutes, but can be changed
+using the `--scaling-schedule-default-scaling-window` flag.
+
+This spreads the scale events around, creating less load on the other
+components, and helping the rest of the metrics (like the CPU ones) to
+adjust as well.
+
+The [HPA algorithm][algo-details] does not make changes if the metric
+change is less than the specified by the
+`horizontal-pod-autoscaler-tolerance` flag:
+
+> We'll skip scaling if the ratio is sufficiently close to 1.0 (within a
+> globally-configurable tolerance, from the
+> `--horizontal-pod-autoscaler-tolerance` flag, which defaults to 0.1.
+
+With that in mind, the ramp-up and ramp-down feature divides the scaling
+over the specified period of time in buckets, trying to achieve changes
+bigger than the configured tolerance. The number of buckets defaults to
+10 and can be configured by the `--scaling-schedule-ramp-steps` flag.
+
+**Important**: note that the ramp-up and ramp-down feature can lead to
+deployments achieving less than the specified number of pods, due to the
+HPA 10% change rule and the ceiling function applied to the desired
+number of the pods (check the [algorithm details][algo-details]). It
+varies with the configured metric for `ScalingSchedule` events, the
+number of pods and the configured `horizontal-pod-autoscaler-tolerance`
+flag of your kubernetes installation. [This gist][gist] contains the code to
+simulate the situations a deployment with different number of pods, with
+a metric of 10000 can face with 10 buckets (max of 90% of the metric
+returned) and 5 buckets (max of 80% of the metric returned). The ramp-up
+and ramp-down feature can be disabled by setting
+`--scaling-schedule-default-scaling-window` to 0 and abrupt scalings can
+be handled via [scaling policies][policies].
+
+[algo-details]: https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/#algorithm-details
+[gist]: https://gist.github.com/jonathanbeber/37f1f918ab7ef6101c6ce56cc2cef3a2
+[policies]: https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/#scaling-policies
+
 ### Example
 
 This is an example of using the ScalingSchedule collectors to collect
@@ -783,8 +877,3 @@ Note that these number of pods are just considering these custom
 metrics, the normal HPA behavior still applies, such as: in case of
 multiple metrics the biggest number of pods is the utilized one, HPA max
 and min replica configuration, autoscaling policies, etc.
-
-These collectors are disabled by default, you have to start the server
-with the `--scaling-schedule` flag to enable it. Remember to deploy the CRDs
-`ScalingSchedule` and `ClusterScalingSchedule` and allow the service
-account used by the server to read, watch and list them.

docs/cluster_scaling_schedules_crd.yaml

@@ -37,6 +37,11 @@ spec:
           spec:
             description: ScalingScheduleSpec is the spec part of the ScalingSchedule.
             properties:
+              scalingWindowDurationMinutes:
+                description: Fade the scheduled values in and out over this many minutes.
+                  If unset, the default per-cluster value will be used.
+                format: int64
+                type: integer
               schedules:
                 description: Schedules is the list of schedules for this ScalingSchedule
                   resource. All the schedules defined here will result on the value
@@ -96,6 +101,7 @@ spec:
                     value:
                       description: The metric value that will be returned for the
                         defined schedule.
+                      format: int64
                       type: integer
                   required:
                   - durationMinutes

docs/rbac.yaml

@@ -64,12 +64,23 @@ rules:
   - statefulsets
   verbs:
   - get
+# only relevant if running with the flag:
+# --skipper-ingress-metrics
 - apiGroups:
   - extensions
+  - networking.k8s.io
   resources:
   - ingresses
   verbs:
   - get
+# only relevant if running with the flag:
+# --skipper-routegroup-metrics
+- apiGroups:
+  - zalando.org
+  resources:
+  - routegroups
+  verbs:
+  - get
 - apiGroups:
   - autoscaling
   resources:

docs/scaling_schedules_crd.yaml

@@ -37,6 +37,11 @@ spec:
           spec:
             description: ScalingScheduleSpec is the spec part of the ScalingSchedule.
             properties:
+              scalingWindowDurationMinutes:
+                description: Fade the scheduled values in and out over this many minutes.
+                  If unset, the default per-cluster value will be used.
+                format: int64
+                type: integer
               schedules:
                 description: Schedules is the list of schedules for this ScalingSchedule
                   resource. All the schedules defined here will result on the value
@@ -96,6 +101,7 @@ spec:
                     value:
                       description: The metric value that will be returned for the
                         defined schedule.
+                      format: int64
                       type: integer
                   required:
                   - durationMinutes

go.mod

@@ -1,32 +1,32 @@
 module github.com/zalando-incubator/kube-metrics-adapter
 
 require (
-	github.com/NYTimes/gziphandler v1.0.1 // indirect
-	github.com/aws/aws-sdk-go v1.39.2
+	github.com/aws/aws-sdk-go v1.40.22
 	github.com/go-openapi/spec v0.20.3
 	github.com/influxdata/influxdb-client-go v0.2.0
 	github.com/influxdata/line-protocol v0.0.0-20201012155213-5f565037cbc9 // indirect
 	github.com/kubernetes-sigs/custom-metrics-apiserver v0.0.0-20201216091021-1b9fa998bbaa
 	github.com/mailru/easyjson v0.7.7 // indirect
-	github.com/prometheus/client_golang v1.10.0
-	github.com/prometheus/common v0.25.0
+	github.com/prometheus/client_golang v1.11.0
+	github.com/prometheus/common v0.26.0
 	github.com/sirupsen/logrus v1.8.1
 	github.com/spf13/cobra v1.1.3
 	github.com/spyzhov/ajson v0.4.2
 	github.com/stretchr/testify v1.7.0
+	github.com/szuecs/routegroup-client v0.18.3
 	github.com/zalando-incubator/cluster-lifecycle-manager v0.0.0-20180921141935-824b77fb1f84
-	golang.org/x/crypto v0.0.0-20201124201722-c8d3bf9c5392 // indirect
+	go.uber.org/zap v1.13.0 // indirect
 	golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d
 	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
-	k8s.io/api v0.20.5
-	k8s.io/apimachinery v0.20.5
-	k8s.io/apiserver v0.20.5
-	k8s.io/client-go v0.20.5
-	k8s.io/code-generator v0.20.5
-	k8s.io/component-base v0.20.5
+	k8s.io/api v0.21.5
+	k8s.io/apimachinery v0.21.5
+	k8s.io/apiserver v0.21.5
+	k8s.io/client-go v0.21.5
+	k8s.io/code-generator v0.21.5
+	k8s.io/component-base v0.21.5
 	k8s.io/klog v1.0.0
-	k8s.io/kube-openapi v0.0.0-20201113171705-d219536bb9fd
-	k8s.io/metrics v0.20.5
+	k8s.io/kube-openapi v0.0.0-20210305001622-591a79e4bda7
+	k8s.io/metrics v0.21.5
 	sigs.k8s.io/controller-tools v0.5.0
 )
 

pkg/apis/zalando.org/v1/types.go

@@ -1,6 +1,8 @@
 package v1
 
 import (
+	"time"
+
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
@@ -37,6 +39,10 @@ type ClusterScalingSchedule struct {
 // ScalingScheduleSpec is the spec part of the ScalingSchedule.
 // +k8s:deepcopy-gen=true
 type ScalingScheduleSpec struct {
+	// Fade the scheduled values in and out over this many minutes. If unset, the default per-cluster value will be used.
+	// +optional
+	ScalingWindowDurationMinutes *int64 `json:"scalingWindowDurationMinutes,omitempty"`
+
 	// Schedules is the list of schedules for this ScalingSchedule
 	// resource. All the schedules defined here will result on the value
 	// to the same metric. New metrics require a new ScalingSchedule
@@ -59,7 +65,11 @@ type Schedule struct {
 	// returned for the defined schedule.
 	DurationMinutes int `json:"durationMinutes"`
 	// The metric value that will be returned for the defined schedule.
-	Value int `json:"value"`
+	Value int64 `json:"value"`
+}
+
+func (in Schedule) Duration() time.Duration {
+	return time.Duration(in.DurationMinutes) * time.Minute
 }
 
 // Defines if the schedule is a OneTime schedule or
@@ -119,11 +129,11 @@ type ScalingScheduleList struct {
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
-// ScalingScheduleList is a list of cluster scoped scaling schedules.
+// ClusterScalingScheduleList is a list of cluster scoped scaling schedules.
 // +k8s:deepcopy-gen=true
 type ClusterScalingScheduleList struct {
 	metav1.TypeMeta `json:",inline"`
 	metav1.ListMeta `json:"metadata,omitempty"`
 
-	Items []ScalingSchedule `json:"items"`
+	Items []ClusterScalingSchedule `json:"items"`
 }

pkg/apis/zalando.org/v1/zz_generated.deepcopy.go

@@ -1,3 +1,4 @@
+//go:build !ignore_autogenerated
 // +build !ignore_autogenerated
 
 /*
@@ -58,7 +59,7 @@ func (in *ClusterScalingScheduleList) DeepCopyInto(out *ClusterScalingScheduleLi
 	in.ListMeta.DeepCopyInto(&out.ListMeta)
 	if in.Items != nil {
 		in, out := &in.Items, &out.Items
-		*out = make([]ScalingSchedule, len(*in))
+		*out = make([]ClusterScalingSchedule, len(*in))
 		for i := range *in {
 			(*in)[i].DeepCopyInto(&(*out)[i])
 		}
@@ -147,6 +148,11 @@ func (in *ScalingScheduleList) DeepCopyObject() runtime.Object {
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *ScalingScheduleSpec) DeepCopyInto(out *ScalingScheduleSpec) {
 	*out = *in
+	if in.ScalingWindowDurationMinutes != nil {
+		in, out := &in.ScalingWindowDurationMinutes, &out.ScalingWindowDurationMinutes
+		*out = new(int64)
+		**out = **in
+	}
 	if in.Schedules != nil {
 		in, out := &in.Schedules, &out.Schedules
 		*out = make([]Schedule, len(*in))

pkg/collector/collector.go

@@ -247,13 +247,19 @@ func ParseHPAMetrics(hpa *autoscalingv2.HorizontalPodAutoscaler) ([]*MetricConfi
 		}
 
 		if metric.Type == autoscalingv2.ExternalMetricSourceType &&
-			metric.External.Metric.Selector != nil &&
-			metric.External.Metric.Selector.MatchLabels != nil {
+			metric.External.Metric.Selector != nil {
 			for k, v := range metric.External.Metric.Selector.MatchLabels {
 				config.Config[k] = v
 			}
 		}
 
+		if metric.Type == autoscalingv2.ObjectMetricSourceType &&
+			metric.Object.Metric.Selector != nil {
+			for k, v := range metric.Object.Metric.Selector.MatchLabels {
+				config.Config[k] = v
+			}
+		}
+
 		annotationConfigs, present := parser.GetAnnotationConfig(typeName.Metric.Name, typeName.Type)
 		if present {
 			config.CollectorType = annotationConfigs.CollectorType

pkg/collector/httpmetrics/json_path.go

@@ -72,10 +72,25 @@ func (g *JSONPathMetricsGetter) GetMetric(metricsURL url.URL) (float64, error) {
 		return 0, err
 	}
 
-	if len(nodes) != 1 {
+	if len(nodes) == 0 {
 		return 0, fmt.Errorf("unexpected json: expected single numeric or array value")
 	}
 
+	if len(nodes) > 1 {
+		if g.aggregator == nil {
+			return 0, fmt.Errorf("no aggregator function has been specified")
+		}
+		values := make([]float64, 0, len(nodes))
+		for _, node := range nodes {
+			v, err := node.GetNumeric()
+			if err != nil {
+				return 0, fmt.Errorf("unexpected json: did not find numeric or array value '%s': %w", nodes, err)
+			}
+			values = append(values, v)
+		}
+		return g.aggregator(values...), nil
+	}
+
 	node := nodes[0]
 	if node.IsArray() {
 		if g.aggregator == nil {

pkg/collector/httpmetrics/json_path_test.go

@@ -51,6 +51,13 @@ func TestJSONPathMetricsGetter(t *testing.T) {
 			result:       5,
 			aggregator:   Average,
 		},
+		{
+			name:         "glob array query",
+			jsonResponse: []byte(`{"worker_status":[{"last_status":{"backlog":3}},{"last_status":{"backlog":7}}]}`),
+			jsonPath:     "$.worker_status.[*].last_status.backlog",
+			result:       5,
+			aggregator:   Average,
+		},
 		{
 			name:         "json path not resulting in array or number should lead to error",
 			jsonResponse: []byte(`{"metric.value":5}`),

pkg/collector/scaling_schedule_collector.go

@@ -3,6 +3,7 @@ package collector
 import (
 	"errors"
 	"fmt"
+	"math"
 	"time"
 
 	v1 "github.com/zalando-incubator/kube-metrics-adapter/pkg/apis/zalando.org/v1"
@@ -78,30 +79,38 @@ type Store interface {
 // ScalingScheduleCollectorPlugin is a collector plugin for initializing metrics
 // collectors for getting ScalingSchedule configured metrics.
 type ScalingScheduleCollectorPlugin struct {
-	store Store
-	now   Now
+	store                Store
+	now                  Now
+	defaultScalingWindow time.Duration
+	rampSteps            int
 }
 
 // ClusterScalingScheduleCollectorPlugin is a collector plugin for initializing metrics
 // collectors for getting ClusterScalingSchedule configured metrics.
 type ClusterScalingScheduleCollectorPlugin struct {
-	store Store
-	now   Now
+	store                Store
+	now                  Now
+	defaultScalingWindow time.Duration
+	rampSteps            int
 }
 
 // NewScalingScheduleCollectorPlugin initializes a new ScalingScheduleCollectorPlugin.
-func NewScalingScheduleCollectorPlugin(store Store, now Now) (*ScalingScheduleCollectorPlugin, error) {
+func NewScalingScheduleCollectorPlugin(store Store, now Now, defaultScalingWindow time.Duration, rampSteps int) (*ScalingScheduleCollectorPlugin, error) {
 	return &ScalingScheduleCollectorPlugin{
-		store: store,
-		now:   now,
+		store:                store,
+		now:                  now,
+		defaultScalingWindow: defaultScalingWindow,
+		rampSteps:            rampSteps,
 	}, nil
 }
 
 // NewClusterScalingScheduleCollectorPlugin initializes a new ClusterScalingScheduleCollectorPlugin.
-func NewClusterScalingScheduleCollectorPlugin(store Store, now Now) (*ClusterScalingScheduleCollectorPlugin, error) {
+func NewClusterScalingScheduleCollectorPlugin(store Store, now Now, defaultScalingWindow time.Duration, rampSteps int) (*ClusterScalingScheduleCollectorPlugin, error) {
 	return &ClusterScalingScheduleCollectorPlugin{
-		store: store,
-		now:   now,
+		store:                store,
+		now:                  now,
+		defaultScalingWindow: defaultScalingWindow,
+		rampSteps:            rampSteps,
 	}, nil
 }
 
@@ -109,14 +118,14 @@ func NewClusterScalingScheduleCollectorPlugin(store Store, now Now) (*ClusterSca
 // specified HPA. It's the only required method to implement the
 // collector.CollectorPlugin interface.
 func (c *ScalingScheduleCollectorPlugin) NewCollector(hpa *autoscalingv2.HorizontalPodAutoscaler, config *MetricConfig, interval time.Duration) (Collector, error) {
-	return NewScalingScheduleCollector(c.store, c.now, hpa, config, interval)
+	return NewScalingScheduleCollector(c.store, c.defaultScalingWindow, c.rampSteps, c.now, hpa, config, interval)
 }
 
 // NewCollector initializes a new cluster wide scaling schedule
 // collector from the specified HPA. It's the only required method to
 // implement the collector.CollectorPlugin interface.
 func (c *ClusterScalingScheduleCollectorPlugin) NewCollector(hpa *autoscalingv2.HorizontalPodAutoscaler, config *MetricConfig, interval time.Duration) (Collector, error) {
-	return NewClusterScalingScheduleCollector(c.store, c.now, hpa, config, interval)
+	return NewClusterScalingScheduleCollector(c.store, c.defaultScalingWindow, c.rampSteps, c.now, hpa, config, interval)
 }
 
 // ScalingScheduleCollector is a metrics collector for time based
@@ -135,41 +144,47 @@ type ClusterScalingScheduleCollector struct {
 // struct used by both ClusterScalingScheduleCollector and the
 // ScalingScheduleCollector.
 type scalingScheduleCollector struct {
-	store           Store
-	now             Now
-	metric          autoscalingv2.MetricIdentifier
-	objectReference custom_metrics.ObjectReference
-	hpa             *autoscalingv2.HorizontalPodAutoscaler
-	interval        time.Duration
-	config          MetricConfig
+	store                Store
+	now                  Now
+	metric               autoscalingv2.MetricIdentifier
+	objectReference      custom_metrics.ObjectReference
+	hpa                  *autoscalingv2.HorizontalPodAutoscaler
+	interval             time.Duration
+	config               MetricConfig
+	defaultScalingWindow time.Duration
+	rampSteps            int
 }
 
 // NewScalingScheduleCollector initializes a new ScalingScheduleCollector.
-func NewScalingScheduleCollector(store Store, now Now, hpa *autoscalingv2.HorizontalPodAutoscaler, config *MetricConfig, interval time.Duration) (*ScalingScheduleCollector, error) {
+func NewScalingScheduleCollector(store Store, defaultScalingWindow time.Duration, rampSteps int, now Now, hpa *autoscalingv2.HorizontalPodAutoscaler, config *MetricConfig, interval time.Duration) (*ScalingScheduleCollector, error) {
 	return &ScalingScheduleCollector{
 		scalingScheduleCollector{
-			store:           store,
-			now:             now,
-			objectReference: config.ObjectReference,
-			hpa:             hpa,
-			metric:          config.Metric,
-			interval:        interval,
-			config:          *config,
+			store:                store,
+			now:                  now,
+			objectReference:      config.ObjectReference,
+			hpa:                  hpa,
+			metric:               config.Metric,
+			interval:             interval,
+			config:               *config,
+			defaultScalingWindow: defaultScalingWindow,
+			rampSteps:            rampSteps,
 		},
 	}, nil
 }
 
 // NewClusterScalingScheduleCollector initializes a new ScalingScheduleCollector.
-func NewClusterScalingScheduleCollector(store Store, now Now, hpa *autoscalingv2.HorizontalPodAutoscaler, config *MetricConfig, interval time.Duration) (*ClusterScalingScheduleCollector, error) {
+func NewClusterScalingScheduleCollector(store Store, defaultScalingWindow time.Duration, rampSteps int, now Now, hpa *autoscalingv2.HorizontalPodAutoscaler, config *MetricConfig, interval time.Duration) (*ClusterScalingScheduleCollector, error) {
 	return &ClusterScalingScheduleCollector{
 		scalingScheduleCollector{
-			store:           store,
-			now:             now,
-			objectReference: config.ObjectReference,
-			hpa:             hpa,
-			metric:          config.Metric,
-			interval:        interval,
-			config:          *config,
+			store:                store,
+			now:                  now,
+			objectReference:      config.ObjectReference,
+			hpa:                  hpa,
+			metric:               config.Metric,
+			interval:             interval,
+			config:               *config,
+			defaultScalingWindow: defaultScalingWindow,
+			rampSteps:            rampSteps,
 		},
 	}, nil
 }
@@ -188,7 +203,7 @@ func (c *ScalingScheduleCollector) GetMetrics() ([]CollectedMetric, error) {
 	if !ok {
 		return nil, ErrNotScalingScheduleFound
 	}
-	return calculateMetrics(scalingSchedule.Spec.Schedules, c.now(), c.objectReference, c.metric)
+	return calculateMetrics(scalingSchedule.Spec, c.defaultScalingWindow, c.rampSteps, c.now(), c.objectReference, c.metric)
 }
 
 // GetMetrics is the main implementation for collector.Collector interface
@@ -221,7 +236,7 @@ func (c *ClusterScalingScheduleCollector) GetMetrics() ([]CollectedMetric, error
 		clusterScalingSchedule = v1.ClusterScalingSchedule(*scalingSchedule)
 	}
 
-	return calculateMetrics(clusterScalingSchedule.Spec.Schedules, c.now(), c.objectReference, c.metric)
+	return calculateMetrics(clusterScalingSchedule.Spec, c.defaultScalingWindow, c.rampSteps, c.now(), c.objectReference, c.metric)
 }
 
 // Interval returns the interval at which the collector should run.
@@ -234,9 +249,17 @@ func (c *ClusterScalingScheduleCollector) Interval() time.Duration {
 	return c.interval
 }
 
-func calculateMetrics(schedules []v1.Schedule, now time.Time, objectReference custom_metrics.ObjectReference, metric autoscalingv2.MetricIdentifier) ([]CollectedMetric, error) {
-	value := 0
-	for _, schedule := range schedules {
+func calculateMetrics(spec v1.ScalingScheduleSpec, defaultScalingWindow time.Duration, rampSteps int, now time.Time, objectReference custom_metrics.ObjectReference, metric autoscalingv2.MetricIdentifier) ([]CollectedMetric, error) {
+	scalingWindowDuration := defaultScalingWindow
+	if spec.ScalingWindowDurationMinutes != nil {
+		scalingWindowDuration = time.Duration(*spec.ScalingWindowDurationMinutes) * time.Minute
+	}
+	if scalingWindowDuration < 0 {
+		return nil, fmt.Errorf("scaling window duration cannot be negative")
+	}
+
+	value := int64(0)
+	for _, schedule := range spec.Schedules {
 		switch schedule.Type {
 		case v1.RepeatingSchedule:
 			location, err := time.LoadLocation(schedule.Period.Timezone)
@@ -269,9 +292,7 @@ func calculateMetrics(schedules []v1.Schedule, now time.Time, objectReference cu
 						parsedStartTime.Nanosecond(),
 						location,
 					)
-					if within(now, scheduledTime, schedule.DurationMinutes) && schedule.Value > value {
-						value = schedule.Value
-					}
+					value = maxInt64(value, valueForEntry(now, scheduledTime, schedule.Duration(), scalingWindowDuration, rampSteps, schedule.Value))
 					break
 				}
 			}
@@ -280,9 +301,8 @@ func calculateMetrics(schedules []v1.Schedule, now time.Time, objectReference cu
 			if err != nil {
 				return nil, ErrInvalidScheduleDate
 			}
-			if within(now, scheduledTime, schedule.DurationMinutes) && schedule.Value > value {
-				value = schedule.Value
-			}
+
+			value = maxInt64(value, valueForEntry(now, scheduledTime, schedule.Duration(), scalingWindowDuration, rampSteps, schedule.Value))
 		}
 	}
 
@@ -293,17 +313,56 @@ func calculateMetrics(schedules []v1.Schedule, now time.Time, objectReference cu
 			Custom: custom_metrics.MetricValue{
 				DescribedObject: objectReference,
 				Timestamp:       metav1.Time{Time: now},
-				Value:           *resource.NewMilliQuantity(int64(value*1000), resource.DecimalSI),
+				Value:           *resource.NewMilliQuantity(value*1000, resource.DecimalSI),
 				Metric:          custom_metrics.MetricIdentifier(metric),
 			},
 		},
 	}, nil
 }
 
-// within receive two time.Time and a number of minutes. It returns true
-// if the first given time, instant, is within the period of the second
-// given time (start) plus the given number of minutes.
-func within(instant, start time.Time, minutes int) bool {
-	return (instant.After(start) || instant.Equal(start)) &&
-		instant.Before(start.Add(time.Duration(minutes)*time.Minute))
+func valueForEntry(timestamp time.Time, startTime time.Time, entryDuration time.Duration, scalingWindowDuration time.Duration, rampSteps int, value int64) int64 {
+	scaleUpStart := startTime.Add(-scalingWindowDuration)
+	endTime := startTime.Add(entryDuration)
+	scaleUpEnd := endTime.Add(scalingWindowDuration)
+
+	if between(timestamp, startTime, endTime) {
+		return value
+	}
+	if between(timestamp, scaleUpStart, startTime) {
+		return scaledValue(timestamp, scaleUpStart, scalingWindowDuration, rampSteps, value)
+	}
+	if between(timestamp, endTime, scaleUpEnd) {
+		return scaledValue(scaleUpEnd, timestamp, scalingWindowDuration, rampSteps, value)
+	}
+	return 0
+}
+
+// The HPA has a rule to do not scale up or down if the change in the
+// metric is less than 10% (by default) of the current value. We will
+// use buckets of time using the floor of each as the returned metric.
+// Any config greater or equal to 10 buckets must guarantee changes
+// bigger than 10%.
+func scaledValue(timestamp time.Time, startTime time.Time, scalingWindowDuration time.Duration, rampSteps int, value int64) int64 {
+	if scalingWindowDuration == 0 {
+		return 0
+	}
+
+	steps := float64(rampSteps)
+
+	requiredPercentage := math.Abs(float64(timestamp.Sub(startTime))) / float64(scalingWindowDuration)
+	return int64(math.Floor(requiredPercentage*steps) * (float64(value) / steps))
+}
+
+func between(timestamp, start, end time.Time) bool {
+	if timestamp.Before(start) {
+		return false
+	}
+	return timestamp.Before(end)
+}
+
+func maxInt64(i1, i2 int64) int64 {
+	if i1 > i2 {
+		return i1
+	}
+	return i2
 }

pkg/collector/scaling_schedule_collector_test.go

@@ -12,7 +12,11 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
-const hHMMFormat = "15:04"
+const (
+	hHMMFormat                   = "15:04"
+	defaultScalingWindowDuration = 1 * time.Minute
+	defaultRampSteps             = 10
+)
 
 type schedule struct {
 	kind      string
@@ -21,7 +25,7 @@ type schedule struct {
 	days      []v1.ScheduleDay
 	timezone  string
 	duration  int
-	value     int
+	value     int64
 }
 
 func TestScalingScheduleCollector(t *testing.T) {
@@ -37,11 +41,15 @@ func TestScalingScheduleCollector(t *testing.T) {
 		return uTCNow
 	}
 
+	tenMinutes := int64(10)
+
 	for _, tc := range []struct {
-		msg           string
-		schedules     []schedule
-		expectedValue int
-		err           error
+		msg                          string
+		schedules                    []schedule
+		scalingWindowDurationMinutes *int64
+		expectedValue                int64
+		err                          error
+		rampSteps                    int
 	}{
 		{
 			msg: "Return the right value for one time config",
@@ -80,7 +88,70 @@ func TestScalingScheduleCollector(t *testing.T) {
 			expectedValue: 100,
 		},
 		{
-			msg: "Return the default value (0) for one time config - 30 seconds after",
+			msg: "Return the scaled value (60) for one time config - 20 seconds before starting",
+			schedules: []schedule{
+				{
+					date:     nowTime.Add(time.Second * 20).Format(time.RFC3339),
+					kind:     "OneTime",
+					duration: 45,
+					value:    100,
+				},
+			},
+			expectedValue: 60,
+		},
+		{
+			msg: "Return the scaled value (60) for one time config - 20 seconds after",
+			schedules: []schedule{
+				{
+					date:     nowTime.Add(-time.Minute * 45).Add(-time.Second * 20).Format(time.RFC3339),
+					kind:     "OneTime",
+					duration: 45,
+					value:    100,
+				},
+			},
+			expectedValue: 60,
+		},
+		{
+			msg: "10 steps (default) return 90% of the metric, even 1 second before",
+			schedules: []schedule{
+				{
+					date:     nowTime.Add(time.Second * 1).Format(time.RFC3339),
+					kind:     "OneTime",
+					duration: 45,
+					value:    100,
+				},
+			},
+			expectedValue: 90,
+		},
+		{
+			msg: "5 steps return 80% of the metric, even 1 second before",
+			schedules: []schedule{
+				{
+					date:     nowTime.Add(time.Second * 1).Format(time.RFC3339),
+					kind:     "OneTime",
+					duration: 45,
+					value:    100,
+				},
+			},
+			expectedValue: 80,
+			rampSteps:     5,
+		},
+		{
+			msg:                          "Return the scaled value (90) for one time config with a custom scaling window - 30 seconds before starting",
+			scalingWindowDurationMinutes: &tenMinutes,
+			schedules: []schedule{
+				{
+					date:     nowTime.Add(time.Second * 30).Format(time.RFC3339),
+					kind:     "OneTime",
+					duration: 45,
+					value:    100,
+				},
+			},
+			expectedValue: 90,
+		},
+		{
+			msg:                          "Return the scaled value (90) for one time config with a custom scaling window - 30 seconds after",
+			scalingWindowDurationMinutes: &tenMinutes,
 			schedules: []schedule{
 				{
 					date:     nowTime.Add(-time.Minute * 45).Add(-time.Second * 30).Format(time.RFC3339),
@@ -89,7 +160,7 @@ func TestScalingScheduleCollector(t *testing.T) {
 					value:    100,
 				},
 			},
-			expectedValue: 0,
+			expectedValue: 90,
 		},
 		{
 			msg: "Return the default value (0) for one time config not started yet (20 minutes before)",
@@ -427,17 +498,22 @@ func TestScalingScheduleCollector(t *testing.T) {
 			scalingScheduleName := "my_scaling_schedule"
 			namespace := "default"
 
+			rampSteps := tc.rampSteps
+			if rampSteps == 0 {
+				rampSteps = defaultRampSteps
+			}
+
 			schedules := getSchedules(tc.schedules)
-			store := newMockStore(scalingScheduleName, namespace, schedules)
-			plugin, err := NewScalingScheduleCollectorPlugin(store, now)
+			store := newMockStore(scalingScheduleName, namespace, tc.scalingWindowDurationMinutes, schedules)
+			plugin, err := NewScalingScheduleCollectorPlugin(store, now, defaultScalingWindowDuration, rampSteps)
 			require.NoError(t, err)
 
-			clusterStore := newClusterMockStore(scalingScheduleName, schedules)
-			clusterPlugin, err := NewClusterScalingScheduleCollectorPlugin(clusterStore, now)
+			clusterStore := newClusterMockStore(scalingScheduleName, tc.scalingWindowDurationMinutes, schedules)
+			clusterPlugin, err := NewClusterScalingScheduleCollectorPlugin(clusterStore, now, defaultScalingWindowDuration, rampSteps)
 			require.NoError(t, err)
 
-			clusterStoreFirstRun := newClusterMockStoreFirstRun(scalingScheduleName, schedules)
-			clusterPluginFirstRun, err := NewClusterScalingScheduleCollectorPlugin(clusterStoreFirstRun, now)
+			clusterStoreFirstRun := newClusterMockStoreFirstRun(scalingScheduleName, tc.scalingWindowDurationMinutes, schedules)
+			clusterPluginFirstRun, err := NewClusterScalingScheduleCollectorPlugin(clusterStoreFirstRun, now, defaultScalingWindowDuration, rampSteps)
 			require.NoError(t, err)
 
 			hpa := makeScalingScheduleHPA(namespace, scalingScheduleName)
@@ -505,14 +581,14 @@ func TestScalingScheduleObjectNotPresentReturnsError(t *testing.T) {
 		make(map[string]interface{}),
 		getByKeyFn,
 	}
-	plugin, err := NewScalingScheduleCollectorPlugin(store, time.Now)
+	plugin, err := NewScalingScheduleCollectorPlugin(store, time.Now, defaultScalingWindowDuration, defaultRampSteps)
 	require.NoError(t, err)
 
 	clusterStore := mockStore{
 		make(map[string]interface{}),
 		getByKeyFn,
 	}
-	clusterPlugin, err := NewClusterScalingScheduleCollectorPlugin(clusterStore, time.Now)
+	clusterPlugin, err := NewClusterScalingScheduleCollectorPlugin(clusterStore, time.Now, defaultScalingWindowDuration, defaultRampSteps)
 	require.NoError(t, err)
 
 	hpa := makeScalingScheduleHPA("namespace", "scalingScheduleName")
@@ -567,10 +643,10 @@ func TestReturnsErrorWhenStoreDoes(t *testing.T) {
 		},
 	}
 
-	plugin, err := NewScalingScheduleCollectorPlugin(store, time.Now)
+	plugin, err := NewScalingScheduleCollectorPlugin(store, time.Now, defaultScalingWindowDuration, defaultRampSteps)
 	require.NoError(t, err)
 
-	clusterPlugin, err := NewClusterScalingScheduleCollectorPlugin(store, time.Now)
+	clusterPlugin, err := NewClusterScalingScheduleCollectorPlugin(store, time.Now, defaultScalingWindowDuration, defaultRampSteps)
 	require.NoError(t, err)
 
 	hpa := makeScalingScheduleHPA("namespace", "scalingScheduleName")
@@ -615,7 +691,7 @@ func getByKeyFn(d map[string]interface{}, key string) (item interface{}, exists
 	return item, exists, nil
 }
 
-func newMockStore(name, namespace string, schedules []v1.Schedule) mockStore {
+func newMockStore(name, namespace string, scalingWindowDurationMinutes *int64, schedules []v1.Schedule) mockStore {
 	return mockStore{
 		map[string]interface{}{
 			fmt.Sprintf("%s/%s", namespace, name): &v1.ScalingSchedule{
@@ -623,7 +699,8 @@ func newMockStore(name, namespace string, schedules []v1.Schedule) mockStore {
 					Name: name,
 				},
 				Spec: v1.ScalingScheduleSpec{
-					Schedules: schedules,
+					ScalingWindowDurationMinutes: scalingWindowDurationMinutes,
+					Schedules:                    schedules,
 				},
 			},
 		},
@@ -631,7 +708,7 @@ func newMockStore(name, namespace string, schedules []v1.Schedule) mockStore {
 	}
 }
 
-func newClusterMockStore(name string, schedules []v1.Schedule) mockStore {
+func newClusterMockStore(name string, scalingWindowDurationMinutes *int64, schedules []v1.Schedule) mockStore {
 	return mockStore{
 		map[string]interface{}{
 			name: &v1.ClusterScalingSchedule{
@@ -639,7 +716,8 @@ func newClusterMockStore(name string, schedules []v1.Schedule) mockStore {
 					Name: name,
 				},
 				Spec: v1.ScalingScheduleSpec{
-					Schedules: schedules,
+					ScalingWindowDurationMinutes: scalingWindowDurationMinutes,
+					Schedules:                    schedules,
 				},
 			},
 		},
@@ -650,7 +728,7 @@ func newClusterMockStore(name string, schedules []v1.Schedule) mockStore {
 // The cache.Store returns the v1.ClusterScalingSchedule items as
 // v1.ScalingSchedule when it first lists it. When it's update it
 // asserts it correctly to the v1.ClusterScalingSchedule type.
-func newClusterMockStoreFirstRun(name string, schedules []v1.Schedule) mockStore {
+func newClusterMockStoreFirstRun(name string, scalingWindowDurationMinutes *int64, schedules []v1.Schedule) mockStore {
 	return mockStore{
 		map[string]interface{}{
 			name: &v1.ScalingSchedule{
@@ -658,7 +736,8 @@ func newClusterMockStoreFirstRun(name string, schedules []v1.Schedule) mockStore
 					Name: name,
 				},
 				Spec: v1.ScalingScheduleSpec{
-					Schedules: schedules,
+					ScalingWindowDurationMinutes: scalingWindowDurationMinutes,
+					Schedules:                    schedules,
 				},
 			},
 		},

pkg/collector/skipper_collector.go

@@ -10,6 +10,8 @@ import (
 	"strings"
 	"time"
 
+	rgv1 "github.com/szuecs/routegroup-client/apis/zalando.org/v1"
+	rginterface "github.com/szuecs/routegroup-client/client/clientset/versioned"
 	autoscalingv2 "k8s.io/api/autoscaling/v2beta2"
 	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -31,14 +33,16 @@ var (
 // collectors for getting skipper ingress metrics.
 type SkipperCollectorPlugin struct {
 	client             kubernetes.Interface
+	rgClient           rginterface.Interface
 	plugin             CollectorPlugin
 	backendAnnotations []string
 }
 
 // NewSkipperCollectorPlugin initializes a new SkipperCollectorPlugin.
-func NewSkipperCollectorPlugin(client kubernetes.Interface, prometheusPlugin *PrometheusCollectorPlugin, backendAnnotations []string) (*SkipperCollectorPlugin, error) {
+func NewSkipperCollectorPlugin(client kubernetes.Interface, rgClient rginterface.Interface, prometheusPlugin *PrometheusCollectorPlugin, backendAnnotations []string) (*SkipperCollectorPlugin, error) {
 	return &SkipperCollectorPlugin{
 		client:             client,
+		rgClient:           rgClient,
 		plugin:             prometheusPlugin,
 		backendAnnotations: backendAnnotations,
 	}, nil
@@ -47,14 +51,18 @@ func NewSkipperCollectorPlugin(client kubernetes.Interface, prometheusPlugin *Pr
 // NewCollector initializes a new skipper collector from the specified HPA.
 func (c *SkipperCollectorPlugin) NewCollector(hpa *autoscalingv2.HorizontalPodAutoscaler, config *MetricConfig, interval time.Duration) (Collector, error) {
 	if strings.HasPrefix(config.Metric.Name, rpsMetricName) {
-		backend := ""
-		if len(config.Metric.Name) > len(rpsMetricName) {
-			metricNameParts := strings.Split(config.Metric.Name, rpsMetricBackendSeparator)
-			if len(metricNameParts) == 2 {
-				backend = metricNameParts[1]
+		backend, ok := config.Config["backend"]
+		if !ok {
+			// TODO: remove the deprecated way of specifying
+			// optional backend at a later point in time.
+			if len(config.Metric.Name) > len(rpsMetricName) {
+				metricNameParts := strings.Split(config.Metric.Name, rpsMetricBackendSeparator)
+				if len(metricNameParts) == 2 {
+					backend = metricNameParts[1]
+				}
 			}
 		}
-		return NewSkipperCollector(c.client, c.plugin, hpa, config, interval, c.backendAnnotations, backend)
+		return NewSkipperCollector(c.client, c.rgClient, c.plugin, hpa, config, interval, c.backendAnnotations, backend)
 	}
 	return nil, fmt.Errorf("metric '%s' not supported", config.Metric.Name)
 }
@@ -63,6 +71,7 @@ func (c *SkipperCollectorPlugin) NewCollector(hpa *autoscalingv2.HorizontalPodAu
 // It depends on the prometheus collector for getting the metrics.
 type SkipperCollector struct {
 	client             kubernetes.Interface
+	rgClient           rginterface.Interface
 	metric             autoscalingv2.MetricIdentifier
 	objectReference    custom_metrics.ObjectReference
 	hpa                *autoscalingv2.HorizontalPodAutoscaler
@@ -74,9 +83,10 @@ type SkipperCollector struct {
 }
 
 // NewSkipperCollector initializes a new SkipperCollector.
-func NewSkipperCollector(client kubernetes.Interface, plugin CollectorPlugin, hpa *autoscalingv2.HorizontalPodAutoscaler, config *MetricConfig, interval time.Duration, backendAnnotations []string, backend string) (*SkipperCollector, error) {
+func NewSkipperCollector(client kubernetes.Interface, rgClient rginterface.Interface, plugin CollectorPlugin, hpa *autoscalingv2.HorizontalPodAutoscaler, config *MetricConfig, interval time.Duration, backendAnnotations []string, backend string) (*SkipperCollector, error) {
 	return &SkipperCollector{
 		client:             client,
+		rgClient:           rgClient,
 		objectReference:    config.ObjectReference,
 		hpa:                hpa,
 		metric:             config.Metric,
@@ -100,7 +110,7 @@ func getAnnotationWeight(backendWeights string, backend string) (float64, error)
 	return 0, nil
 }
 
-func getWeights(ingressAnnotations map[string]string, backendAnnotations []string, backend string) (float64, error) {
+func getIngressWeight(ingressAnnotations map[string]string, backendAnnotations []string, backend string) (float64, error) {
 	maxWeight := 0.0
 	annotationsPresent := false
 
@@ -128,26 +138,65 @@ func getWeights(ingressAnnotations map[string]string, backendAnnotations []strin
 	return 0.0, errBackendNameMissing
 }
 
-// getCollector returns a collector for getting the metrics.
-func (c *SkipperCollector) getCollector() (Collector, error) {
-	ingress, err := c.client.NetworkingV1beta1().Ingresses(c.objectReference.Namespace).Get(context.TODO(), c.objectReference.Name, metav1.GetOptions{})
-	if err != nil {
-		return nil, err
+func getRouteGroupWeight(backends []rgv1.RouteGroupBackendReference, backendName string) (float64, error) {
+	if len(backends) <= 1 {
+		return 1.0, nil
 	}
 
-	backendWeight, err := getWeights(ingress.Annotations, c.backendAnnotations, c.backend)
-	if err != nil {
-		return nil, err
+	if backendName == "" {
+		return 0.0, errBackendNameMissing
 	}
+
+	for _, backend := range backends {
+		if backend.BackendName == backendName {
+			return float64(backend.Weight) / 100.0, nil
+		}
+	}
+
+	return 0.0, nil
+}
+
+// getCollector returns a collector for getting the metrics.
+func (c *SkipperCollector) getCollector(ctx context.Context) (Collector, error) {
+	var escapedHostnames []string
+	var backendWeight float64
+	switch c.objectReference.Kind {
+	case "Ingress":
+		ingress, err := c.client.NetworkingV1beta1().Ingresses(c.objectReference.Namespace).Get(ctx, c.objectReference.Name, metav1.GetOptions{})
+		if err != nil {
+			return nil, err
+		}
+
+		backendWeight, err = getIngressWeight(ingress.Annotations, c.backendAnnotations, c.backend)
+		if err != nil {
+			return nil, err
+		}
+
+		for _, rule := range ingress.Spec.Rules {
+			escapedHostnames = append(escapedHostnames, regexp.QuoteMeta(strings.Replace(rule.Host, ".", "_", -1)))
+		}
+	case "RouteGroup":
+		routegroup, err := c.rgClient.ZalandoV1().RouteGroups(c.objectReference.Namespace).Get(ctx, c.objectReference.Name, metav1.GetOptions{})
+		if err != nil {
+			return nil, err
+		}
+
+		backendWeight, err = getRouteGroupWeight(routegroup.Spec.DefaultBackends, c.backend)
+		if err != nil {
+			return nil, err
+		}
+
+		for _, host := range routegroup.Spec.Hosts {
+			escapedHostnames = append(escapedHostnames, regexp.QuoteMeta(strings.Replace(host, ".", "_", -1)))
+		}
+	default:
+		return nil, fmt.Errorf("unknown skipper resource kind %s for resource %s/%s", c.objectReference.Kind, c.objectReference.Namespace, c.objectReference.Name)
+	}
+
 	config := c.config
 
-	var escapedHostnames []string
-	for _, rule := range ingress.Spec.Rules {
-		escapedHostnames = append(escapedHostnames, regexp.QuoteMeta(strings.Replace(rule.Host, ".", "_", -1)))
-	}
-
 	if len(escapedHostnames) == 0 {
-		return nil, fmt.Errorf("no hosts defined on ingress %s/%s, unable to create collector", c.objectReference.Namespace, c.objectReference.Name)
+		return nil, fmt.Errorf("no hosts defined on %s %s/%s, unable to create collector", c.objectReference.Kind, c.objectReference.Namespace, c.objectReference.Name)
 	}
 
 	config.Config = map[string]string{
@@ -165,7 +214,7 @@ func (c *SkipperCollector) getCollector() (Collector, error) {
 
 // GetMetrics gets skipper metrics from prometheus.
 func (c *SkipperCollector) GetMetrics() ([]CollectedMetric, error) {
-	collector, err := c.getCollector()
+	collector, err := c.getCollector(context.TODO())
 	if err != nil {
 		return nil, err
 	}

pkg/provider/metric_store.go

@@ -82,6 +82,16 @@ func (s *MetricStore) insertCustomMetric(value custom_metrics.MetricValue) {
 			Resource: "ingresses",
 			Group:    group,
 		}
+	case "RouteGroup":
+		group := "zalando.org"
+		gv, err := schema.ParseGroupVersion(value.DescribedObject.APIVersion)
+		if err == nil {
+			group = gv.Group
+		}
+		groupResource = schema.GroupResource{
+			Resource: "routegroups",
+			Group:    group,
+		}
 	case "ScalingSchedule":
 		group := "zalando.org"
 		gv, err := schema.ParseGroupVersion(value.DescribedObject.APIVersion)

pkg/server/start.go

@@ -30,6 +30,7 @@ import (
 	"github.com/kubernetes-sigs/custom-metrics-apiserver/pkg/cmd/server"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/spf13/cobra"
+	rg "github.com/szuecs/routegroup-client/client/clientset/versioned"
 	"github.com/zalando-incubator/cluster-lifecycle-manager/pkg/credentials-loader/platformiam"
 	generatedopenapi "github.com/zalando-incubator/kube-metrics-adapter/pkg/api/generated/openapi"
 	v1 "github.com/zalando-incubator/kube-metrics-adapter/pkg/apis/zalando.org/v1"
@@ -113,6 +114,8 @@ func NewCommandStartAdapterServer(stopCh <-chan struct{}) *cobra.Command {
 		"path to the credentials dir where tokens are stored")
 	flags.BoolVar(&o.SkipperIngressMetrics, "skipper-ingress-metrics", o.SkipperIngressMetrics, ""+
 		"whether to enable skipper ingress metrics")
+	flags.BoolVar(&o.SkipperRouteGroupMetrics, "skipper-routegroup-metrics", o.SkipperRouteGroupMetrics, ""+
+		"whether to enable skipper routegroup metrics")
 	flags.StringArrayVar(&o.SkipperBackendWeightAnnotation, "skipper-backends-annotation", o.SkipperBackendWeightAnnotation, ""+
 		"the annotation to get backend weights so that the returned metric can be weighted")
 	flags.BoolVar(&o.AWSExternalMetrics, "aws-external-metrics", o.AWSExternalMetrics, ""+
@@ -125,6 +128,8 @@ func NewCommandStartAdapterServer(stopCh <-chan struct{}) *cobra.Command {
 	flags.DurationVar(&o.GCInterval, "garbage-collector-interval", 10*time.Minute, "Interval to clean up metrics that are stored in in-memory cache.")
 	flags.BoolVar(&o.ScalingScheduleMetrics, "scaling-schedule", o.ScalingScheduleMetrics, ""+
 		"whether to enable time-based ScalingSchedule metrics")
+	flags.DurationVar(&o.DefaultScheduledScalingWindow, "scaling-schedule-default-scaling-window", 10*time.Minute, "Default rampup and rampdown window duration for ScalingSchedules")
+	flags.IntVar(&o.RampSteps, "scaling-schedule-ramp-steps", 10, "Number of steps used to rampup and rampdown ScalingSchedules. It's used to guarantee won't avoid reaching the max scaling due to the 10% minimum change rule.")
 	return cmd
 }
 
@@ -170,6 +175,11 @@ func (o AdapterServerOptions) RunCustomMetricsAdapterServer(stopCh <-chan struct
 		return fmt.Errorf("failed to initialize new client: %v", err)
 	}
 
+	rgClient, err := rg.NewForConfig(clientConfig)
+	if err != nil {
+		return fmt.Errorf("failed to initialize RouteGroup client: %v", err)
+	}
+
 	collectorFactory := collector.NewCollectorFactory()
 
 	if o.PrometheusServer != "" {
@@ -186,15 +196,24 @@ func (o AdapterServerOptions) RunCustomMetricsAdapterServer(stopCh <-chan struct
 		collectorFactory.RegisterExternalCollector([]string{collector.PrometheusMetricType, collector.PrometheusMetricNameLegacy}, promPlugin)
 
 		// skipper collector can only be enabled if prometheus is.
-		if o.SkipperIngressMetrics {
-			skipperPlugin, err := collector.NewSkipperCollectorPlugin(client, promPlugin, o.SkipperBackendWeightAnnotation)
+		if o.SkipperIngressMetrics || o.SkipperRouteGroupMetrics {
+			skipperPlugin, err := collector.NewSkipperCollectorPlugin(client, rgClient, promPlugin, o.SkipperBackendWeightAnnotation)
 			if err != nil {
 				return fmt.Errorf("failed to initialize skipper collector plugin: %v", err)
 			}
 
-			err = collectorFactory.RegisterObjectCollector("Ingress", "", skipperPlugin)
-			if err != nil {
-				return fmt.Errorf("failed to register skipper collector plugin: %v", err)
+			if o.SkipperIngressMetrics {
+				err = collectorFactory.RegisterObjectCollector("Ingress", "", skipperPlugin)
+				if err != nil {
+					return fmt.Errorf("failed to register skipper Ingress collector plugin: %v", err)
+				}
+			}
+
+			if o.SkipperRouteGroupMetrics {
+				err = collectorFactory.RegisterObjectCollector("RouteGroup", "", skipperPlugin)
+				if err != nil {
+					return fmt.Errorf("failed to register skipper RouteGroup collector plugin: %v", err)
+				}
 			}
 		}
 	}
@@ -276,7 +295,7 @@ func (o AdapterServerOptions) RunCustomMetricsAdapterServer(stopCh <-chan struct
 		)
 		go reflector.Run(ctx.Done())
 
-		clusterPlugin, err := collector.NewClusterScalingScheduleCollectorPlugin(clusterScalingSchedulesStore, time.Now)
+		clusterPlugin, err := collector.NewClusterScalingScheduleCollectorPlugin(clusterScalingSchedulesStore, time.Now, o.DefaultScheduledScalingWindow, o.RampSteps)
 		if err != nil {
 			return fmt.Errorf("unable to create ClusterScalingScheduleCollector plugin: %v", err)
 		}
@@ -285,7 +304,7 @@ func (o AdapterServerOptions) RunCustomMetricsAdapterServer(stopCh <-chan struct
 			return fmt.Errorf("failed to register ClusterScalingSchedule object collector plugin: %v", err)
 		}
 
-		plugin, err := collector.NewScalingScheduleCollectorPlugin(scalingSchedulesStore, time.Now)
+		plugin, err := collector.NewScalingScheduleCollectorPlugin(scalingSchedulesStore, time.Now, o.DefaultScheduledScalingWindow, o.RampSteps)
 		if err != nil {
 			return fmt.Errorf("unable to create ScalingScheduleCollector plugin: %v", err)
 		}
@@ -390,6 +409,9 @@ type AdapterServerOptions struct {
 	// SkipperIngressMetrics switches on support for skipper ingress based
 	// metric collection.
 	SkipperIngressMetrics bool
+	// SkipperRouteGroupMetrics switches on support for skipper routegroup
+	// based metric collection.
+	SkipperRouteGroupMetrics bool
 	// AWSExternalMetrics switches on support for getting external metrics
 	// from AWS.
 	AWSExternalMetrics bool
@@ -408,4 +430,8 @@ type AdapterServerOptions struct {
 	GCInterval time.Duration
 	// Time-based scaling based on the CRDs ScheduleScaling and ClusterScheduleScaling.
 	ScalingScheduleMetrics bool
+	// Default ramp-up/ramp-down window duration for scheduled metrics
+	DefaultScheduledScalingWindow time.Duration
+	// Number of steps utilized during the rampup and rampdown for scheduled metrics
+	RampSteps int
 }