autoscaler.go

/*
Copyright 2016 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package core

import (
	"context"
	"strings"
	"time"

	cqv1alpha1 "k8s.io/autoscaler/cluster-autoscaler/apis/capacityquota/autoscaling.x-k8s.io/v1alpha1"
	cloudBuilder "k8s.io/autoscaler/cluster-autoscaler/cloudprovider/builder"
	ca_context "k8s.io/autoscaler/cluster-autoscaler/context"
	coreoptions "k8s.io/autoscaler/cluster-autoscaler/core/options"
	"k8s.io/autoscaler/cluster-autoscaler/core/scaledown/pdb"
	"k8s.io/autoscaler/cluster-autoscaler/core/utils"
	"k8s.io/autoscaler/cluster-autoscaler/estimator"
	"k8s.io/autoscaler/cluster-autoscaler/expander/factory"
	"k8s.io/autoscaler/cluster-autoscaler/observers/loopstart"
	ca_processors "k8s.io/autoscaler/cluster-autoscaler/processors"
	"k8s.io/autoscaler/cluster-autoscaler/resourcequotas"
	"k8s.io/autoscaler/cluster-autoscaler/resourcequotas/capacityquota"
	"k8s.io/autoscaler/cluster-autoscaler/simulator/clustersnapshot/predicate"
	"k8s.io/autoscaler/cluster-autoscaler/simulator/clustersnapshot/store"
	csinodeprovider "k8s.io/autoscaler/cluster-autoscaler/simulator/csi/provider"
	"k8s.io/autoscaler/cluster-autoscaler/simulator/drainability/rules"
	draprovider "k8s.io/autoscaler/cluster-autoscaler/simulator/dynamicresources/provider"
	"k8s.io/autoscaler/cluster-autoscaler/simulator/framework"
	"k8s.io/autoscaler/cluster-autoscaler/utils/backoff"
	"k8s.io/autoscaler/cluster-autoscaler/utils/errors"
	"k8s.io/client-go/informers"
)

// Autoscaler is the main component of CA which scales up/down node groups according to its configuration
// The configuration can be injected at the creation of an autoscaler
type Autoscaler interface {
	// Start starts components running in background.
	Start() error
	// RunOnce represents an iteration in the control-loop of CA
	RunOnce(currentTime time.Time) errors.AutoscalerError
	// ExitCleanUp is a clean-up performed just before process termination.
	ExitCleanUp()
	// LastScaleUpTime is a time of the last scale up
	LastScaleUpTime() time.Time
	// LastScaleDownDeleteTime is a time of the last scale down
	LastScaleDownDeleteTime() time.Time
}

// NewAutoscaler creates an autoscaler of an appropriate type according to the parameters
func NewAutoscaler(ctx context.Context, opts coreoptions.AutoscalerOptions, informerFactory informers.SharedInformerFactory) (Autoscaler, errors.AutoscalerError) {
	err := initializeDefaultOptions(ctx, &opts, informerFactory)
	if err != nil {
		return nil, errors.ToAutoscalerError(errors.InternalError, err)
	}
	return NewStaticAutoscaler(
		opts.AutoscalingOptions,
		opts.FrameworkHandle,
		opts.ClusterSnapshot,
		opts.AutoscalingKubeClients,
		opts.Processors,
		opts.LoopStartNotifier,
		opts.CloudProvider,
		opts.ExpanderStrategy,
		opts.EstimatorBuilder,
		opts.Backoff,
		opts.DebuggingSnapshotter,
		opts.RemainingPdbTracker,
		opts.ScaleUpOrchestrator,
		opts.DeleteOptions,
		opts.DrainabilityRules,
		opts.DraProvider,
		opts.QuotasTrackerOptions,
		opts.CSIProvider,
		opts.CapacityBufferPodsRegistry,
	), nil
}

// Initialize default options if not provided.
func initializeDefaultOptions(ctx context.Context, opts *coreoptions.AutoscalerOptions, informerFactory informers.SharedInformerFactory) error {
	if opts.Processors == nil {
		opts.Processors = ca_processors.DefaultProcessors(opts.AutoscalingOptions)
	}
	if opts.LoopStartNotifier == nil {
		opts.LoopStartNotifier = loopstart.NewObserversList(nil)
	}
	if opts.AutoscalingKubeClients == nil {
		opts.AutoscalingKubeClients = ca_context.NewAutoscalingKubeClients(ctx, opts.AutoscalingOptions, opts.KubeClient, opts.InformerFactory)
	}
	if opts.FrameworkHandle == nil {
		fwHandle, err := framework.NewHandle(ctx, opts.InformerFactory, opts.SchedulerConfig, opts.DynamicResourceAllocationEnabled, opts.CSINodeAwareSchedulingEnabled, opts.FastPredicatesEnabled)
		if err != nil {
			return err
		}
		opts.FrameworkHandle = fwHandle
	}
	if opts.ClusterSnapshot == nil {
		opts.ClusterSnapshot = predicate.NewPredicateSnapshot(store.NewBasicSnapshotStore(opts.FastPredicatesEnabled), opts.FrameworkHandle, opts.DynamicResourceAllocationEnabled, opts.PredicateParallelism, opts.CSINodeAwareSchedulingEnabled, opts.FastPredicatesEnabled)
	}
	if opts.RemainingPdbTracker == nil {
		opts.RemainingPdbTracker = pdb.NewBasicRemainingPdbTracker()
	}
	if opts.EstimatorBuilder == nil {
		thresholds := []estimator.Threshold{
			estimator.NewStaticThreshold(opts.MaxNodesPerScaleUp, opts.MaxNodeGroupBinpackingDuration),
			estimator.NewSngCapacityThreshold(),
			estimator.NewClusterCapacityThreshold(),
		}
		estimatorBuilder, err := estimator.NewEstimatorBuilder(
			opts.EstimatorName,
			estimator.NewThresholdBasedEstimationLimiter(thresholds),
			estimator.NewDecreasingPodOrderer(),
			/* EstimationAnalyserFunc */ nil,
			opts.FastpathBinpackingEnabled,
		)
		if err != nil {
			return err
		}
		opts.EstimatorBuilder = estimatorBuilder
	}
	if opts.Backoff == nil {
		opts.Backoff =
			backoff.NewIdBasedExponentialBackoff(opts.InitialNodeGroupBackoffDuration, opts.MaxNodeGroupBackoffDuration, opts.NodeGroupBackoffResetTimeout)
	}
	if opts.DrainabilityRules == nil {
		opts.DrainabilityRules = rules.Default(opts.DeleteOptions)
	}
	if opts.DraProvider == nil && opts.DynamicResourceAllocationEnabled {
		opts.DraProvider = draprovider.NewProviderFromInformers(informerFactory)
	}
	if opts.CloudProvider == nil {
		opts.CloudProvider = cloudBuilder.NewCloudProvider(opts, informerFactory)
	}
	if opts.ExpanderStrategy == nil {
		expanderFactory := factory.NewFactory()
		expanderFactory.RegisterDefaultExpanders(opts.CloudProvider, opts.AutoscalingKubeClients, opts.KubeClient, opts.ConfigNamespace, opts.GRPCExpanderCert, opts.GRPCExpanderURL)
		expanderStrategy, err := expanderFactory.Build(strings.Split(opts.ExpanderNames, ","))
		if err != nil {
			return err
		}
		opts.ExpanderStrategy = expanderStrategy
	}
	if opts.QuotasTrackerOptions.QuotaProvider == nil {
		providers := []resourcequotas.Provider{resourcequotas.NewCloudQuotasProvider(opts.CloudProvider)}

		if opts.CapacityQuotasEnabled {
			// register informer here to disable lazy initialization
			if _, err := opts.KubeCache.GetInformer(context.TODO(), &cqv1alpha1.CapacityQuota{}); err != nil {
				return err
			}
			providers = append(providers, capacityquota.NewCapacityQuotasProvider(opts.KubeClientNew))
		}
		opts.QuotasTrackerOptions.QuotaProvider = resourcequotas.NewCombinedQuotasProvider(providers)
	}
	if opts.QuotasTrackerOptions.CustomResourcesProcessor == nil {
		opts.QuotasTrackerOptions.CustomResourcesProcessor = opts.Processors.CustomResourcesProcessor
	}
	if opts.QuotasTrackerOptions.NodeFilter == nil {
		virtualKubeletNodeFilter := utils.VirtualKubeletNodeFilter{}
		opts.QuotasTrackerOptions.NodeFilter = resourcequotas.NewCombinedNodeFilter([]resourcequotas.NodeFilter{virtualKubeletNodeFilter})
	}

	if opts.CSINodeAwareSchedulingEnabled {
		csiProvider := csinodeprovider.NewCSINodeProviderFromInformers(informerFactory)
		opts.CSIProvider = csiProvider
	}
	return nil
}