Revert "feat: Add option to enabled warmup when leader election is used (kubernetes-sigs#2740)"

This reverts commit 3c00d41.

Author: nathangeology

pkg/operator/operator.go

@@ -48,7 +48,6 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/cache"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/client/apiutil"
-	ctrlconfig "sigs.k8s.io/controller-runtime/pkg/config"
 	"sigs.k8s.io/controller-runtime/pkg/healthz"
 	"sigs.k8s.io/controller-runtime/pkg/log"
 	"sigs.k8s.io/controller-runtime/pkg/manager"
@@ -180,12 +179,6 @@ func NewOperator(o ...option.Function[Options]) (context.Context, *Operator) {
 				},
 			},
 		},
-		Controller: ctrlconfig.Controller{
-			// EnableWarmup allows controllers to start their sources (watches/informers) before leader election
-			// is won. This pre-populates caches and improves leader failover time. Only effective when leader
-			// election is enabled, so we only set it when both conditions are true.
-			EnableWarmup: lo.ToPtr(!options.FromContext(ctx).DisableLeaderElection && !options.FromContext(ctx).DisableControllerWarmup),
-		},
 	}
 	if options.FromContext(ctx).EnableProfiling {
 		// TODO @joinnis: Investigate the mgrOpts.PprofBindAddress that would allow native support for pprof

pkg/operator/options/options.go

@@ -71,7 +71,6 @@ type Options struct {
 	KubeClientQPS                    int
 	KubeClientBurst                  int
 	EnableProfiling                  bool
-	DisableControllerWarmup          bool
 	DisableLeaderElection            bool
 	DisableClusterStateObservability bool
 	LeaderElectionName               string
@@ -115,7 +114,6 @@ func (o *Options) AddFlags(fs *FlagSet) {
 	fs.IntVar(&o.KubeClientQPS, "kube-client-qps", env.WithDefaultInt("KUBE_CLIENT_QPS", 200), "The smoothed rate of qps to kube-apiserver")
 	fs.IntVar(&o.KubeClientBurst, "kube-client-burst", env.WithDefaultInt("KUBE_CLIENT_BURST", 300), "The maximum allowed burst of queries to the kube-apiserver")
 	fs.BoolVarWithEnv(&o.EnableProfiling, "enable-profiling", "ENABLE_PROFILING", false, "Enable the profiling on the metric endpoint")
-	fs.BoolVarWithEnv(&o.DisableControllerWarmup, "disable-controller-warmup", "DISABLE_CONTROLLER_WARMUP", true, "Disable controller warmup which starts controller sources before leader election is won. Controller warmup pre-populates caches and improves leader failover time.")
 	fs.BoolVarWithEnv(&o.DisableLeaderElection, "disable-leader-election", "DISABLE_LEADER_ELECTION", false, "Disable the leader election client before executing the main loop. Disable when running replicated components for high availability is not desired.")
 	fs.BoolVarWithEnv(&o.DisableClusterStateObservability, "disable-cluster-state-observability", "DISABLE_CLUSTER_STATE_OBSERVABILITY", false, "Disable cluster state metrics and events")
 	fs.StringVar(&o.LeaderElectionName, "leader-election-name", env.WithDefaultString("LEADER_ELECTION_NAME", "karpenter-leader-election"), "Leader election name to create and monitor the lease if running outside the cluster")

pkg/operator/options/suite_test.go

@@ -52,7 +52,6 @@ var _ = Describe("Options", func() {
 		"KUBE_CLIENT_QPS",
 		"KUBE_CLIENT_BURST",
 		"ENABLE_PROFILING",
-		"DISABLE_CONTROLLER_WARMUP",
 		"DISABLE_LEADER_ELECTION",
 		"DISABLE_CLUSTER_STATE_OBSERVABILITY",
 		"LEADER_ELECTION_NAMESPACE",
@@ -107,7 +106,6 @@ var _ = Describe("Options", func() {
 				KubeClientQPS:                    lo.ToPtr(200),
 				KubeClientBurst:                  lo.ToPtr(300),
 				EnableProfiling:                  lo.ToPtr(false),
-				DisableControllerWarmup:          lo.ToPtr(true),
 				DisableLeaderElection:            lo.ToPtr(false),
 				DisableClusterStateObservability: lo.ToPtr(false),
 				LeaderElectionName:               lo.ToPtr("karpenter-leader-election"),
@@ -142,7 +140,6 @@ var _ = Describe("Options", func() {
 				"--kube-client-qps", "0",
 				"--kube-client-burst", "0",
 				"--enable-profiling",
-				"--disable-controller-warmup=false",
 				"--disable-leader-election=true",
 				"--disable-cluster-state-observability=true",
 				"--leader-election-name=karpenter-controller",
@@ -165,7 +162,6 @@ var _ = Describe("Options", func() {
 				KubeClientQPS:                    lo.ToPtr(0),
 				KubeClientBurst:                  lo.ToPtr(0),
 				EnableProfiling:                  lo.ToPtr(true),
-				DisableControllerWarmup:          lo.ToPtr(false),
 				DisableLeaderElection:            lo.ToPtr(true),
 				DisableClusterStateObservability: lo.ToPtr(true),
 				LeaderElectionName:               lo.ToPtr("karpenter-controller"),
@@ -196,7 +192,6 @@ var _ = Describe("Options", func() {
 			os.Setenv("KUBE_CLIENT_QPS", "0")
 			os.Setenv("KUBE_CLIENT_BURST", "0")
 			os.Setenv("ENABLE_PROFILING", "true")
-			os.Setenv("DISABLE_CONTROLLER_WARMUP", "false")
 			os.Setenv("DISABLE_LEADER_ELECTION", "true")
 			os.Setenv("DISABLE_CLUSTER_STATE_OBSERVABILITY", "true")
 			os.Setenv("LEADER_ELECTION_NAME", "karpenter-controller")
@@ -223,7 +218,6 @@ var _ = Describe("Options", func() {
 				KubeClientQPS:                    lo.ToPtr(0),
 				KubeClientBurst:                  lo.ToPtr(0),
 				EnableProfiling:                  lo.ToPtr(true),
-				DisableControllerWarmup:          lo.ToPtr(false),
 				DisableLeaderElection:            lo.ToPtr(true),
 				DisableClusterStateObservability: lo.ToPtr(true),
 				LeaderElectionName:               lo.ToPtr("karpenter-controller"),
@@ -253,7 +247,6 @@ var _ = Describe("Options", func() {
 			os.Setenv("KUBE_CLIENT_QPS", "0")
 			os.Setenv("KUBE_CLIENT_BURST", "0")
 			os.Setenv("ENABLE_PROFILING", "true")
-			os.Setenv("DISABLE_CONTROLLER_WARMUP", "false")
 			os.Setenv("DISABLE_LEADER_ELECTION", "true")
 			os.Setenv("DISABLE_CLUSTER_STATE_OBSERVABILITY", "true")
 			os.Setenv("MEMORY_LIMIT", "0")
@@ -283,7 +276,6 @@ var _ = Describe("Options", func() {
 				KubeClientQPS:                    lo.ToPtr(0),
 				KubeClientBurst:                  lo.ToPtr(0),
 				EnableProfiling:                  lo.ToPtr(true),
-				DisableControllerWarmup:          lo.ToPtr(false),
 				DisableLeaderElection:            lo.ToPtr(true),
 				DisableClusterStateObservability: lo.ToPtr(true),
 				LeaderElectionName:               lo.ToPtr("karpenter-leader-election"),
@@ -389,7 +381,6 @@ func expectOptionsMatch(optsA, optsB *options.Options) {
 	Expect(optsA.KubeClientQPS).To(Equal(optsB.KubeClientQPS))
 	Expect(optsA.KubeClientBurst).To(Equal(optsB.KubeClientBurst))
 	Expect(optsA.EnableProfiling).To(Equal(optsB.EnableProfiling))
-	Expect(optsA.DisableControllerWarmup).To(Equal(optsB.DisableControllerWarmup))
 	Expect(optsA.DisableLeaderElection).To(Equal(optsB.DisableLeaderElection))
 	Expect(optsA.DisableClusterStateObservability).To(Equal(optsB.DisableClusterStateObservability))
 	Expect(optsA.MemoryLimit).To(Equal(optsB.MemoryLimit))

pkg/test/options.go

@@ -34,7 +34,6 @@ type OptionsFields struct {
 	KubeClientQPS                    *int
 	KubeClientBurst                  *int
 	EnableProfiling                  *bool
-	DisableControllerWarmup          *bool
 	DisableLeaderElection            *bool
 	DisableClusterStateObservability *bool
 	LeaderElectionName               *string
@@ -75,7 +74,6 @@ func Options(overrides ...OptionsFields) *options.Options {
 		KubeClientQPS:                    lo.FromPtrOr(opts.KubeClientQPS, 200),
 		KubeClientBurst:                  lo.FromPtrOr(opts.KubeClientBurst, 300),
 		EnableProfiling:                  lo.FromPtrOr(opts.EnableProfiling, false),
-		DisableControllerWarmup:          lo.FromPtrOr(opts.DisableControllerWarmup, true),
 		DisableLeaderElection:            lo.FromPtrOr(opts.DisableLeaderElection, false),
 		DisableClusterStateObservability: lo.FromPtrOr(opts.DisableClusterStateObservability, false),
 		MemoryLimit:                      lo.FromPtrOr(opts.MemoryLimit, -1),