Merge pull request k0sproject#5490 from twz123/single-controller

Disable leader election in single-controller clusters
PhoenixRedflash · Feb 3, 2025 · ea288c3 · ea288c3
2 parents f68a783 + adf0968
commit ea288c3
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Showing 4 changed files with 24 additions and 21 deletions.
diff --git a/cmd/controller/controller.go b/cmd/controller/controller.go
@@ -242,6 +242,9 @@ func (c *command) start(ctx context.Context) error {
 	logrus.Infof("using storage backend %s", nodeConfig.Spec.Storage.Type)
 	nodeComponents.Add(ctx, storageBackend)
 
+	// Will the cluster support multiple controllers, or just a single one?
+	singleController := c.SingleNode || !nodeConfig.Spec.Storage.IsJoinable()
+
 	// Assume a single active controller during startup
 	numActiveControllers := value.NewLatest[uint](1)
 
@@ -300,7 +303,7 @@ func (c *command) start(ctx context.Context) error {
 		return fmt.Errorf("failed to determine node name: %w", err)
 	}
 
-	if !c.SingleNode {
+	if !singleController {
 		nodeComponents.Add(ctx, &controller.K0sControllersLeaseCounter{
 			NodeName:              nodeName,
 			InvocationID:          c.K0sVars.InvocationID,
@@ -316,12 +319,12 @@ func (c *command) start(ctx context.Context) error {
 	}
 
 	// One leader elector per controller
-	if !c.SingleNode {
+	if singleController {
+		leaderElector = &leaderelector.Dummy{Leader: true}
+	} else {
 		// The name used to be hardcoded in the component itself
 		// At some point we need to rename this.
 		leaderElector = leaderelector.NewLeasePool(c.K0sVars.InvocationID, adminClientFactory, "k0s-endpoint-reconciler")
-	} else {
-		leaderElector = &leaderelector.Dummy{Leader: true}
 	}
 	nodeComponents.Add(ctx, leaderElector)
 
@@ -561,17 +564,17 @@ func (c *command) start(ctx context.Context) error {
 
 	if !slices.Contains(c.DisableComponents, constant.KubeSchedulerComponentName) {
 		clusterComponents.Add(ctx, &controller.Scheduler{
-			LogLevel:   c.LogLevels.KubeScheduler,
-			K0sVars:    c.K0sVars,
-			SingleNode: c.SingleNode,
+			LogLevel:              c.LogLevels.KubeScheduler,
+			K0sVars:               c.K0sVars,
+			DisableLeaderElection: singleController,
 		})
 	}
 
 	if !slices.Contains(c.DisableComponents, constant.KubeControllerManagerComponentName) {
 		clusterComponents.Add(ctx, &controller.Manager{
 			LogLevel:              c.LogLevels.KubeControllerManager,
 			K0sVars:               c.K0sVars,
-			SingleNode:            c.SingleNode,
+			DisableLeaderElection: singleController,
 			ServiceClusterIPRange: nodeConfig.Spec.Network.BuildServiceCIDR(nodeConfig.Spec.API.Address),
 			ExtraArgs:             c.KubeControllerManagerExtraArgs,
 		})
@@ -591,7 +594,7 @@ func (c *command) start(ctx context.Context) error {
 		K0sVars:            c.K0sVars,
 		KubeletExtraArgs:   c.KubeletExtraArgs,
 		AdminClientFactory: adminClientFactory,
-		EnableWorker:       c.EnableWorker,
+		Workloads:          c.EnableWorker,
 	})
 
 	restConfig, err := adminClientFactory.GetRESTConfig()

diff --git a/pkg/component/controller/autopilot.go b/pkg/component/controller/autopilot.go
@@ -38,7 +38,7 @@ type Autopilot struct {
 	K0sVars            *config.CfgVars
 	KubeletExtraArgs   string
 	AdminClientFactory kubernetes.ClientFactoryInterface
-	EnableWorker       bool
+	Workloads          bool
 }
 
 func (a *Autopilot) Init(ctx context.Context) error {
@@ -66,7 +66,7 @@ func (a *Autopilot) Start(ctx context.Context) error {
 		ManagerPort:         8899,
 		MetricsBindAddr:     "0",
 		HealthProbeBindAddr: "0",
-	}, logrus.WithFields(logrus.Fields{"component": "autopilot"}), a.EnableWorker, a.AdminClientFactory, autopilotClientFactory)
+	}, logrus.WithFields(logrus.Fields{"component": "autopilot"}), a.Workloads, a.AdminClientFactory, autopilotClientFactory)
 	if err != nil {
 		return fmt.Errorf("failed to create autopilot controller: %w", err)
 	}

diff --git a/pkg/component/controller/controllermanager.go b/pkg/component/controller/controllermanager.go
@@ -41,7 +41,7 @@ import (
 type Manager struct {
 	K0sVars               *config.CfgVars
 	LogLevel              string
-	SingleNode            bool
+	DisableLeaderElection bool
 	ServiceClusterIPRange string
 	ExtraArgs             string
 
@@ -132,7 +132,7 @@ func (a *Manager) Reconcile(_ context.Context, clusterConfig *v1beta1.ClusterCon
 			args[name] = value
 		}
 	}
-	if a.SingleNode {
+	if a.DisableLeaderElection {
 		args["leader-elect"] = "false"
 	}
 

diff --git a/pkg/component/controller/scheduler.go b/pkg/component/controller/scheduler.go
@@ -35,13 +35,13 @@ import (
 
 // Scheduler implement the component interface to run kube scheduler
 type Scheduler struct {
-	gid            int
-	K0sVars        *config.CfgVars
-	LogLevel       string
-	SingleNode     bool
-	supervisor     *supervisor.Supervisor
-	uid            int
-	previousConfig stringmap.StringMap
+	gid                   int
+	K0sVars               *config.CfgVars
+	LogLevel              string
+	DisableLeaderElection bool
+	supervisor            *supervisor.Supervisor
+	uid                   int
+	previousConfig        stringmap.StringMap
 }
 
 var _ manager.Component = (*Scheduler)(nil)
@@ -95,7 +95,7 @@ func (a *Scheduler) Reconcile(_ context.Context, clusterConfig *v1beta1.ClusterC
 		}
 		args[name] = value
 	}
-	if a.SingleNode {
+	if a.DisableLeaderElection {
 		args["leader-elect"] = "false"
 	}
 	args = clusterConfig.Spec.FeatureGates.BuildArgs(args, kubeSchedulerComponentName)