add support for pipelines controller statefulset ordinals

docs/TektonPipeline.md

@@ -56,6 +56,7 @@ spec:
     threads-per-controller: 2
     kube-api-qps: 5.0
     kube-api-burst: 10
+    statefulset-ordinals: false
   options:
     disabled: false
     configMaps: {}
@@ -263,6 +264,7 @@ spec:
     threads-per-controller: 2
     kube-api-qps: 5.0
     kube-api-burst: 10
+    statefulset-ordinals: false
 ```
 These fields are optional and there is no default values. If user passes them, operator will include most of fields into the deployment `tekton-pipelines-controller` under the container `tekton-pipelines-controller` as arguments(duplicate name? No, container and deployment has the same name), otherwise pipelines controller's default values will be considered. and `buckets` field is updated into `config-leader-election` config-map under the namespace `tekton-pipelines`.
 
@@ -275,6 +277,11 @@ A high level descriptions are given here. To get the detailed information please
 * `threads-per-controller` - is the number of threads(aka worker) to use when processing the pipelines controller's workqueue, default value in pipelines controller is `2`
 * `kube-api-qps` - QPS indicates the maximum QPS to the cluster master from the REST client, default value in pipeline controller is `5.0`
 * `kube-api-burst` - maximum burst for throttle, default value in pipeline controller is `10`
+* `statefulset-ordinals` - enables StatefulSet Ordinals mode for the Tekton Pipelines Controller. When set to true, the Pipelines Controller is deployed as a StatefulSet, allowing for multiple replicas to be configured with a load-balancing mode. This ensures that the load is evenly distributed across replicas, and the number of buckets is enforced to match the number of replicas.
+Moreover, There are two mechanisms available for scaling for scaling Pipelines Controller horizontally: 
+- Using leader election, which allows for failover, but can result in hot-spotting.
+- Using StatefulSet ordinals, which doesn't allow for failover, but guarantees load is evenly spread across replicas.
+
 
 > #### Note:
 > * `kube-api-qps` and `kube-api-burst` will be multiplied by 2 in pipelines controller. To get the detailed information visit [Performance Configuration](https://tekton.dev/docs/pipelines/tekton-controller-performance-configuration/) guide

pkg/apis/operator/v1alpha1/tektonpipeline_defaults.go

@@ -150,6 +150,15 @@ func (p *Pipeline) setDefaults() {
 		p.EnableGitResolver = ptr.Bool(true)
 	}
 
+	// Statefulset Ordinals
+	// if StatefulSet Ordinals mode, buckets should be equal to replicas
+	if p.Performance.StatefulsetOrdinals != nil && *p.Performance.StatefulsetOrdinals {
+		if p.Performance.Replicas != nil && *p.Performance.Replicas > 1 {
+			replicas := uint(*p.Performance.Replicas)
+			p.Performance.Buckets = &replicas
+		}
+	}
+
 	// run platform specific defaulting
 	if IsOpenShiftPlatform() {
 		p.openshiftDefaulting()

pkg/apis/operator/v1alpha1/tektonpipeline_types.go

@@ -189,6 +189,8 @@ type PipelinePerformanceProperties struct {
 	// +optional
 	PipelinePerformanceLeaderElectionConfig `json:",inline"`
 	// +optional
+	PipelinePerformanceStatefulsetOrdinalsConfig `json:",inline"`
+	// +optional
 	PipelineDeploymentPerformanceArgs `json:",inline"`
 	// +optional
 	Replicas *int32 `json:"replicas,omitempty"`
@@ -201,6 +203,12 @@ type PipelinePerformanceLeaderElectionConfig struct {
 	Buckets *uint `json:"buckets,omitempty"`
 }
 
+// allow to configure pipelines controller ha mode to statefulset ordinals
+type PipelinePerformanceStatefulsetOrdinalsConfig struct {
+	//if is true, enable StatefulsetOrdinals mode
+	StatefulsetOrdinals *bool `json:"statefulset-ordinals,omitempty"`
+}
+
 // performance configurations to tune the performance of the pipeline controller
 // these properties will be added/updated as arguments in pipeline controller deployment
 // https://tekton.dev/docs/pipelines/tekton-controller-performance-configuration/

pkg/apis/operator/v1alpha1/tektonpipeline_validation.go

@@ -116,5 +116,15 @@ func (prof *PipelinePerformanceProperties) validate(path string) *apis.FieldErro
 		}
 	}
 
+	// check for StatefulsetOrdinals and Replicas
+	if prof.StatefulsetOrdinals != nil && *prof.StatefulsetOrdinals {
+		if prof.Replicas != nil {
+			replicas := uint(*prof.Replicas)
+			if *prof.Buckets != replicas {
+				errs = errs.Also(apis.ErrInvalidValue(*prof.Replicas, fmt.Sprintf("%s.replicas", path), "spec.performance.replicas must equal spec.performance.buckets for statefulset ordinals"))
+			}
+		}
+	}
+
 	return errs
 }

pkg/apis/operator/v1alpha1/tektonpipeline_validation_test.go

@@ -283,6 +283,13 @@ func TestTektonPipelinePerformancePropertiesValidate(t *testing.T) {
 		return &value
 	}
 
+	// return pointer value for replicas
+	getReplicas := func(value int32) *int32 {
+		return &value
+	}
+
+	statefulsetOrdinals := true
+
 	// validate buckets minimum range
 	tp.Spec.PipelineProperties.Performance = PipelinePerformanceProperties{}
 	tp.Spec.PipelineProperties.Performance.DisableHA = false
@@ -310,4 +317,26 @@ func TestTektonPipelinePerformancePropertiesValidate(t *testing.T) {
 	tp.Spec.PipelineProperties.Performance.Buckets = getBuckets(10)
 	errs = tp.Validate(context.TODO())
 	assert.Equal(t, "", errs.Error())
+
+	// validate buckets is equal to replicas when StatefulsetOrdinals is true
+	tp.Spec.PipelineProperties.Performance = PipelinePerformanceProperties{}
+	tp.Spec.PipelineProperties.Performance.DisableHA = false
+	bucketValue := uint(5)
+	tp.Spec.PipelineProperties.Performance.Buckets = getBuckets(bucketValue)
+	replicaValue := int32(5)
+	tp.Spec.PipelineProperties.Performance.Replicas = getReplicas(replicaValue)
+	tp.Spec.PipelineProperties.Performance.StatefulsetOrdinals = &statefulsetOrdinals
+	errs = tp.Validate(context.TODO())
+	assert.Equal(t, "", errs.Error())
+
+	// validate error when buckets is not equal to replica
+	tp.Spec.PipelineProperties.Performance = PipelinePerformanceProperties{}
+	tp.Spec.PipelineProperties.Performance.DisableHA = false
+	tp.Spec.PipelineProperties.Performance.StatefulsetOrdinals = &statefulsetOrdinals
+	bucketValue = uint(5)
+	tp.Spec.PipelineProperties.Performance.Buckets = getBuckets(bucketValue)
+	tp.Spec.PipelineProperties.Performance.Replicas = getReplicas(3)
+	errs = tp.Validate(context.TODO())
+	expectedErrorMessage := "invalid value: 3: spec.performance.replicas\nspec.performance.replicas must equal spec.performance.buckets for statefulset ordinals"
+	assert.Equal(t, expectedErrorMessage, errs.Error())
 }

pkg/reconciler/common/transformers.go

@@ -31,6 +31,7 @@ import (
 	batchv1 "k8s.io/api/batch/v1"
 	corev1 "k8s.io/api/core/v1"
 	rbacv1 "k8s.io/api/rbac/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
 	"knative.dev/pkg/logging"
@@ -1013,3 +1014,87 @@ func AddSecretData(data map[string][]byte, annotations map[string]string) mf.Tra
 		return nil
 	}
 }
+
+// ConvertDeploymentToStatefulSet converts a Deployment to a StatefulSet with given parameters
+func ConvertDeploymentToStatefulSet(controllerName, serviceName string) mf.Transformer {
+	return func(u *unstructured.Unstructured) error {
+		if u.GetKind() != "Deployment" || u.GetName() != controllerName {
+			return nil
+		}
+
+		d := &appsv1.Deployment{}
+		err := runtime.DefaultUnstructuredConverter.FromUnstructured(u.Object, d)
+		if err != nil {
+			return err
+		}
+
+		ss := &appsv1.StatefulSet{
+			TypeMeta: metav1.TypeMeta{
+				Kind:       "StatefulSet",
+				APIVersion: appsv1.SchemeGroupVersion.Group + "/" + appsv1.SchemeGroupVersion.Version,
+			},
+			ObjectMeta: d.ObjectMeta,
+			Spec: appsv1.StatefulSetSpec{
+				Selector:    d.Spec.Selector,
+				ServiceName: serviceName,
+				Template:    d.Spec.Template,
+				Replicas:    d.Spec.Replicas,
+				UpdateStrategy: appsv1.StatefulSetUpdateStrategy{
+					Type: appsv1.RollingUpdateStatefulSetStrategyType,
+				},
+			},
+		}
+
+		unstrObj, err := runtime.DefaultUnstructuredConverter.ToUnstructured(ss)
+		if err != nil {
+			return err
+		}
+
+		u.SetUnstructuredContent(unstrObj)
+
+		return nil
+	}
+}
+
+// AddStatefulEnvVars adds environment variables to the statefulset based on given parameters
+func AddStatefulEnvVars(controllerName, serviceName, statefulServiceEnvVar, controllerOrdinalEnvVar string) mf.Transformer {
+	return func(u *unstructured.Unstructured) error {
+		if u.GetKind() != "StatefulSet" || u.GetName() != controllerName {
+			return nil
+		}
+
+		ss := &appsv1.StatefulSet{}
+		err := runtime.DefaultUnstructuredConverter.FromUnstructured(u.Object, ss)
+		if err != nil {
+			return err
+		}
+
+		newEnvVars := []corev1.EnvVar{
+			{
+				Name:  statefulServiceEnvVar,
+				Value: serviceName,
+			},
+			{
+				Name: controllerOrdinalEnvVar,
+				ValueFrom: &corev1.EnvVarSource{
+					FieldRef: &corev1.ObjectFieldSelector{
+						FieldPath: "metadata.name",
+					},
+				},
+			},
+		}
+
+		if len(ss.Spec.Template.Spec.Containers) > 0 {
+			ss.Spec.Template.Spec.Containers[0].Env = append(ss.Spec.Template.Spec.Containers[0].Env, newEnvVars...)
+		}
+
+		unstrObj, err := runtime.DefaultUnstructuredConverter.ToUnstructured(ss)
+		if err != nil {
+			return err
+		}
+
+		u.SetUnstructuredContent(unstrObj)
+
+		return nil
+	}
+}

pkg/reconciler/kubernetes/tektoninstallerset/client/check.go

@@ -98,7 +98,9 @@ func verifyMainInstallerSets(iSets []v1alpha1.TektonInstallerSet) error {
 		static = true
 	}
 	if strings.Contains(iSets[0].GetName(), InstallerSubTypeDeployment) ||
-		strings.Contains(iSets[1].GetName(), InstallerSubTypeDeployment) {
+		strings.Contains(iSets[1].GetName(), InstallerSubTypeDeployment) ||
+		strings.Contains(iSets[0].GetName(), InstallerSubTypeStatefulset) ||
+		strings.Contains(iSets[1].GetName(), InstallerSubTypeStatefulset) {
 		deployment = true
 	}
 	if !(static && deployment) {

pkg/reconciler/kubernetes/tektoninstallerset/client/cleanup.go

@@ -57,7 +57,8 @@ func (i *InstallerSetClient) CleanupMainSet(ctx context.Context) error {
 
 	// now delete all deployment installerSet
 	for _, is := range list.Items {
-		if strings.Contains(is.GetName(), InstallerSubTypeDeployment) {
+		if strings.Contains(is.GetName(), InstallerSubTypeDeployment) ||
+			strings.Contains(is.GetName(), InstallerSubTypeStatefulset) {
 			logger.Debugf("deleting main-deployment installer set: %s", is.GetName())
 			err = i.clientSet.Delete(ctx, is.GetName(), metav1.DeleteOptions{
 				PropagationPolicy: &deletePropagationPolicy,
@@ -125,3 +126,37 @@ func (i *InstallerSetClient) cleanup(ctx context.Context, isType string) error {
 	}
 	return nil
 }
+
+func (i *InstallerSetClient) CleanupSubTypeDeployment(ctx context.Context) error {
+	return i.cleanupSubType(ctx, InstallerTypeMain, InstallerSubTypeDeployment)
+}
+
+func (i *InstallerSetClient) CleanupSubTypeStatefulset(ctx context.Context) error {
+	return i.cleanupSubType(ctx, InstallerTypeMain, InstallerSubTypeStatefulset)
+}
+
+func (i *InstallerSetClient) cleanupSubType(ctx context.Context, isType string, isSubType string) error {
+	logger := logging.FromContext(ctx).With("kind", i.resourceKind, "type", isType)
+
+	list, err := i.clientSet.List(ctx, metav1.ListOptions{LabelSelector: i.getSetLabels(isType)})
+	if err != nil {
+		return err
+	}
+
+	if len(list.Items) != 1 {
+		logger.Errorf("found more than 1 installerSet for %s something fishy, cleaning up all", isType)
+	}
+
+	for _, is := range list.Items {
+		if strings.Contains(is.GetName(), isSubType) {
+			logger.Debugf("deleting %s installer set: %s", isType, is.GetName())
+			err = i.clientSet.Delete(ctx, is.GetName(), metav1.DeleteOptions{
+				PropagationPolicy: &deletePropagationPolicy,
+			})
+			if err != nil {
+				return fmt.Errorf("failed to delete %s set: %s", isType, is.GetName())
+			}
+		}
+	}
+	return nil
+}

pkg/reconciler/kubernetes/tektoninstallerset/client/client.go

@@ -26,8 +26,9 @@ import (
 )
 
 const (
-	InstallerSubTypeStatic     = "static"
-	InstallerSubTypeDeployment = "deployment"
+	InstallerSubTypeStatic      = "static"
+	InstallerSubTypeDeployment  = "deployment"
+	InstallerSubTypeStatefulset = "statefulset"
 
 	InstallerTypeMain   = "main"
 	InstallerTypePre    = "pre"

pkg/reconciler/kubernetes/tektoninstallerset/client/create.go

@@ -60,6 +60,7 @@ func (i *InstallerSetClient) create(ctx context.Context, comp v1alpha1.TektonCom
 func (i *InstallerSetClient) makeMainSets(ctx context.Context, comp v1alpha1.TektonComponent, manifest *mf.Manifest) ([]v1alpha1.TektonInstallerSet, error) {
 	staticManifest := manifest.Filter(mf.Not(mf.ByKind("Deployment")), mf.Not(mf.ByKind("Service")))
 	deploymentManifest := manifest.Filter(mf.Any(mf.ByKind("Deployment"), mf.ByKind("Service")))
+	statefulSetManifest := manifest.Filter(mf.Any(mf.ByKind("StatefulSet"), mf.ByKind("Service")))
 
 	kind := strings.ToLower(strings.TrimPrefix(i.resourceKind, "Tekton"))
 	staticName := fmt.Sprintf("%s-%s-%s-", kind, InstallerTypeMain, InstallerSubTypeStatic)
@@ -78,6 +79,7 @@ func (i *InstallerSetClient) makeMainSets(ctx context.Context, comp v1alpha1.Tek
 	}
 
 	deployName := fmt.Sprintf("%s-%s-%s-", kind, InstallerTypeMain, InstallerSubTypeDeployment)
+
 	deploymentIS, err := i.makeInstallerSet(ctx, comp, &deploymentManifest, deployName, InstallerTypeMain, nil)
 	if err != nil {
 		return nil, err
@@ -87,6 +89,25 @@ func (i *InstallerSetClient) makeMainSets(ctx context.Context, comp v1alpha1.Tek
 	if err != nil {
 		return nil, err
 	}
+
+	statefulSet := false
+	if pipeline, ok := comp.(*v1alpha1.TektonPipeline); ok {
+		statefulSet = pipeline.Spec.Performance.StatefulsetOrdinals != nil && *pipeline.Spec.Performance.StatefulsetOrdinals
+	}
+	if statefulSet {
+		stsName := fmt.Sprintf("%s-%s-%s-", kind, InstallerTypeMain, InstallerSubTypeStatefulset)
+		stsIS, err := i.makeInstallerSet(ctx, comp, &statefulSetManifest, stsName, InstallerTypeMain, nil)
+		if err != nil {
+			return nil, err
+		}
+
+		stsIS, err = i.clientSet.Create(ctx, stsIS, metav1.CreateOptions{})
+		if err != nil {
+			return nil, err
+		}
+		return []v1alpha1.TektonInstallerSet{*staticIS, *deploymentIS, *stsIS}, nil
+	}
+
 	return []v1alpha1.TektonInstallerSet{*staticIS, *deploymentIS}, nil
 }
 

pkg/reconciler/kubernetes/tektonpipeline/reconcile.go

@@ -84,6 +84,20 @@ func (r *Reconciler) ReconcileKind(ctx context.Context, tp *v1alpha1.TektonPipel
 		return err
 	}
 
+	// Pipeline controller is deployed as statefulset, ensure deployment installerset is deleted
+	if tp.Spec.Performance.StatefulsetOrdinals != nil && *tp.Spec.Performance.StatefulsetOrdinals {
+		if err := r.installerSetClient.CleanupSubTypeDeployment(ctx); err != nil {
+			logger.Error("failed to delete main deployment installer set: %v", err)
+			return err
+		}
+	} else {
+		// Pipeline controller is deployed as deployment, ensure statefulset installerset is deleted
+		if err := r.installerSetClient.CleanupSubTypeStatefulset(ctx); err != nil {
+			logger.Error("failed to delete main statefulset installer set: %v", err)
+			return err
+		}
+	}
+
 	if err := r.extension.PreReconcile(ctx, tp); err != nil {
 		msg := fmt.Sprintf("PreReconciliation failed: %s", err.Error())
 		logger.Error(msg)