run worker process in launcher pod

deploy/v2beta1/mpi-operator.yaml

@@ -8190,6 +8190,11 @@ spec:
                 description: MPIReplicaSpecs contains maps from `MPIReplicaType` to
                   `ReplicaSpec` that specify the MPI replicas to run.
                 type: object
+              runLauncherAsWorker:
+                default: false
+                description: RunLauncherAsWorker indicates whether to run worker process
+                  in launcher Defaults to false.
+                type: boolean
               runPolicy:
                 description: RunPolicy encapsulates various runtime policies of the
                   job.

go.mod

@@ -15,7 +15,7 @@ require (
 	k8s.io/code-generator v0.27.4
 	k8s.io/klog v1.0.0
 	k8s.io/kube-openapi v0.0.0-20230501164219-8b0f38b5fd1f
-	k8s.io/utils v0.0.0-20230209194617-a36077c30491
+	k8s.io/utils v0.0.0-20240102154912-e7106e64919e
 	sigs.k8s.io/controller-runtime v0.15.1
 	sigs.k8s.io/scheduler-plugins v0.26.7
 	sigs.k8s.io/structured-merge-diff/v4 v4.2.3

go.sum

@@ -384,8 +384,8 @@ k8s.io/klog/v2 v2.90.1 h1:m4bYOKall2MmOiRaR1J+We67Do7vm9KiQVlT96lnHUw=
 k8s.io/klog/v2 v2.90.1/go.mod h1:y1WjHnz7Dj687irZUWR/WLkLc5N1YHtjLdmgWjndZn0=
 k8s.io/kube-openapi v0.0.0-20230501164219-8b0f38b5fd1f h1:2kWPakN3i/k81b0gvD5C5FJ2kxm1WrQFanWchyKuqGg=
 k8s.io/kube-openapi v0.0.0-20230501164219-8b0f38b5fd1f/go.mod h1:byini6yhqGC14c3ebc/QwanvYwhuMWF6yz2F8uwW8eg=
-k8s.io/utils v0.0.0-20230209194617-a36077c30491 h1:r0BAOLElQnnFhE/ApUsg3iHdVYYPBjNSSOMowRZxxsY=
-k8s.io/utils v0.0.0-20230209194617-a36077c30491/go.mod h1:OLgZIPagt7ERELqWJFomSt595RzquPNLL48iOWgYOg0=
+k8s.io/utils v0.0.0-20240102154912-e7106e64919e h1:eQ/4ljkx21sObifjzXwlPKpdGLrCfRziVtos3ofG/sQ=
+k8s.io/utils v0.0.0-20240102154912-e7106e64919e/go.mod h1:OLgZIPagt7ERELqWJFomSt595RzquPNLL48iOWgYOg0=
 sigs.k8s.io/apiserver-network-proxy/konnectivity-client v0.1.2 h1:trsWhjU5jZrx6UvFu4WzQDrN7Pga4a7Qg+zcfcj64PA=
 sigs.k8s.io/apiserver-network-proxy/konnectivity-client v0.1.2/go.mod h1:+qG7ISXqCDVVcyO8hLn12AKVYYUjM7ftlqsqmrhMZE0=
 sigs.k8s.io/controller-runtime v0.15.1 h1:9UvgKD4ZJGcj24vefUFgZFP3xej/3igL9BsOUTb/+4c=

manifests/base/kubeflow.org_mpijobs.yaml

@@ -8167,6 +8167,11 @@ spec:
                 description: MPIReplicaSpecs contains maps from `MPIReplicaType` to
                   `ReplicaSpec` that specify the MPI replicas to run.
                 type: object
+              runLauncherAsWorker:
+                default: false
+                description: RunLauncherAsWorker indicates whether to run worker process
+                  in launcher Defaults to false.
+                type: boolean
               runPolicy:
                 description: RunPolicy encapsulates various runtime policies of the
                   job.

pkg/apis/kubeflow/v2beta1/swagger.json

@@ -156,6 +156,10 @@
             "$ref": "#/definitions/v2beta1.ReplicaSpec"
           }
         },
+        "runLauncherAsWorker": {
+          "description": "RunLauncherAsWorker indicates whether to run worker process in launcher Defaults to false.",
+          "type": "boolean"
+        },
         "runPolicy": {
           "description": "RunPolicy encapsulates various runtime policies of the job.",
           "default": {},

pkg/apis/kubeflow/v2beta1/types.go

@@ -154,6 +154,12 @@ type MPIJobSpec struct {
 	// +kubebuilder:default:=1
 	SlotsPerWorker *int32 `json:"slotsPerWorker,omitempty"`
 
+	// RunLauncherAsWorker indicates whether to run worker process in launcher
+	// Defaults to false.
+	// +optional
+	// +kubebuilder:default:=false
+	RunLauncherAsWorker *bool `json:"runLauncherAsWorker,omitempty"`
+
 	// RunPolicy encapsulates various runtime policies of the job.
 	RunPolicy RunPolicy `json:"runPolicy,omitempty"`
 

pkg/controller/mpi_job_controller.go

@@ -53,7 +53,8 @@
 	"k8s.io/client-go/util/workqueue"
 	"k8s.io/klog"
 	"k8s.io/utils/clock"
 	"k8s.io/utils/pointer"
+	"k8s.io/utils/ptr"
 	schedclientset "sigs.k8s.io/scheduler-plugins/pkg/generated/clientset/versioned"
 	volcanoclient "volcano.sh/apis/pkg/client/clientset/versioned"
 
@@ -630,7 +631,7 @@
 	// We're done if the launcher either succeeded or failed.
 	done := launcher != nil && isJobFinished(launcher)
 	if !done {
-		_, err := c.getOrCreateService(mpiJob, newWorkersService(mpiJob))
+		_, err := c.getOrCreateService(mpiJob, newJobService(mpiJob))
 		if err != nil {
 			return fmt.Errorf("getting or creating Service to front workers: %w", err)
 		}
@@ -656,16 +657,6 @@
 				return err
 			}
 		}
-		if mpiJob.Spec.MPIImplementation == kubeflow.MPIImplementationIntel ||
-			mpiJob.Spec.MPIImplementation == kubeflow.MPIImplementationMPICH {
-			// The Intel and MPICH implementations require workers to communicate with the
-			// launcher through its hostname. For that, we create a Service which
-			// has the same name as the launcher's hostname.
-			_, err := c.getOrCreateService(mpiJob, newLauncherService(mpiJob))
-			if err != nil {
-				return fmt.Errorf("getting or creating Service to front launcher: %w", err)
-			}
-		}
 		if launcher == nil {
 			if mpiJob.Spec.LauncherCreationPolicy == kubeflow.LauncherCreationPolicyAtStartup || c.countReadyWorkerPods(worker) == len(worker) {
 				launcher, err = c.kubeClient.BatchV1().Jobs(namespace).Create(context.TODO(), c.newLauncherJob(mpiJob), metav1.CreateOptions{})
@@ -1279,17 +1270,30 @@
 // handleObject can discover the MPIJob resource that 'owns' it.
 func newConfigMap(mpiJob *kubeflow.MPIJob, workerReplicas int32) *corev1.ConfigMap {
 	var buffer bytes.Buffer
-	workersService := mpiJob.Name + workerSuffix
 	slots := 1
 	if mpiJob.Spec.SlotsPerWorker != nil {
 		slots = int(*mpiJob.Spec.SlotsPerWorker)
 	}
+	// note that pod.spec.dnsConfig also affect the svc resolution
+	// ref: https://kubernetes.io/docs/concepts/services-networking/dns-pod-service/
+	// launcher can be reach with hostname or service name
+	if ptr.Deref(mpiJob.Spec.RunLauncherAsWorker, false) {
+		name := mpiJob.Name + launcherSuffix
+		switch mpiJob.Spec.MPIImplementation {
+		case kubeflow.MPIImplementationOpenMPI:
+			buffer.WriteString(fmt.Sprintf("%s.%s.%s.svc slots=%d\n", name, mpiJob.Name, mpiJob.Namespace, slots))
+		case kubeflow.MPIImplementationIntel, kubeflow.MPIImplementationMPICH:
+			buffer.WriteString(fmt.Sprintf("%s.%s.%s.svc:%d\n", name, mpiJob.Name, mpiJob.Namespace, slots))
+		}
+	}
+
 	for i := 0; i < int(workerReplicas); i++ {
+		name := workerName(mpiJob, i)
 		switch mpiJob.Spec.MPIImplementation {
 		case kubeflow.MPIImplementationOpenMPI:
-			buffer.WriteString(fmt.Sprintf("%s%s-%d.%s.%s.svc slots=%d\n", mpiJob.Name, workerSuffix, i, workersService, mpiJob.Namespace, slots))
+			buffer.WriteString(fmt.Sprintf("%s.%s.%s.svc slots=%d\n", name, mpiJob.Name, mpiJob.Namespace, slots))
 		case kubeflow.MPIImplementationIntel, kubeflow.MPIImplementationMPICH:
-			buffer.WriteString(fmt.Sprintf("%s%s-%d.%s.%s.svc:%d\n", mpiJob.Name, workerSuffix, i, workersService, mpiJob.Namespace, slots))
+			buffer.WriteString(fmt.Sprintf("%s.%s.%s.svc:%d\n", name, mpiJob.Name, mpiJob.Namespace, slots))
 		}
 	}
 
@@ -1319,22 +1323,27 @@
 
 	var buffer bytes.Buffer
 	buffer.WriteString("#!/bin/sh\n")
-	workersService := mpiJob.Name + workerSuffix
+
+	// We don't check if launcher is running here, launcher should always be there or the job failed
+	if ptr.Deref(mpiJob.Spec.RunLauncherAsWorker, false) {
+		name := mpiJob.Name + launcherSuffix
+		buffer.WriteString(fmt.Sprintf("echo %s.%s.%s.svc\n", name, mpiJob.Name, mpiJob.Namespace))
+	}
+
 	for _, p := range runningPods {
-		buffer.WriteString(fmt.Sprintf("echo %s.%s.%s.svc\n", p.Name, workersService, p.Namespace))
+		buffer.WriteString(fmt.Sprintf("echo %s.%s.%s.svc\n", p.Name, mpiJob.Name, p.Namespace))
 	}
 
 	configMap.Data[discoverHostsScriptName] = buffer.String()
 }
 
-// newWorkersService creates a new workers' Service for an MPIJob resource.
-func newWorkersService(job *kubeflow.MPIJob) *corev1.Service {
-	return newService(job, job.Name+workerSuffix, defaultLabels(job.Name, worker))
-}
-
-// newLauncherService creates a new launcher's Service for an MPIJob resource.
-func newLauncherService(job *kubeflow.MPIJob) *corev1.Service {
-	return newService(job, job.Name+launcherSuffix, defaultLabels(job.Name, launcher))
+// newJobService creates a Service with the same name of Job for both launcher and worker pods
+func newJobService(job *kubeflow.MPIJob) *corev1.Service {
+	labels := map[string]string{
+		kubeflow.OperatorNameLabel: kubeflow.OperatorName,
+		kubeflow.JobNameLabel:      job.Name,
+	}
+	return newService(job, job.Name, labels)
 }
 
 func newService(job *kubeflow.MPIJob, name string, selector map[string]string) *corev1.Service {
@@ -1416,12 +1425,19 @@
 	}
 	podTemplate.Labels[kubeflow.ReplicaIndexLabel] = strconv.Itoa(index)
 	podTemplate.Spec.Hostname = name
-	podTemplate.Spec.Subdomain = mpiJob.Name + workerSuffix // Matches workers' Service name.
+	podTemplate.Spec.Subdomain = mpiJob.Name // Matches job' Service name.
 	if podTemplate.Spec.HostNetwork {
 		// Allows resolution of worker hostnames without needing to include the
 		// namespace or cluster domain.
 		podTemplate.Spec.DNSPolicy = corev1.DNSClusterFirstWithHostNet
 	}
+	// The Intel and MPICH implementations require workers to communicate with the launcher through its hostname.
+	searche := fmt.Sprintf("%s.%s.svc.cluster.local", mpiJob.Name, mpiJob.Namespace)
+	if podTemplate.Spec.DNSConfig == nil {
+		podTemplate.Spec.DNSConfig = &corev1.PodDNSConfig{Searches: []string{searche}}
+	} else {
+		podTemplate.Spec.DNSConfig.Searches = append(podTemplate.Spec.DNSConfig.Searches, searche)
+	}
 	setRestartPolicy(podTemplate, mpiJob.Spec.MPIReplicaSpecs[kubeflow.MPIReplicaTypeWorker])
 
 	container := &podTemplate.Spec.Containers[0]
@@ -1494,7 +1510,7 @@
 		c.PodGroupCtrl.decoratePodTemplateSpec(podTemplate, mpiJob.Name)
 	}
 	podTemplate.Spec.Hostname = launcherName
-	podTemplate.Spec.Subdomain = mpiJob.Name + workerSuffix // Matches workers' Service name.
+	podTemplate.Spec.Subdomain = mpiJob.Name // Matches job' Service name.
 	if podTemplate.Spec.HostNetwork {
 		// Allows resolution of worker hostnames without needing to include the
 		// namespace or cluster domain.