Kubernetes Custom Resource and Operator for PyTorch jobs

Overview

This repository contains the specification and implementation of PyTorchJob custom resource definition. Using this custom resource, users can create and manage PyTorch jobs like other built-in resources in Kubernetes. See CRD definition

Prerequisites

• Kubernetes >= 1.8
• kubectl

Installing PyTorch Operator

Please refer to the installation instructions in the Kubeflow user guide. This installs pytorchjob CRD and pytorch-operator controller to manage the lifecycle of PyTorch jobs.

Creating a PyTorch Job

You can create PyTorch Job by defining a PyTorchJob config file. See the manifests for the distributed MNIST example. You may change the config file based on your requirements.

cat examples/mnist/v1/pytorch_job_mnist_gloo.yaml

Deploy the PyTorchJob resource to start training:

kubectl create -f examples/mnist/v1/pytorch_job_mnist_gloo.yaml

You should now be able to see the created pods matching the specified number of replicas.

kubectl get pods -l pytorch-job-name=pytorch-dist-mnist-gloo

Training should run for about 10 epochs and takes 5-10 minutes on a cpu cluster. Logs can be inspected to see its training progress.

PODNAME=$(kubectl get pods -l pytorch-job-name=pytorch-dist-mnist-gloo,pytorch-replica-type=master -o name)
kubectl logs -f ${PODNAME}

Monitoring a PyTorch Job

kubectl get -o yaml pytorchjobs pytorch-dist-mnist-gloo

See the status section to monitor the job status. Here is sample output when the job is successfully completed.

apiVersion: v1
items:
- apiVersion: kubeflow.org/v1
  kind: PyTorchJob
  metadata:
    creationTimestamp: 2019-01-11T00:51:48Z
    generation: 1
    name: pytorch-dist-mnist-gloo
    namespace: default
    resourceVersion: "2146573"
    selfLink: /apis/kubeflow.org/v1/namespaces/kubeflow/pytorchjobs/pytorch-dist-mnist-gloo
    uid: 13ad0e7f-153b-11e9-b5c1-42010a80001e
  spec:
    pytorchReplicaSpecs:
      Master:
        replicas: 1
        restartPolicy: OnFailure
        template:
          spec:
            containers:
            - args:
              - --backend
              - gloo
              image: gcr.io/kubeflow-ci/pytorch-dist-mnist-test:v1.0
              name: pytorch
              resources:
                limits:
                  nvidia.com/gpu: "1"
      Worker:
        replicas: 1
        restartPolicy: OnFailure
        template:
          spec:
            containers:
            - args:
              - --backend
              - gloo
              image: gcr.io/kubeflow-ci/pytorch-dist-mnist-test:v1.0
              name: pytorch
              resources:
                limits:
                  nvidia.com/gpu: "1"
  status:
    completionTime: 2019-01-11T01:03:15Z
    conditions:
    - lastTransitionTime: 2019-01-11T00:51:48Z
      lastUpdateTime: 2019-01-11T00:51:48Z
      message: PyTorchJob pytorch-dist-mnist-gloo is created.
      reason: PyTorchJobCreated
      status: "True"
      type: Created
    - lastTransitionTime: 2019-01-11T00:57:22Z
      lastUpdateTime: 2019-01-11T00:57:22Z
      message: PyTorchJob pytorch-dist-mnist-gloo is running.
      reason: PyTorchJobRunning
      status: "False"
      type: Running
    - lastTransitionTime: 2019-01-11T01:03:15Z
      lastUpdateTime: 2019-01-11T01:03:15Z
      message: PyTorchJob pytorch-dist-mnist-gloo is successfully completed.
      reason: PyTorchJobSucceeded
      status: "True"
      type: Succeeded
    replicaStatuses:
      Master:
        succeeded: 1
      Worker:
        succeeded: 1
    startTime: 2019-01-11T00:57:22Z

Contributing

Please refer to the developer_guide.