+++ title = "TensorFlow Training (TFJob)" linkTitle = "TensorFlow Training (TFJob)" description = "" weight = 60 +++ This page describes TFJob for training a machine learning model with TensorFlow. ## What is TFJob? TFJob is a Kubernetes [custom resource](https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/custom-resources/) that you can use to run TensorFlow training jobs on Kubernetes. The Kubeflow implementation of TFJob is in [`tf-operator`](https://github.com/kubeflow/tf-operator). A TFJob is a resource with a YAML representation like the one below (edit to use the container image and command for your own training code): ```yaml apiVersion: kubeflow.org/v1beta1 kind: TFJob metadata: generateName: tfjob namespace: kubeflow spec: tfReplicaSpecs: PS: replicas: 1 restartPolicy: OnFailure template: spec: containers: - name: tensorflow image: gcr.io/your-project/your-image command: - python - -m - trainer.task - --batch_size=32 - --training_steps=1000 Worker: replicas: 3 restartPolicy: OnFailure template: spec: containers: - name: tensorflow image: gcr.io/your-project/your-image command: - python - -m - trainer.task - --batch_size=32 - --training_steps=1000 Master: replicas: 1 restartPolicy: OnFailure template: spec: containers: - name: tensorflow image: gcr.io/your-project/your-image command: - python - -m - trainer.task - --batch_size=32 - --training_steps=1000 ``` If you want to give your TFJob pods access to credentials secrets, such as the GCP credentials automatically created when you do a GKE-based Kubeflow installation, you can mount and use a secret like this: ```yaml apiVersion: kubeflow.org/v1beta1 kind: TFJob metadata: generateName: tfjob namespace: kubeflow spec: tfReplicaSpecs: PS: replicas: 1 restartPolicy: OnFailure template: spec: containers: - name: tensorflow image: gcr.io/your-project/your-image command: - python - -m - trainer.task - --batch_size=32 - --training_steps=1000 env: - name: GOOGLE_APPLICATION_CREDENTIALS value: "/etc/secrets/user-gcp-sa.json" volumeMounts: - name: sa mountPath: "/etc/secrets" readOnly: true volumes: - name: sa secret: secretName: user-gcp-sa Worker: replicas: 1 restartPolicy: OnFailure template: spec: containers: - name: tensorflow image: gcr.io/your-project/your-image command: - python - -m - trainer.task - --batch_size=32 - --training_steps=1000 env: - name: GOOGLE_APPLICATION_CREDENTIALS value: "/etc/secrets/user-gcp-sa.json" volumeMounts: - name: sa mountPath: "/etc/secrets" readOnly: true volumes: - name: sa secret: secretName: user-gcp-sa Master: replicas: 1 restartPolicy: OnFailure template: spec: containers: - name: tensorflow image: gcr.io/your-project/your-image command: - python - -m - trainer.task - --batch_size=32 - --training_steps=1000 env: - name: GOOGLE_APPLICATION_CREDENTIALS value: "/etc/secrets/user-gcp-sa.json" volumeMounts: - name: sa mountPath: "/etc/secrets" readOnly: true volumes: - name: sa secret: secretName: user-gcp-sa ``` If you are not familiar with Kubernetes resources please refer to the page [Understanding Kubernetes Objects](https://kubernetes.io/docs/concepts/overview/working-with-objects/kubernetes-objects/). What makes TFJob different from built in [controllers](https://kubernetes.io/docs/concepts/workloads/controllers/) is the TFJob spec is designed to manage [distributed TensorFlow training jobs](https://www.tensorflow.org/deploy/distributed). A distributed TensorFlow job typically contains 0 or more of the following processes * **Chief** The chief is responsible for orchestrating training and performing tasks like checkpointing the model. * **Ps** The ps are parameter servers; these servers provide a distributed data store for the model parameters. * **Worker** The workers do the actual work of training the model. In some cases, worker 0 might also act as the chief. * **Evaluator** The evaluators can be used to compute evaluation metrics as the model is trained. The field **tfReplicaSpecs** in TFJob spec contains a map from the type of replica (as listed above) to the **TFReplicaSpec** for that replica. **TFReplicaSpec** consists of 3 fields * **replicas** The number of replicas of this type to spawn for this TFJob. * **template** A [PodTemplateSpec](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.11/#podtemplatespec-v1-core) that describes the pod to create for each replica. * **The pod must include a container named tensorflow**. * **restartPolicy** Determines whether pods will be restarted when they exit. The allowed values are as follows * **Always** means the pod will always be restarted. This policy is good for parameter servers since they never exit and should always be restarted in the event of failure. * **OnFailure** means the pod will be restarted if the pod exits due to failure. * A non-zero exit code indicates a failure. * An exit code of 0 indicates success and the pod will not be restarted. * This policy is good for chief and workers. * **ExitCode** means the restart behavior is dependent on the exit code of the tensorflow container as follows * **0** indicates the process completed successfully and will not be restarted. * **1-127** indicates a permanent error and the container will not be restarted. * **128-255** indicates a retryable error and the container will be restarted. This policy is good for the chief and workers. * **Never** means pods that terminate will never be restarted. This policy should rarely be used because Kubernetes will terminate pods for any number of reasons (e.g. node becomes unhealthy) and this will prevent the job from recovering. ## Quick start ### Submitting a TensorFlow training job **Note:** Before submitting a training job, you should have [deployed kubeflow to your cluster](#deploy-kubeflow). Doing so ensures that the [`TFJob` custom resource](https://github.com/kubeflow/tf-operator) is available when you submit the training job. We treat each TensorFlow job as a [component](https://ksonnet.io/docs/tutorial#2-generate-and-deploy-an-app-component) in your APP. ### Running the TfCnn example Kubeflow ships with a [ksonnet prototype](https://ksonnet.io/docs/concepts#prototype) suitable for running the [TensorFlow CNN Benchmarks](https://github.com/tensorflow/benchmarks/tree/master/scripts/tf_cnn_benchmarks). You can also use this prototype to generate a component which you can then customize for your jobs. Create the component (update version as appropriate). ``` CNN_JOB_NAME=mycnnjob VERSION=v0.4.0 ks init ${CNN_JOB_NAME} cd ${CNN_JOB_NAME} ks registry add kubeflow-git github.com/kubeflow/kubeflow/tree/${VERSION}/kubeflow ks pkg install kubeflow-git/examples ``` Choose a tf-job prototype from the following list of available prototypes, to match the CRD you're using: > Type `ks prototype list` to list all available prototypes * `io.ksonnet.pkg.tf-job-operator` - A TensorFlow job operator. * `io.ksonnet.pkg.tf-job-simple` - A simple TFJob to run CNN benchmark * `io.ksonnet.pkg.tf-job-simple-v1beta1` - A simple TFJob to run CNN benchmark Run the `generate` command: ``` ks generate tf-job-simple-v1beta1 ${CNN_JOB_NAME} --name=${CNN_JOB_NAME} ``` Submit the job: ``` export KF_ENV=default ks apply ${KF_ENV} -c ${CNN_JOB_NAME} ``` The `KF_ENV` environment variable represents a conceptual deployment environment such as development, test, staging, or production, as defined by ksonnet. For this example, we use the `default` environment. You can read more about Kubeflow's use of ksonnet in the Kubeflow [ksonnet component guide](/docs/components/ksonnet/). Monitor the job (see the [TFJob docs](/docs/components/tftraining/#monitoring-your-job)): ``` kubectl get -n kubeflow -o yaml tfjobs ${CNN_JOB_NAME} ``` Delete it ``` ks delete ${KF_ENV} -c ${CNN_JOB_NAME} ``` ### Customizing the TFJob Generating a component as in the previous step will create a file named ``` components/${CNN_JOB_NAME}.jsonnet ``` A jsonnet file is basically a json file defining the manifest for your TFJob. You can modify this manifest to run your jobs. Typically you will want to change the following values 1. Change the image to point to the docker image containing your code 1. Change the number and types of replicas 1. Change the resources (requests and limits) assigned to each resource 1. Set any environment variables * For example, you might need to configure various environment variables to talk to datastores like GCS or S3 1. Attach PVs if you want to use PVs for storage. ### Accessing the TFJob dashboard The TFJob dashboard is available at `/tfjobs/ui/`. Specifically: * If you're using the central Kubeflow UI, you can access the TFJob dashboard by clicking **TFJOB DASHBOARD**: ![Central UI](/docs/images/central-ui.png) * If you followed the guide to [deploying Kubeflow on GCP](/docs/gke/deploy/), you can access the TFJob dashboard at the following URL: ``` https://.endpoints..cloud.goog/tfjobs/ui/ ``` * If you're using portforwarding, you can access the TFJob dashboard at the following URL: ``` http://localhost:8080/tfjobs/ui/ ``` See more details about [accessing the Kubeflow UIs](/docs/other-guides/accessing-uis). ## Using GPUs To use GPUs your cluster must be configured to use GPUs. * Nodes must have GPUs attached * K8s cluster must recognize the `nvidia.com/gpu` resource type * GPU drivers must be installed on the cluster. * For more information: * [K8s Instructions For Scheduling GPUs](https://kubernetes.io/docs/tasks/manage-gpus/scheduling-gpus/) * [GKE Instructions](https://cloud.google.com/kubernetes-engine/docs/concepts/gpus) * [EKS Instructions](https://docs.aws.amazon.com/eks/latest/userguide/gpu-ami.html) To attach GPUs specify the GPU resource on the container in the replicas that should contain the GPUs; for example. ```yaml apiVersion: "kubeflow.org/v1beta1" kind: "TFJob" metadata: name: "tf-smoke-gpu" spec: tfReplicaSpecs: PS: replicas: 1 template: metadata: creationTimestamp: null spec: containers: - args: - python - tf_cnn_benchmarks.py - --batch_size=32 - --model=resnet50 - --variable_update=parameter_server - --flush_stdout=true - --num_gpus=1 - --local_parameter_device=cpu - --device=cpu - --data_format=NHWC image: gcr.io/kubeflow/tf-benchmarks-cpu:v20171202-bdab599-dirty-284af3 name: tensorflow ports: - containerPort: 2222 name: tfjob-port resources: limits: cpu: '1' workingDir: /opt/tf-benchmarks/scripts/tf_cnn_benchmarks restartPolicy: OnFailure Worker: replicas: 1 template: metadata: creationTimestamp: null spec: containers: - args: - python - tf_cnn_benchmarks.py - --batch_size=32 - --model=resnet50 - --variable_update=parameter_server - --flush_stdout=true - --num_gpus=1 - --local_parameter_device=cpu - --device=gpu - --data_format=NHWC image: gcr.io/kubeflow/tf-benchmarks-gpu:v20171202-bdab599-dirty-284af3 name: tensorflow ports: - containerPort: 2222 name: tfjob-port resources: limits: nvidia.com/gpu: 1 workingDir: /opt/tf-benchmarks/scripts/tf_cnn_benchmarks restartPolicy: OnFailure ``` Follow TensorFlow's [instructions](https://www.tensorflow.org/tutorials/using_gpu) for using GPUs. ## Monitoring your job To get the status of your job ```bash kubectl get -o yaml tfjobs ${JOB} ``` Here is sample output for an example job ```yaml apiVersion: v1 items: - apiVersion: kubeflow.org/v1beta1 kind: TFJob metadata: creationTimestamp: 2019-02-02T15:24:54Z generation: 1 name: tf-smoke-gpu resourceVersion: "43282271" selfLink: /apis/kubeflow.org/v1beta1/namespaces/kubeflow/tfjobs/tf-smoke-gpu uid: b0e5e256-26fe-11e9-a020-509a4c3d1d6d spec: cleanPodPolicy: Running tfReplicaSpecs: PS: replicas: 1 restartPolicy: Never template: metadata: creationTimestamp: null spec: containers: - args: - python - tf_cnn_benchmarks.py - --batch_size=32 - --model=resnet50 - --variable_update=parameter_server - --flush_stdout=true - --num_gpus=1 - --local_parameter_device=cpu - --device=cpu - --data_format=NHWC image: gcr.io/kubeflow/tf-benchmarks-cpu:v20171202-bdab599-dirty-284af3 name: tensorflow ports: - containerPort: 2222 name: tfjob-port resources: limits: cpu: "1" workingDir: /opt/tf-benchmarks/scripts/tf_cnn_benchmarks restartPolicy: OnFailure Worker: replicas: 1 restartPolicy: Never template: metadata: creationTimestamp: null spec: containers: - args: - python - tf_cnn_benchmarks.py - --batch_size=32 - --model=resnet50 - --variable_update=parameter_server - --flush_stdout=true - --num_gpus=1 - --local_parameter_device=cpu - --device=gpu - --data_format=NHWC image: gcr.io/kubeflow/tf-benchmarks-gpu:v20171202-bdab599-dirty-284af3 name: tensorflow ports: - containerPort: 2222 name: tfjob-port resources: limits: nvidia.com/gpu: "1" workingDir: /opt/tf-benchmarks/scripts/tf_cnn_benchmarks restartPolicy: OnFailure status: conditions: - lastTransitionTime: 2019-02-02T15:24:54Z lastUpdateTime: 2019-02-02T15:24:54Z message: TFJob tf-smoke-gpu is created. reason: TFJobCreated status: "True" type: Created - lastTransitionTime: 2019-02-02T15:25:00Z lastUpdateTime: 2019-02-02T15:25:00Z message: TFJob tf-smoke-gpu is running. reason: TFJobRunning status: "True" type: Running replicaStatuses: PS: active: 1 Worker: active: 1 startTime: 2019-02-02T15:24:56Z kind: List metadata: resourceVersion: "" selfLink: "" ``` ### Conditions A TFJob has a TFJobStatus, which has an array of TFJobConditions through which the TFJob has or has not passed. Each element of the TFJobCondition array has six possible fields: * The **lastUpdateTime** field provides the last time this condition was updated. * The **lastTransitionTime** field provides the last time the condition transitioned from one status to another. * The **message** field is a human readable message indicating details about the transition. * The **reason** field is a unique, one-word, CamelCase reason for the condition's last transition. * The **status** field is a string with possible values "True", "False", and "Unknown". * The **type** field is a string with the following possible values: * **TFJobCreated** means the tfjob has been accepted by the system, but one or more of the pods/services has not been started. * **TFJobRunning** means all sub-resources (e.g. services/pods) of this TFJob have been successfully scheduled and launched and the job is running. * **TFJobRestarting** means one or more sub-resources (e.g. services/pods) of this TFJob had a problem and is being restarted. * **TFJobSucceeded** means the job completed successfully. * **TFJobFailed** means the job has failed. Success or failure of a job is determined as follows * If a job has a **chief** success or failure is determined by the status of the chief. * If a job has no chief success or failure is determined by the workers. * In both cases the TFJob succeeds if the process being monitored exits with exit code 0. * In the case of non-zero exit code the behavior is determined by the restartPolicy for the replica. * If the restartPolicy allows for restarts then the process will just be restarted and the TFJob will continue to execute. * For the restartPolicy ExitCode the behavior is exit code dependent. * If the restartPolicy doesn't allow restarts a non-zero exit code is considered a permanent failure and the job is marked failed. * For the restartPolicy ExitCode the behavior is exit code dependent. ### tfReplicaStatuses tfReplicaStatuses provides a map indicating the number of pods for each replica in a given state. There are three possible states * **Active** is the number of currently running pods. * **Succeeded** is the number of pods that completed successfully. * **Failed** is the number of pods that completed with an error. ### Events During execution, TFJob will emit events to indicate whats happening such as the creation/deletion of pods and services. Kubernetes doesn't retain events older than 1 hour by default. To see recent events for a job run ``` kubectl describe tfjobs ${JOB} ``` which will produce output like ``` Name: tfjob2 Namespace: kubeflow Labels: app.kubernetes.io/deploy-manager=ksonnet Annotations: ksonnet.io/managed={"pristine":"H4sIAAAAAAAA/+yRz27UMBDG7zzGnJ3NbkoFjZQTqEIcYEUrekBVNHEmWbOObY3HqcJq3x05UC1/ngCJHKKZbz6P5e93AgzmM3E03kENx9TRYP3TxvNYzju04YAVKDga10MN97fvfQcKJhLsURDqEzicCGqQ4avvsjX3MaCm... API Version: kubeflow.org/v1beta1 Kind: TFJob Metadata: Cluster Name: Creation Timestamp: 2018-07-29T02:46:53Z Generation: 1 Resource Version: 26872 Self Link: /apis/kubeflow.org/v1beta1/namespaces/kubeflow/tfjobs/tfjob2 UID: a6bc7b6f-92d9-11e8-b3ca-42010a80019c Spec: Tf Replica Specs: PS: Replicas: 1 Template: Metadata: Creation Timestamp: Spec: Containers: Args: python tf_cnn_benchmarks.py --batch_size=32 --model=resnet50 --variable_update=parameter_server --flush_stdout=true --num_gpus=1 --local_parameter_device=cpu --device=cpu --data_format=NHWC Image: gcr.io/kubeflow/tf-benchmarks-cpu:v20171202-bdab599-dirty-284af3 Name: tensorflow Ports: Container Port: 2222 Name: tfjob-port Resources: Working Dir: /opt/tf-benchmarks/scripts/tf_cnn_benchmarks Restart Policy: OnFailure Worker: Replicas: 1 Template: Metadata: Creation Timestamp: Spec: Containers: Args: python tf_cnn_benchmarks.py --batch_size=32 --model=resnet50 --variable_update=parameter_server --flush_stdout=true --num_gpus=1 --local_parameter_device=cpu --device=cpu --data_format=NHWC Image: gcr.io/kubeflow/tf-benchmarks-cpu:v20171202-bdab599-dirty-284af3 Name: tensorflow Ports: Container Port: 2222 Name: tfjob-port Resources: Working Dir: /opt/tf-benchmarks/scripts/tf_cnn_benchmarks Restart Policy: OnFailure Status: Conditions: Last Transition Time: 2018-07-29T02:46:55Z Last Update Time: 2018-07-29T02:46:55Z Message: TFJob tfjob2 is running. Reason: TFJobRunning Status: True Type: Running Start Time: 2018-07-29T02:46:55Z Tf Replica Statuses: PS: Active: 1 Worker: Active: 1 Events: Type Reason Age From Message ---- ------ ---- ---- ------- Warning SettedPodTemplateRestartPolicy 19s (x2 over 19s) tf-operator Restart policy in pod template will be overwritten by restart policy in replica spec Normal SuccessfulCreatePod 19s tf-operator Created pod: tfjob2-worker-0 Normal SuccessfulCreateService 19s tf-operator Created service: tfjob2-worker-0 Normal SuccessfulCreatePod 19s tf-operator Created pod: tfjob2-ps-0 Normal SuccessfulCreateService 19s tf-operator Created service: tfjob2-ps-0 ``` Here the events indicate that the pods and services were successfully created. ## TensorFlow Logs Logging follows standard K8s logging practices. You can use kubectl to get standard output/error for any pods that haven't been **deleted**. First find the pod created by the job controller for the replica of interest. Pods will be named ``` ${JOBNAME}-${REPLICA-TYPE}-${INDEX} ``` Once you've identified your pod you can get the logs using kubectl. ``` kubectl logs ${PODNAME} ``` The **CleanPodPolicy** in the TFJob spec controls deletion of pods when a job terminates. The policy can be one of the following values * The **Running** policy means that only pods still running when a job completes (e.g. parameter servers) will be deleted immediately; completed pods will not be deleted so that the logs will be preserved. This is the default value. * The **All** policy means all pods even completed pods will be deleted immediately when the job finishes. * The **None** policy means that no pods will be deleted when the job completes. If your cluster takes advantage of K8s [cluster logging](https://kubernetes.io/docs/concepts/cluster-administration/logging/) then your logs may also be shipped to an appropriate data store for further analysis. ### Stackdriver on GKE See the guide to [logging and monitoring](/docs/gke/monitoring/) for instructions on getting logs using Stackdriver. As described in the guide to [logging and monitoring](https://www.kubeflow.org/docs/gke/monitoring/#filter-with-labels), it's possible to fetch the logs for a particular replica based on pod labels. Using the Stackdriver UI you can use a query like ``` resource.type="k8s_container" resource.labels.cluster_name="${CLUSTER}" metadata.userLabels.tf_job_name="${JOB_NAME}" metadata.userLabels.tf-replica-type="${TYPE}" metadata.userLabels.tf-replica-index="${INDEX}" ``` Alternatively using gcloud ``` QUERY="resource.type=\"k8s_container\" " QUERY="${QUERY} resource.labels.cluster_name=\"${CLUSTER}\" " QUERY="${QUERY} metadata.userLabels.tf_job_name=\"${JOB_NAME}\" " QUERY="${QUERY} metadata.userLabels.tf-replica-type=\"${TYPE}\" " QUERY="${QUERY} metadata.userLabels.tf-replica-index=\"${INDEX}\" " gcloud --project=${PROJECT} logging read \ --freshness=24h \ --order asc ${QUERY} ``` ## Troubleshooting Here are some steps to follow to troubleshoot your job 1. Is a status present for your job? Run the command ```yaml kubectl -n ${NAMESPACE} get tfjobs -o yaml ${JOB_NAME} ``` * If the resulting output doesn't include a status for your job then this typically indicates the job spec is invalid. * If the TFJob spec is invalid there should be a log message in the tf operator logs ``` kubectl -n ${KUBEFLOW_NAMESPACE} logs `kubectl get pods --selector=name=tf-job-operator -o jsonpath='{.items[0].metadata.name}'` ``` * **KUBEFLOW_NAMESPACE** Is the namespace you deployed the TFJob operator in. 1. Check the events for your job to see if the pods were created * There are a number of ways to get the events; if your job is less than **1 hour old** then you can do ``` kubectl -n ${NAMESPACE} describe tfjobs -o yaml ${JOB_NAME} ``` * The bottom of the output should include a list of events emitted by the job; e.g. ```yaml Events: Type Reason Age From Message ---- ------ ---- ---- ------- Warning SettedPodTemplateRestartPolicy 19s (x2 over 19s) tf-operator Restart policy in pod template will be overwritten by restart policy in replica spec Normal SuccessfulCreatePod 19s tf-operator Created pod: tfjob2-worker-0 Normal SuccessfulCreateService 19s tf-operator Created service: tfjob2-worker-0 Normal SuccessfulCreatePod 19s tf-operator Created pod: tfjob2-ps-0 Normal SuccessfulCreateService 19s tf-operator Created service: tfjob2-ps-0 ``` * Kubernetes only preserves events for **1 hour** (see [kubernetes/kubernetes#52521](https://github.com/kubernetes/kubernetes/issues/52521)) * Depending on your cluster setup events might be persisted to external storage and accessible for longer periods * On GKE events are persisted in stackdriver and can be accessed using the instructions in the previous section. * If the pods and services aren't being created then this suggests the TFJob isn't being processed; common causes are * The TFJob spec is invalid (see above) * The TFJob operator isn't running 1. Check the events for the pods to ensure they are scheduled. * There are a number of ways to get the events; if your pod is less than **1 hour old** then you can do ``` kubectl -n ${NAMESPACE} describe pods ${POD_NAME} ``` * The bottom of the output should contain events like the following ```yaml Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal Scheduled 18s default-scheduler Successfully assigned tfjob2-ps-0 to gke-jl-kf-v0-2-2-default-pool-347936c1-1qkt Normal SuccessfulMountVolume 17s kubelet, gke-jl-kf-v0-2-2-default-pool-347936c1-1qkt MountVolume.SetUp succeeded for volume "default-token-h8rnv" Normal Pulled 17s kubelet, gke-jl-kf-v0-2-2-default-pool-347936c1-1qkt Container image "gcr.io/kubeflow/tf-benchmarks-cpu:v20171202-bdab599-dirty-284af3" already present on machine Normal Created 17s kubelet, gke-jl-kf-v0-2-2-default-pool-347936c1-1qkt Created container Normal Started 16s kubelet, gke-jl-kf-v0-2-2-default-pool-347936c1-1qkt Started container ``` * Some common problems that can prevent a container from starting are * Insufficient resources to schedule the pod * The pod tries to mount a volume (or secret) that doesn't exist or is unavailable * The docker image doesn't exist or can't be accessed (e.g due to permission issues) 1. If the containers start; check the logs of the containers following the instructions in the previous section. ## More information * Explore the [TFJob reference documentation](/docs/reference#tfjob). * See how to [run a job with gang-scheduling](/docs/other-guides/job-scheduling).