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Training MNIST

Training MNIST

This example guides you through the process of taking an example model, modifying it to run better within Kubeflow, and serving the resulting trained model.

Prerequisites

Before we get started there a few requirements.

Deploy Kubeflow

Follow the Getting Started Guide to deploy Kubeflow

Local Setup

You also need the following command line tools:

kubectl
ksonnet

To run the client at the end of the example, you must have requirements.txt intalled in your active python environment.

pip install -r requirements.txt

NOTE: These instructions rely on Github, and may cause issues if behind a firewall with many Github users.

Modifying existing examples

Many examples online use models that are unconfigurable, or don't work well in distributed mode. We will modify one of these examples to be better suited for distributed training and model serving.

Prepare model

There is a delta between existing distributed mnist examples and what's needed to run well as a TFJob.

Basically, we must:

Add options in order to make the model configurable.
Use tf.estimator.train_and_evaluate to enable model exporting and serving.
Define serving signatures for model serving.

The resulting model is model.py.

Build and push model image.

With our code ready, we will now build/push the docker image.

DOCKER_URL=docker.io/reponame/mytfmodel # Put your docker registry here
docker build . --no-cache  -f Dockerfile.model -t ${DOCKER_URL}

docker push ${DOCKER_URL}

Preparing your Kubernetes Cluster

With our data and workloads ready, now the cluster must be prepared. We will be deploying the TF Operator, and Argo to help manage our training job.

In the following instructions we will install our required components to a single namespace. For these instructions we will assume the chosen namespace is tfworkflow:

Training your model

Local storage

Let's start by runing the training job on Kubeflow and storing the model in a directory local to the pod e.g. '/tmp'. This is useful as a smoke test to ensure everything works. Since /tmp is not a filesystem external to the container, all data is lost once the job finishes. So to make the model available after the job finishes we will need to use an external filesystem like GCS or S3 as discussed in the next section.

KSENV=local
cd ks_app
ks env add ${KSENV}

Give the job a name to indicate it is running locally

ks param set --env=${KSENV} train name mnist-train-local

Point the job at your custom training image

ks param set --env=${KSENV} train image $DOCKER_URL

Configure a filepath for the exported model and checkpoints.

ks param set --env=${KSENV} train modelDir ./output
ks param set --env=${KSENV} train exportDir ./output/export

You can now submit the job

ks apply ${KSENV} -c train

And you can check the job

kubectl get tfjobs -o yaml mnist-train-local

And to check the logs

kubectl logs mnist-train-local-chief-0

Storing the model in a directory inside the container isn't useful because the directory is lost as soon as the pod is deleted.

So in the next sections we cover saving the model on a suitable filesystem like GCS or S3.

Using GCS

In this section we describe how to save the model to Google Cloud Storage (GCS).

Storing the model in GCS has the advantages

The model is readily available after the job finishes
We can run distributed training
- Distributed training requires a storage system accessible to all the machines

Lets start by creating an environment to store parameters particular to writing the model to GCS and running distributed.

KSENV=distributed
cd ks_app
ks env add ${KSENV}

Set an environment variable that points to your GCP project Id

PROJECT=<your project id>

Create a bucket on GCS to store our model. The name must be unique across all GCS buckets

BUCKET=$KSENV-$(date +%s)
gsutil mb gs://$BUCKET/

Give the job a different name (to distinguish it from your job which didn't use GCS)

ks param set --env=${KSENV} train name mnist-train-dist

Next we configure it to run distributed by setting the number of parameter servers and workers to use.

ks param set --env=${KSENV} train numPs 1
ks param set --env=${KSENV} train numWorkers 2

Now we need to configure parameters telling the code to save the model to GCS.

MODEL_PATH=my-model
ks param set --env=${KSENV} train modelDir gs://${BUCKET}/${MODEL_PATH}
ks param set --env=${KSENV} train exportDir gs://${BUCKET}/${MODEL_PATH}/export

In order to write to GCS we need to supply the TFJob with GCP credentials. We do this by telling our training code to use a Google service account.

If you followed the getting started guide for GKE then a number of steps have already been performed for you

We created a Google service account named ${DEPLOYMENT}-user
- You can run the following command to list all service accounts in your project
```
gcloud --project=${PROJECT} iam service-accounts list
```
We stored the private key for this account in a K8s secret named user-gcp-sa
- To see the secrets in your cluster
```
kubectl get secrets -n kubeflow
```

We granted this service account permission to read/write GCS buckets in this project

To see the IAM policy you can do

gcloud projects get-iam-policy ${PROJECT} --format=yaml

The output should look like the following

 bindings:
 ...
 - members:
   - serviceAccount:${DEPLOYMENT}-user@${PROJEC}.iam.gserviceaccount.com
     ...
   role: roles/storage.admin
   ...
 etag: BwV_BqSmSCY=
 version: 1

To use this service account we perform the following steps

Mount the secret into the pod

ks param set --env=${KSENV} train secret user-gcp-sa=/var/secrets

Note: ensure your envrionment is pointed at the same kubeflow namespace as the user-gcp-sa secret
Setting this ksonnet parameter causes a volumeMount and volume to be added to your TFJob
To see this you can run ks show ${KSENV} -c train

The output should now include a volumeMount and volume section

 apiVersion: kubeflow.org/v1beta1
 kind: TFJob
 metadata:
   ...
 spec:
   tfReplicaSpecs:
     Chief:
       ...
       template:
         ...
         spec:
           containers:
           - command:
             ...
             volumeMounts:
             - mountPath: /var/secrets
               name: user-gcp-sa
               readOnly: true
             ...
           volumes:
           - name: user-gcp-sa
             secret:
               secretName: user-gcp-sa
           ...

Next we need to set the environment variable GOOGLE_APPLICATION_CREDENTIALS so that our code knows where to look for the service account key.

ks param set --env=${KSENV} train envVariables GOOGLE_APPLICATION_CREDENTIALS=/var/secrets/user-gcp-sa.json

If we look at the spec for our job we can see that the environment variable GOOGLE_APPLICATION_CREDENTIALS is set.

 ks show ${KSENV} -c train

 apiVersion: kubeflow.org/v1beta1
 kind: TFJob
 metadata:
   ...
 spec:
   tfReplicaSpecs:
     Chief:
       replicas: 1
       template:
         spec:
           containers:
           - command:
             ..
             env:
             ...
             - name: GOOGLE_APPLICATION_CREDENTIALS
               value: /var/secrets/user-gcp-sa.json
             ...
           ...
     ...

You can now submit the job

ks apply ${KSENV} -c train

And you can check the job status

kubectl get tfjobs -o yaml mnist-train-dist

And to check the logs

kubectl logs -f mnist-train-dist-chief-0

Using S3

To use S3 we need we need to configure TensorFlow to use S3 credentials and variables. These credentials will be provided as kubernetes secrets and the variables will be passed in as environment variables. Modify the below values to suit your environment.

Lets start by creating an environment to store parameters particular to writing the model to S3 and running distributed.

KSENV=distributed
cd ks_app
ks env add ${KSENV}

Give the job a different name (to distinguish it from your job which didn't use S3)

ks param set --env=${KSENV} train name mnist-train-dist

Next we configure it to run distributed by setting the number of parameter servers and workers to use.

ks param set --env=${KSENV} train numPs 1
ks param set --env=${KSENV} train numWorkers 2

Now we need to configure parameters telling the code to save the model to S3.

ks param set --env=${KSENV} train modelDir ${S3_MODEL_PATH_URI}
ks param set --env=${KSENV} train exportDir ${S3_MODEL_EXPORT_URI}

In order to write to S3 we need to supply the TensorFlow code with AWS credentials we also need to set various environment variables configuring access to S3.

Define a bunch of environment variables corresponding to your S3 settings; these will be used in subsequent steps

export S3_ENDPOINT=s3.us-west-2.amazonaws.com  #replace with your s3 endpoint in a host:port format, e.g. minio:9000
export AWS_ENDPOINT_URL=https://${S3_ENDPOINT} #use http instead of https for default minio installs
export AWS_ACCESS_KEY_ID=xxxxx
export AWS_SECRET_ACCESS_KEY=xxxxx
export AWS_REGION=us-west-2
export BUCKET_NAME=mybucket
export S3_USE_HTTPS=1 #set to 0 for default minio installs
export S3_VERIFY_SSL=1 #set to 0 for defaul minio installs

Create a K8s secret containing your AWS credentials

kubectl create secret generic aws-creds --from-literal=awsAccessKeyID=${AWS_ACCESS_KEY_ID} \
  --from-literal=awsSecretAccessKey=${AWS_SECRET_ACCESS_KEY}

Pass secrets as environment variables into pod

ks param set --env=${KSENV} train secretKeyRefs AWS_ACCESS_KEY_ID=aws-creds.awsAccessKeyID,AWS_SECRET_ACCESS_KEY=aws-creds.awsSecretAccessKey

Setting this ksonnet parameter causes a two new environment variables to be added to your TFJob
To see this you can run
```
ks show ${KSENV} -c train
```

The output should now include two environment variables referencing K8s secret

apiVersion: kubeflow.org/v1beta1
kind: TFJob
metadata:
  ...
spec:
  tfReplicaSpecs:
    Chief:
      ...
      template:
        ...
        spec:
          containers:
          - command:
            ...
            env:
            - name: AWS_ACCESS_KEY_ID
              valueFrom:
                secretKeyRef:
                  key: awsAccessKeyID
                  name: aws-creds
            - name: AWS_SECRET_ACCESS_KEY
              valueFrom:
                secretKeyRef:
                  key: awsSecretAccessKey
                  name: aws-creds
            ...

Next we need to set a whole bunch of S3 related environment variables so that TensorFlow knows how to talk to S3

AWSENV="S3_ENDPOINT=${S3_ENDPOINT}"
AWSENV="${AWSENV},AWS_ENDPOINT_URL=${AWS_ENDPOINT_URL}"     
AWSENV="${AWSENV},AWS_REGION=${AWS_REGION}"
AWSENV="${AWSENV},BUCKET_NAME=${BUCKET_NAME}"
AWSENV="${AWSENV},S3_USE_HTTPS=${S3_USE_HTTPS}"
AWSENV="${AWSENV},S3_VERIFY_SSL=${S3_VERIFY_SSL}"

ks param set --env=${KSENV} train envVariables ${AWSENV}

If we look at the spec for our job we can see that the environment variables related to S3 are set.

 ks show ${KSENV} -c train

 apiVersion: kubeflow.org/v1beta1
 kind: TFJob
 metadata:
   ...
 spec:
   tfReplicaSpecs:
     Chief:
       replicas: 1
       template:
         spec:
           containers:
           - command:
             ..
             env:
             ...
             - name: AWS_REGION
               value: us-west-2
             - name: BUCKET_NAME
               value: somebucket
             ...
           ...
     ...

You can now submit the job

ks apply ${KSENV} -c train

And you can check the job

kubectl get tfjobs -o yaml mnist-train-dist

And to check the logs

kubectl logs -f mnist-train-dist-chief-0

Monitoring

There are various ways to monitor workflow/training job. In addition to using kubectl to query for the status of pods, some basic dashboards are also available.

Tensorboard

Using GCS

Configure TensorBoard to point to your model location

ks param set tensorboard --env=${KSENV} logDir ${LOGDIR}

Assuming you followed the directions above if you used GCS you can use the following value

LOGDIR=gs://${BUCKET}/${MODEL_PATH}

You need to point TensorBoard to GCP credentials to access GCS bucket with model.

Mount the secret into the pod
```
ks param set --env=${KSENV} tensorboatd secret user-gcp-sa=/var/secrets
```
- Setting this ksonnet parameter causes a volumeMount and volume to be added to TensorBoard deployment
- To see this you can run
```
ks show ${KSENV} -c tensorboard
```
- The output should now include a volumeMount and volume section
Next we need to set the environment variable GOOGLE_APPLICATION_CREDENTIALS so that our code knows where to look for the service account key.
```
ks param set --env=${KSENV} tensorboard envVariables GOOGLE_APPLICATION_CREDENTIALS=/var/secrets/user-gcp-sa.json     
```
- If we look at the spec for TensorBoard deployment we can see that the environment variable GOOGLE_APPLICATION_CREDENTIALS is set.
```
ks show ${KSENV} -c tensorboard
```
```
 ...
 env:
 ...
 - name: GOOGLE_APPLICATION_CREDENTIALS
   value: /var/secrets/user-gcp-sa.json
```

Using S3

Configure TensorBoard to point to your model location

ks param set tensorboard --env=${KSENV} logDir ${LOGDIR}

Assuming you followed the directions above if you used S3 you can use the following value

LOGDIR=s3://${BUCKET}/${MODEL_PATH}

You need to point TensorBoard to AWS credentials to access S3 bucket with model.

Pass secrets as environment variables into pod

ks param set --env=${KSENV} tensorboard secretKeyRefs AWS_ACCESS_KEY_ID=aws-creds.awsAccessKeyID,AWS_SECRET_ACCESS_KEY=aws-creds.awsSecretAccessKey

Setting this ksonnet parameter causes a two new environment variables to be added to TensorBoard deployment
To see this you can run
```
ks show ${KSENV} -c tensorboard
```

The output should now include two environment variables referencing K8s secret

 ...
 spec:
   containers:
   - command:
   ...
     env:
     ...
     - name: AWS_ACCESS_KEY_ID
       valueFrom:
         secretKeyRef:
           key: awsAccessKeyID
           name: aws-creds
     - name: AWS_SECRET_ACCESS_KEY
       valueFrom:
         secretKeyRef:
           key: awsSecretAccessKey
           name: aws-creds
           ...

Next we need to set a whole bunch of S3 related environment variables so that TensorBoard knows how to talk to S3

AWSENV="S3_ENDPOINT=${S3_ENDPOINT}"
AWSENV="${AWSENV},AWS_ENDPOINT_URL=${AWS_ENDPOINT_URL}"     
AWSENV="${AWSENV},AWS_REGION=${AWS_REGION}"
AWSENV="${AWSENV},BUCKET_NAME=${BUCKET_NAME}"
AWSENV="${AWSENV},S3_USE_HTTPS=${S3_USE_HTTPS}"
AWSENV="${AWSENV},S3_VERIFY_SSL=${S3_VERIFY_SSL}"

ks param set --env=${KSENV} tensorboard envVariables ${AWSENV}

If we look at the spec for TensorBoard deployment we can see that the environment variables related to S3 are set.

ks show ${KSENV} -c tensorboard

 ...
 spec:
   containers:
   - command:
     ..
     env:
     ...
     - name: AWS_REGION
       value: us-west-2
     - name: BUCKET_NAME
       value: somebucket
     ...

Deploying TensorBoard

Now you can deploy TensorBoard

ks apply ${KSENV} -c tensorboard

To access TensorBoard using port-forwarding

kubectl -n jlewi port-forward service/tensorboard-tb 8090:80

TensorBoard can now be accessed at http://127.0.0.1:8090.

Serving the model

The model code will export the model in saved model format which is suitable for serving with TensorFlow serving.

To serve the model follow the instructions below. The instructins vary slightly based on where you are storing your model (e.g. GCS, S3, PVC). Depending on the storage system we provide different ksonnet components as a convenience for setting relevant environment variables.

GCS

Here we show to serve the model when it is stored on GCS. This assumes that when you trained the model you set exportDir to a GCS URI; if not you can always copy it to GCS using gsutil.

Check that a model was exported

EXPORT_DIR=gs://${BUCKET}/${MODEL_PATH}/export
gsutil ls -r ${EXPORT_DIR}

The output should look something like

${EXPORT_DIR}/1547100373/saved_model.pb
${EXPORT_DIR}/1547100373/variables/:
${EXPORT_DIR}/1547100373/variables/
${EXPORT_DIR}/1547100373/variables/variables.data-00000-of-00001
${EXPORT_DIR}/1547100373/variables/variables.index

The number 1547100373 is a version number auto-generated by TensorFlow; it will vary on each run but should be monotonically increasing if you save a model to the same location as a previous location.

Set your model path

ks param set --env=${KSENV} mnist-deploy-gcp modelBasePath ${EXPORT_DIR}

Deploy it

ks apply ${KSENV} -c mnist-deploy-gcp

You can check the deployment by running

kubectl describe deployments mnist-deploy-gcp

Finally, run a service to make the deployment accessible to other pods in the cluster

ks apply ${KSENV} -c mnist-service

The service should make the mnist-deploy-gcp deployment accessible over port 9000

kubectl describe service mnist-service

S3

TODO: Add instructions

PVC

TODO: Add instructions

Web Front End

The example comes with a simple web front end that can be used with your model.

To deploy the web front end

ks apply ${KSENV} -c web-ui

Connecting via port forwarding

To connect to the web app via port-forwarding

POD_NAME=$(kubectl get pods --selector=app=web-ui --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}')

kubectl port-forward ${POD_NAME} 8080:5000

You should now be able to open up the web app at http://localhost:8080.

Using IAP on GCP

If you are using GCP and have set up IAP then you can access the web UI at

https://${DEPLOYMENT}.endpoints.${PROJECT}.cloud.goog/${NAMESPACE}/mnist/

Conclusion and Next Steps

This is an example of what your machine learning can look like. Feel free to play with the tunables and see if you can increase your model's accuracy (increasing model-train-steps can go a long way).

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README.md

README.md

Training MNIST

Prerequisites

Deploy Kubeflow

Local Setup

Modifying existing examples

Prepare model

Build and push model image.

Preparing your Kubernetes Cluster

Training your model

Local storage

Using GCS

Using S3

Monitoring

Tensorboard

Using GCS

Using S3

Deploying TensorBoard

Serving the model

GCS

S3

PVC

Web Front End

Connecting via port forwarding

Using IAP on GCP

Conclusion and Next Steps

Files

README.md

Latest commit

History

README.md

File metadata and controls

Training MNIST

Prerequisites

Deploy Kubeflow

Local Setup

Modifying existing examples

Prepare model

Build and push model image.

Preparing your Kubernetes Cluster

Training your model

Local storage

Using GCS

Using S3

Monitoring

Tensorboard

Using GCS

Using S3

Deploying TensorBoard

Serving the model

GCS

S3

PVC

Web Front End

Connecting via port forwarding

Using IAP on GCP

Conclusion and Next Steps