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Deploy MLflow models with InferenceService

This example walks you through how to deploy a mlflow model leveraging the KServe InferenceService CRD and how to send the inference request using V2 Dataplane.


The first step is to train a sample sklearn model and save as mlflow model format by calling mlflow log_model API.

# Original source code and more details can be found in:

# The data set used in this example is from
# P. Cortez, A. Cerdeira, F. Almeida, T. Matos and J. Reis.
# Modeling wine preferences by data mining from physicochemical properties.
# In Decision Support Systems, Elsevier, 47(4):547-553, 2009.

import warnings
import sys

import pandas as pd
import numpy as np
from sklearn.metrics import mean_squared_error, mean_absolute_error, r2_score
from sklearn.model_selection import train_test_split
from sklearn.linear_model import ElasticNet
from urllib.parse import urlparse
import mlflow
import mlflow.sklearn
from mlflow.models.signature import infer_signature

import logging

logger = logging.getLogger(__name__)

def eval_metrics(actual, pred):
    rmse = np.sqrt(mean_squared_error(actual, pred))
    mae = mean_absolute_error(actual, pred)
    r2 = r2_score(actual, pred)
    return rmse, mae, r2

if __name__ == "__main__":

    # Read the wine-quality csv file from the URL
    csv_url = (
        data = pd.read_csv(csv_url, sep=";")
    except Exception as e:
            "Unable to download training & test CSV, "
            "check your internet connection. Error: %s",

    # Split the data into training and test sets. (0.75, 0.25) split.
    train, test = train_test_split(data)

    # The predicted column is "quality" which is a scalar from [3, 9]
    train_x = train.drop(["quality"], axis=1)
    test_x = test.drop(["quality"], axis=1)
    train_y = train[["quality"]]
    test_y = test[["quality"]]

    alpha = float(sys.argv[1]) if len(sys.argv) > 1 else 0.5
    l1_ratio = float(sys.argv[2]) if len(sys.argv) > 2 else 0.5

    with mlflow.start_run():
        lr = ElasticNet(alpha=alpha, l1_ratio=l1_ratio, random_state=42), train_y)

        predicted_qualities = lr.predict(test_x)

        (rmse, mae, r2) = eval_metrics(test_y, predicted_qualities)

        print("Elasticnet model (alpha=%f, l1_ratio=%f):" % (alpha, l1_ratio))
        print("  RMSE: %s" % rmse)
        print("  MAE: %s" % mae)
        print("  R2: %s" % r2)

        mlflow.log_param("alpha", alpha)
        mlflow.log_param("l1_ratio", l1_ratio)
        mlflow.log_metric("rmse", rmse)
        mlflow.log_metric("r2", r2)
        mlflow.log_metric("mae", mae)

        tracking_url_type_store = urlparse(mlflow.get_tracking_uri()).scheme
        model_signature = infer_signature(train_x, train_y)

        # Model registry does not work with file store
        if tracking_url_type_store != "file":

            # Register the model
            # There are other ways to use the Model Registry,
            # which depends on the use case,
            # please refer to the doc for more information:
            mlflow.sklearn.log_model(lr, "model", signature=model_signature)

The training script will also serialise our trained model, leveraging the MLflow Model format.

├── MLmodel
├── model.pkl
├── conda.yaml
└── requirements.txt

Testing locally

Once you've got your model serialised model.pkl, we can then use MLServer to spin up a local server. For more details on MLServer, feel free to check the MLflow example doc.


this step is optional and just meant for testing, feel free to jump straight to deploying with InferenceService.


Firstly, to use MLServer locally, you will first need to install the mlserver package in your local environment, as well as the MLflow runtime.

pip install mlserver mlserver-mlflow

Model settings

The next step will be providing some model settings so that MLServer knows:

  • The inference runtime to serve your model (i.e. mlserver_mlflow.MLflowRuntime)
  • The model's name and version

These can be specified through environment variables or by creating a local model-settings.json file:

  "name": "mlflow-wine-classifier",
  "version": "v1.0.0",
  "implementation": "mlserver_mlflow.MLflowRuntime"

Start the model server locally

With the mlserver package installed locally and a local model-settings.json file, you should now be ready to start our server as:

mlserver start .

Deploy with InferenceService

When you deploy the model with InferenceService, KServe injects sensible defaults so that it runs out-of-the-box without any further configuration. However, you can still override these defaults by providing a model-settings.json file similar to your local one. You can even provide a set of model-settings.json files to load multiple models.

To use v2 protocol for inference with the deployed model you set the protocolVersion field to v2, in this eample your model artifacts have already been uploaded to a "GCS model repository" and can be accessed as gs://kfserving-examples/models/mlflow/wine.

apiVersion: ""
kind: "InferenceService"
  name: "mlflow-v2-wine-classifier"
        name: mlflow
      protocolVersion: v2
      storageUri: "gs://kfserving-examples/models/mlflow/wine"
kubectl apply -f mlflow-new.yaml

Testing deployed model

You can now test your deployed model by sending a sample request.

Note that this request needs to follow the V2 Dataplane protocol. You can see an example payload below:

  "parameters": {
    "content_type": "pd"
  "inputs": [
        "name": "fixed acidity",
        "shape": [1],
        "datatype": "FP32",
        "data": [7.4]
        "name": "volatile acidity",
        "shape": [1],
        "datatype": "FP32",
        "data": [0.7000]
        "name": "citric acid",
        "shape": [1],
        "datatype": "FP32",
        "data": [0]
        "name": "residual sugar",
        "shape": [1],
        "datatype": "FP32",
        "data": [1.9]
        "name": "chlorides",
        "shape": [1],
        "datatype": "FP32",
        "data": [0.076]
        "name": "free sulfur dioxide",
        "shape": [1],
        "datatype": "FP32",
        "data": [11]
        "name": "total sulfur dioxide",
        "shape": [1],
        "datatype": "FP32",
        "data": [34]
        "name": "density",
        "shape": [1],
        "datatype": "FP32",
        "data": [0.9978]
        "name": "pH",
        "shape": [1],
        "datatype": "FP32",
        "data": [3.51]
        "name": "sulphates",
        "shape": [1],
        "datatype": "FP32",
        "data": [0.56]
        "name": "alcohol",
        "shape": [1],
        "datatype": "FP32",
        "data": [9.4]

Now, assuming that your ingress can be accessed at ${INGRESS_HOST}:${INGRESS_PORT} or you can follow this instruction to find out your ingress IP and port.

you can use curl to send the inference request as:

SERVICE_HOSTNAME=$(kubectl get inferenceservice mlflow-v2-wine-classifier -o jsonpath='{.status.url}' | cut -d "/" -f 3)

curl -v \
  -H "Host: ${SERVICE_HOSTNAME}" \
  -H "Content-Type: application/json" \
  -d @./mlflow-input.json \

Expected Output

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