At HomeAway, we use Apache Kafka as the backbone for our streaming architecture. We also like to deploy machine learning models to make realtime predictions on our data streams. Confluent KSQL provides an easy to use and interactive SQL interface for performing stream processing on Kafka. Below we show how to build a model in Python and use the model in KSQL to make predictions based on a stream of data in Kafka. We use Predictive Model Markup Language (PMML) to enable the ability to train the model using the Python library Scikit-learn, but perform model inference in Java-based KSQL.