• Koalas is included on clusters running Databricks Runtime 7.3 and above.
• To use Koalas on a cluster running Databricks Runtime 7.0 or below, install Koalas as an Azure Databricks PyPI library.
• To use Koalas in an IDE, notebook server, or other custom applications that connect to an Azure Databricks cluster, install Databricks Connect and follow the Koalas installation instructions.

Koalas is great! This really helps ease the transition from Pandas to Spark, because you can just use the same Pandas functions/classes through the Koalas API but everything runs in the background in Spark.