Exactly what @Joseph Kambourakis​ said. Single node clusters are designed to be used for single-user machine learning use cases. Think of them as a laptop in the sky.

@E H​ ​ your use case is really good, we get this all the time. We are working hard to bring serverless clusters to the Data Science & Engineer Workspace. Once we have those, you will get super fast startup time. Is that the ideal solution in your mind for your use case?