For the agent-master architecture, you must install Puppet Server and, optionally, PuppetDB.
Install Puppet Server
Puppet Server is a required application that runs on the Java Virtual Machine (JVM) on the master.
In addition to hosting endpoints for the certificate authority service, Puppet Server also powers the catalog compiler, which compiles configuration catalogs for agent nodes, using Puppet code and various other data sources.
You can optionally install PuppetDB to enable extra features, including enhanced queries and reports about your infrastructure.