[Constellation](https://github.com/jpmorganchase/constellation) / [Tessera](https://github.com/jpmorganchase/tessera) is used to provide the private Transaction Manager for a Quorum node. Once a Constellation/Tessera node is running, the `PRIVATE_CONFIG` environment variable is used to point the Quorum node to the transaction manager instance. Examples of this can be seen in the [quorum-examples 7nodes](https://github.com/jpmorganchase/quorum-examples) source files.