https://github.com/tensorflow/docs/blob/master/site/en/r1/guide/extend/architecture.md
TensorFlow has master, client, worker components. You can imagine a distributed system, and it is correct. TensorFlow is designed to make a cluster.
And here is the official document about distributed TensorFlow with sample codes.
https://github.com/tensorflow/examples/blob/master/community/en/docs/deploy/distributed.md
Here is sample cluster code by IONOS (one of the biggest German ISP.)
You can see there is parameter servers and worker servers.