Are Radisson Nodes Running on Redis Server Nodes?

I am testing RScheduledExecutorService of Redisson. From this Artice: https://dzone.com/articles/distributed-tasks-execution-and-scheduling-in-java

I understand the scheduling tasks (Java Callable or Java Runnable ) will be serialized and will be sent to remote Redisson Nodes for remote scheduling & executing.

The definitions of Redisson Nodes:

Redisson Node is a standalone Java application whose sole purpose is to execute tasks that have been submitted to the same Redis instance it's connected to.

I have some questions:

1. What machines that Redisson Nodes running on? Are they Redis Server Nodes (machines)?

2. If Radission Nodes running on Redis Server Nodes -> It means I need to install JRE on every Redis Server Nodes?

3. If Redission Nodes running on separate server nodes -> It means I need to have extra server nodes (machines) for Redisson Nodes purposes.

4. Let's say I have 3 Redisson Nodes. From a Java application server instance, I submit a task. Will this task will be run 3 times? (Each Redisson Node will run the task once)

Thank you!