How to assign a task to a specific node(or machine)?

Describe the problem

Suppose I have 2 machine each with one node. I make machine A the head by ray start --head --redis-port=6379 . In machine B, I make it connect with the head by ray start --redis-address=<redis-address> . Now I have the following script: @ray.remote def f(): time.sleep(0.01) return ray.services.get_node_ip_address()

With this setting, I want to assign a task node_id_address = ray.get(f.remote()) to machine A. How can I do that?

[atumanov]

We explicitly disallow exposing such topological details and using them for placement. This leads to problems. Typically, there’s an underlying reason why a user wants to place a task on a specific physical machine, e.g., data locality, task affinity, or some special resources the user knows are on that machine. In most cases you can use custom resource labels to achieve this. Here’s a good starting point for using custom resources: https://ray.readthedocs.io/en/latest/resources.html#custom-resources

[mitar]

You could define custom resource available only for machine A and then set that your task requires that resource.