docstr: Hardcode `GLOO_SOCKET_IFNAME` to `eth0` for Databricks runtime.
  
  Torch on DBR does not reliably detect the correct interface to use,
  and ends up selecting the loopback interface, breaking cross-node
  commnication.
docstr_tok: ["Hardcode","`","GLOO_SOCKET_IFNAME","`","to","`","eth0","`","for","Databricks","runtime",".","Torch","on","DBR","does","not","reliably","detect","the","correct","interface","to","use",",","and","ends","up","selecting","the","loopback","interface",",","breaking","cross-node","commnication","."]
code: def custom_environment_variables(self):
      """Hardcode `GLOO_SOCKET_IFNAME` to `eth0` for Databricks runtime.
  
      Torch on DBR does not reliably detect the correct interface to use,
      and ends up selecting the loopback interface, breaking cross-node
      commnication."""
      return {
          "GLOO_SOCKET_IFNAME": "eth0",
      }
  
file_path: ray/python/ray/util/spark/databricks_hook.py
imports: import os
  from .start_hook_base import RayOnSparkStartHook
  from .utils import get_spark_session
  import logging
  import threading
  import time
label_desc: Use image node_id 5 for calling the DefaultDatabricksRayOnSparkStartHook obj's underlying member method code with example usage: obj.custom_environment_variables() and returns: dict