code: def start_jobs():
      n_nodes = len([s for s in SERVERS])
      run_uuid = experiment.generate_uuid()
      master_addr = None
      world_size = n_nodes * PROC_PER_NODE
  
      for node_rank, server in enumerate(SERVERS):
          if master_addr is None:
              master_addr = SERVERS[server].conf.hostname
  
          for local_rank in range(PROC_PER_NODE):
              rank = node_rank * PROC_PER_NODE + local_rank
              env_vars = {
                  "GLOO_SOCKET_IFNAME": "enp1s0",
                  "RUN_UUID": run_uuid,
                  "MASTER_ADDR": master_addr,
                  "MASTER_PORT": f"{1234}",
                  "WORLD_SIZE": f"{world_size}",
                  "RANK": f"{rank}",
                  "LOCAL_RANK": f"{local_rank}",
              }
  
              if PROC_PER_NODE > 1:
                  env_vars["OMP_NUM_THREADS"] = "1"
  
              cmd = ["python", "mnist.py"]
  
              tags = TAGS.copy()
              if node_rank == 0 and local_rank == 0:
                  tags += ["master"]
  
              JOBS.create(server, " ".join(cmd), env_vars, tags).start()
              time.sleep(1)
  
imports: import time
  from labml import experiment
  from labml_remote.job import JOBS
  from labml_remote.server import SERVERS
label_desc: Use image node_id 1 for calling a global function with example usage: start_jobs() without return types