Fix commnet

sky/backends/cloud_vm_ray_backend.py

@@ -3145,31 +3145,36 @@ def _exec_code_on_head(
  code = job_lib.JobLibCodeGen.queue_job(job_id, job_submit_cmd)
  job_submit_cmd = ' && '.join([mkdir_code, create_script_code, code])
  if len(job_submit_cmd) > 120 * 1024:
- # The maximum size of a command line argument is 128 KB. We use
- # 120KB to be safe for other arguments.
+ # The maximum size of a command line arguments is 128 KB, i.e. the
+ # command executed with /bin/sh should be less than 128KB.
  # https://github.com/torvalds/linux/blob/master/include/uapi/linux/binfmts.h
- # If the command is too long, write it to a file, rsync and execute
- # it.
+ # If a user have very long run or setup commands, the generated
+ # command may exceed the limit, as we encode the script in base64
+ # add directly include it in the job submission command. If the
+ # command is too long, we instead write it to a file, rsync and
+ # execute it.
+ # We use 120KB as a threshold to be safe for other arguments that
+ # might be added during ssh.
  ssh_credentials = backend_utils.ssh_credential_from_yaml(
  handle.cluster_yaml, handle.docker_user, handle.ssh_user)
  head_ssh_port = handle.head_ssh_port
  runner = command_runner.SSHCommandRunner(handle.head_ip,
- port=head_ssh_port,
- **ssh_credentials)
+  port=head_ssh_port,
+  **ssh_credentials)
  with tempfile.NamedTemporaryFile('w', prefix='sky_app_') as fp:
  fp.write(codegen)
  fp.flush()
- script_path = os.path.join(SKY_REMOTE_APP_DIR, f'sky_job_{job_id}')
+ script_path = os.path.join(SKY_REMOTE_APP_DIR,
+ f'sky_job_{job_id}')
  # We choose to sync code + exec, because the alternative of 'ray
  # submit' may not work as it may use system python (python2) to
  # execute the script. Happens for AWS.
  runner.rsync(source=fp.name,
- target=script_path,
- up=True,
- stream_logs=False)
+  target=script_path,
+  up=True,
+  stream_logs=False)
  job_submit_cmd = f'{mkdir_code} && {code}'
 
-
  if managed_job_dag is not None:
  # Add the managed job to job queue database.
  managed_job_codegen = managed_jobs.ManagedJobCodeGen()