Ray Up Not Starting Woker

  • High: It blocks me to complete my task.

Hello, I am a new ray user.

I am using Linux, and trying to connect to machines as a local cluster:
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04.4 LTS
Release: 20.04
Codename: focal

My config.yaml file looks like this:

# A unique identifier for the head node and workers of this cluster.
cluster_name: default

# Running Ray in Docker images is optional (this docker section can be commented out).
# This executes all commands on all nodes in the docker container,
# and opens all the necessary ports to support the Ray cluster.
# Empty string means disabled. Assumes Docker is installed.
    # image: "rayproject/ray-ml:latest-gpu" # You can change this to latest-cpu if you don't need GPU support and want a faster startup
    # image: rayproject/ray:latest-gpu   # use this one if you don't need ML dependencies, it's faster to pull
    image: rayproject/ray:1.12.0-py39-cpu # Sunny found this in Ray's docker repo, via the docs
    container_name: "ray_container"
    # If true, pulls latest version of image. Otherwise, `docker run` will only pull the image
    # if no cached version is present.
    pull_before_run: True
    run_options:   # Extra options to pass into "docker run"
        - --ulimit nofile=65536:65536

    type: local
    # You may need to supply a public ip for the head node if you need
    # to run `ray up` from outside of the Ray cluster's network
    # (e.g. the cluster is in an AWS VPC and you're starting ray from your laptop)
    # This is useful when debugging the local node provider with cloud VMs.
    # external_head_ip: YOUR_HEAD_PUBLIC_IP
    worker_ips: []
    # Optional when running automatic cluster management on prem. If you use a coordinator server,
    # then you can launch multiple autoscaling clusters on the same set of machines, and the coordinator
    # will assign individual nodes to clusters as needed.
    #    coordinator_address: "<host>:<port>"

# How Ray will authenticate with newly launched nodes.
    ssh_user: my.user.name
    # You can comment out `ssh_private_key` if the following machines don't need a private key for SSH access to the Ray
    # cluster:
    #   (1) The machine on which `ray up` is executed.
    #   (2) The head node of the Ray cluster.
    # The machine that runs ray up executes SSH commands to set up the Ray head node. The Ray head node subsequently
    # executes SSH commands to set up the Ray worker nodes. When you run ray up, ssh credentials sitting on the ray up
    # machine are copied to the head node -- internally, the ssh key is added to the list of file mounts to rsync to head node.
    ssh_private_key: ~/.ssh/id_rsa

# The minimum number of workers nodes to launch in addition to the head
# node. This number should be >= 0.
# Typically, min_workers == max_workers == len(worker_ips).
min_workers: 0

# The maximum number of workers nodes to launch in addition to the head node.
# This takes precedence over min_workers.
# Typically, min_workers == max_workers == len(worker_ips).
max_workers: 0
# The default behavior for manually managed clusters is
# min_workers == max_workers == len(worker_ips),
# meaning that Ray is started on all available nodes of the cluster.
# For automatically managed clusters, max_workers is required and min_workers defaults to 0.

# The autoscaler will scale up the cluster faster with higher upscaling speed.
# E.g., if the task requires adding more nodes then autoscaler will gradually
# scale up the cluster in chunks of upscaling_speed*currently_running_nodes.
# This number should be > 0.
upscaling_speed: 1.0

idle_timeout_minutes: 5

# Files or directories to copy to the head and worker nodes. The format is a
# dictionary from REMOTE_PATH: LOCAL_PATH. E.g. you could save your conda env to an environment.yaml file, mount
# that directory to all nodes and call `conda -n my_env -f /path1/on/remote/machine/environment.yaml`. In this
# example paths on all nodes must be the same (so that conda can be called always with the same argument)
file_mounts: {
#    "/path1/on/remote/machine": "/path1/on/local/machine",
#    "/path2/on/remote/machine": "/path2/on/local/machine",

# Files or directories to copy from the head node to the worker nodes. The format is a
# list of paths. The same path on the head node will be copied to the worker node.
# This behavior is a subset of the file_mounts behavior. In the vast majority of cases
# you should just use file_mounts. Only use this if you know what you're doing!
cluster_synced_files: []

# Whether changes to directories in file_mounts or cluster_synced_files in the head node
# should sync to the worker node continuously
file_mounts_sync_continuously: False

# Patterns for files to exclude when running rsync up or rsync down
    - "**/.git"
    - "**/.git/**"

# Pattern files to use for filtering out files when running rsync up or rsync down. The file is searched for
# in the source directory and recursively through all subdirectories. For example, if .gitignore is provided
# as a value, the behavior will match git's behavior for finding and using .gitignore files.
    - ".gitignore"

# List of commands that will be run before `setup_commands`. If docker is
# enabled, these commands will run outside the container and before docker
# is setup.
initialization_commands: []

# List of shell commands to run to set up each nodes.
setup_commands: []
    # If we have e.g. conda dependencies stored in "/path1/on/local/machine/environment.yaml", we can prepare the
    # work environment on each worker by:
    #   1. making sure each worker has access to this file i.e. see the `file_mounts` section
    #   2. adding a command here that creates a new conda environment on each node or if the environment already exists,
    #     it updates it:
    #      conda env create -q -n my_venv -f /path1/on/local/machine/environment.yaml || conda env update -q -n my_venv -f /path1/on/local/machine/environment.yaml
    # Ray developers:
    # you probably want to create a Docker image that
    # has your Ray repo pre-cloned. Then, you can replace the pip installs
    # below with a git checkout <your_sha> (and possibly a recompile).
    # To run the nightly version of ray (as opposed to the latest), either use a rayproject docker image
    # that has the "nightly" (e.g. "rayproject/ray-ml:nightly-gpu") or uncomment the following line:
    # - pip install -U "ray[default] @ https://s3-us-west-2.amazonaws.com/ray-wheels/latest/ray-2.0.0.dev0-cp37-cp37m-manylinux2014_x86_64.whl"

# Custom commands that will be run on the head node after common setup.
head_setup_commands: []

# Custom commands that will be run on worker nodes after common setup.
worker_setup_commands: []

# Command to start ray on the head node. You don't need to change this.
  # If we have e.g. conda dependencies, we could create on each node a conda environment (see `setup_commands` section).
  # In that case we'd have to activate that env on each node before running `ray`:
  # - conda activate my_venv && ray stop
  # - conda activate my_venv && ulimit -c unlimited && ray start --head --port=6379 --autoscaling-config=~/ray_bootstrap_config.yaml
    - ray stop
    - ulimit -c unlimited && ray start --head --port=6379 --autoscaling-config=~/ray_bootstrap_config.yaml

# Command to start ray on worker nodes. You don't need to change this.
  # If we have e.g. conda dependencies, we could create on each node a conda environment (see `setup_commands` section).
  # In that case we'd have to activate that env on each node before running `ray`:
  # - conda activate my_venv && ray stop
  # - ray start --address=$RAY_HEAD_IP:6379
    - ray stop
    - ray start --address=$RAY_HEAD_IP:6379

I can run ray up config.yaml from my head machine.
I have checked that my head machine can ssh into my worker machine and run docker.

I am testing the cluster with this script, script3.py:

from collections import Counter
import socket
import time

import ray


def f():
    # Return IP address.
    return socket.gethostbyname(socket.gethostname())

object_ids = [f.remote() for _ in range(10000)]
ip_addresses = ray.get(object_ids)

After running ray up config.yaml, if I try python script3.py, I get this error:

$ python script3.py 
[2022-04-28 23:45:50,558 C 15565 15565] raylet_client.cc:60: Could not connect to socket /tmp/ray/session_2022-04-28_15-40-47_889816_183/sockets/raylet
*** StackTrace Information ***

I subsequenty tried ray submit, with:

$ ray submit config.yaml script3.py 
Loaded cached provider configuration
If you experience issues with the cloud provider, try re-running the command with --no-config-cache.
2022-04-28 23:48:55,263 INFO node_provider.py:49 -- ClusterState: Loaded cluster state: ['', '']
Fetched IP:
Shared connection to closed.
Shared connection to closed.
Fetched IP:
Shared connection to closed.
Counter({'': 10000})
Shared connection to closed.

The output in the above, suggests that it only has a single worker. And I don’t know why it is printing the ip address as

Also, the web dashboard only shows 1 host, which is my head node.

I can run ray start --address='' on the worker machine. And it seems to connect successfully to head. However, when I do that, the browser dashboard goes blank.

The script output doesn’t change either.

What can I do to work out what is going wrong?


The problem is the quoted part: min_workers and max_workers should be removed, or set to 1.
The confusing nature of the configuration example was recently fixed in [Autoscaler][Local Node Provider] Log a warning if max_workers < len(worker_ips) by DmitriGekhtman · Pull Request #24635 · ray-project/ray · GitHub

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