Google Container Engine provisioning of a Dask Distributed cluster
Historical Note: this repository is somewhat old and not actively maintained. For more general documentation on deploying Dask on Kubernetes or Cloud clusters we recommend referring to the Dask setup documentation
This repo hosts some sample configuration to set up Kubernetes containerized environments for interactive cluster computing in Python with Jupyter notebook Dask and other tools from the PyData and SciPy ecosystems.
The Kubernetes API is provided as a managed service by the following public cloud providers:
- Google Container Engine (GKE)
- OpenShift by Red Hat
- Azure Container Service (AKS)
- Amazon Elastic Container Service for Kubernetes
Alternatively it is possible to install and manage Kubernetes by yourself.
We will briefly describe usage assuming Google Container Engine (GKE).
The dask-gke image
Dockerfile file in this repo can be used to build a docker image
with all the necessary tools to run our cluster, in particular:
pipto install additional tools and libraries,
jupyterfor the notebook interface accessed from any web browser,
bokeh(useful for the cluster monitoring web interface)
- many convenient numerical libraries
- interfaces to S3 and GCS medium-term storage solutions
This image will be used to run 3 types of services:
jupyter notebookserver, protected by password
jupyter. This password is defined in conf/jupyter_notebook_config.py; to change it, you will need to rebuild this image and point the kubernetes definitions to the new version.
dask-workerper container in the compute cluster.
Setup with Google Container Engine
You will need to install the following:
- gcloud for authentication and launching clusters
- kubectl for interacting with the kubernetes driver.
Register on the Google Cloud Platform, setup a billing account and create a project with the Google Compute Engine API enabled.
Ensure that your client SDK is up to date:
$ gcloud components update
dask-gke CLI via:
$ python setup.py install
Default settings for the cluster are stored in defaults.yaml
The easiest way to customize the cluster to your own purposes is to make a copy of this file, edit it, and supply it on the command line. The settings used for a new cluster are a combination of the built-in settings, any new values in a supplied file, and command-line options
To launch with default values only (where NAME is the label for the cluster):
dask-gke create NAME
To launch with a provided file:
dask-gke create NAME settings.yaml
To launch with a single override parameter
dask-gke create -s jupyter.port=443 NAME
By default, the process will block until done, and then print details
about the created cluster to the screen, including the addresses of
the dask-scheduler, the jupyter notebook, and the Bokeh status monitor.
This same information can be retrieved again with the
Most users will want to navigate to the notebook first, which can also
be achieved by calling
dask-gke notebook NAME
and similarly, the
status command opens the cluster status page, or
brings up the new "jupyterlab" IDE.
From within the cluster, you can connect to the distributed scheduler by doing the following:
from dask.distributed import Client c = Client('dask-scheduler:8786')
When you are done, delete the cluster with the following:
dask-gke delete NAME
Note that this asks for confirmation potentially multiple times - you might wish to
yes | (bash syntax) for automatic confirmation.
dask-gke work by calling
kubectl. For those who want finer control
or to investigate the state of the cluster,
kubectl commands can be
entered on the command line as for any other Kubernetes cluster. Furthermore,
the Kubernetes dashboard is available using
dask-gke dashboard NAME
(note that, unlike the other commands which open browser tabs, this command is blocking on the command line, since it needs to maintain a proxy connection.)
The dask workers live within containers on Google virtual machines. To get more processing power and memory, you must both increase the number of machines and the number of containers.
To add machines to the cluster, you may do the following
dask-gke resize nodes NAME COUNT
(of course, the more machines, the higher the bill will be)
To add worker containers, you may do the following
dask-gke resize pods NAME COUNT
or resize both while keeping the workers:nodes ratio constant
dask-gke resize both NAME COUNT
(you give the new number of workers requested).
Note that if you allocate more resources than your cluster can handle, some pods will not start.
To see the state of the worker pods, use
kubectl or the Kubernetes dashboard.
Kubernetes can automatically add or remove nodes to your cluster if you create the cluster with autoscaling enabled. Nodes will be added if worker pods can't be scheduled on the existing cluster, and removed if nodes are going unused.
Note that autoscaling affects the number of machines in the cluster (and consequently the cost of the cluster!), not the number of Dask workers, and must be turned on when the cluster is created.
To enable autoscaling, change the appropriate line in
defaults.yaml or run:
dask-gke create NAME -s cluster.autoscaling=True -s cluster.min_nodes=MIN -s cluster.max_nodes=MAX
we can get the logs of a specific pod with
$ kubectl logs -f dask-scheduler-hebul distributed.scheduler - INFO - Scheduler at: 10.115.249.189:8786 distributed.scheduler - INFO - http at: 10.115.249.189:9786 distributed.scheduler - INFO - Bokeh UI at: http://10.115.249.189:8787/status/ distributed.core - INFO - Connection from 10.112.2.3:50873 to Scheduler distributed.scheduler - INFO - Register 10.112.2.3:59918 distributed.scheduler - INFO - Starting worker compute stream, 10.112.2.3:59918 distributed.core - INFO - Connection from 10.112.0.6:55149 to Scheduler distributed.scheduler - INFO - Register 10.112.0.6:55103 distributed.scheduler - INFO - Starting worker compute stream, 10.112.0.6:55103 bokeh.command.subcommands.serve - INFO - Check for unused sessions every 50 milliseconds bokeh.command.subcommands.serve - INFO - Unused sessions last for 1 milliseconds bokeh.command.subcommands.serve - INFO - Starting Bokeh server on port 8787 with applications at paths ['/status', '/tasks'] distributed.core - INFO - Connection from 10.112.1.1:59452 to Scheduler distributed.core - INFO - Connection from 10.112.1.1:59453 to Scheduler distributed.core - INFO - Connection from 10.112.1.4:48952 to Scheduler distributed.scheduler - INFO - Register 10.112.1.4:54760 distributed.scheduler - INFO - Starting worker compute stream, 10.112.1.4:54760
we can also execute arbitrary commands inside the running containers with
kubectl exec, for instance to open an interactive shell session for debugging
$ kubectl exec -ti dask-scheduler-hebul bash root@dscheduler-hebul:/work# ls -l examples/ total 56 -rw-r--r-- 1 basicuser root 1344 May 17 11:29 distributed_joblib_backend.py -rw-r--r-- 1 basicuser root 33712 May 17 11:29 sklearn_parameter_search.ipynb -rw-r--r-- 1 basicuser root 14407 May 17 11:29 sklearn_parameter_search_joblib.ipynb
where "dask-scheduler-hebul" is the specific pod name of the scheduler.
It is, of course, also possible to run shell commands directly in the Jupyter
notebook, or to use python's
subprocess with dask's
programmatically call commands on the worker containers.
Alternate docker image
Each type of pod in dask-gke currently is founded on the docker image
mdurant/dask-gke:latest. The Dockerfile is included in this repo. Users
may wish to alter particularly the conda/pip installations in the middle of the work-flow.
There are two ways to apply changes made to a dask cluster:
- rebuild the docker image to the new specification, and post on dockerhub, changing
image:keys in the kubernetes .yaml files to point to it;
- set up a google image registry and build new images within your compute cluster.
To create a new password for the jupyter interface, execute the following in locally, using a jupyter of similar version to the Dockerfile (currently 4.2)
In : from notebook.auth import passwd In : passwd() Enter password: Verify password: Out: '...'
and place the created output string into
rebuildign the docker image.
The original work was completed by @ogrisel.