Configuration Reference

The JupyterHub Helm chart is configurable by values in your config.yaml. In this way, you can extend user resources, build off of different Docker images, manage security and authentication, and more.

Below is a description of the fields that are exposed with the JupyterHub Helm chart. For more guided information about some specific things you can do with modifications to the helm chart, see the Customization Guide.

proxy

proxy.secretToken

A 32-byte cryptographically secure randomly generated string used to secure communications between the hub and the configurable-http-proxy.

# to generate a value, run
openssl rand -hex 32

Changing this value will cause the proxy and hub pods to restart. It is good security practice to rotate these values over time. If this secret leaks, immediately change it to something else, or user data can be compromised

hub

hub.uid

The UID the hub process should be running as. Use this only if you are building your own image & know that a user with this uid exists inside the hub container! Advanced feature, handle with care! Defaults to 1000, which is the uid of the jovyan user that is present in the default hub image.

hub.db

hub.db.pvc

Customize the Persistent Volume Claim used when hub.db.type is sqlite-pvc.

hub.db.pvc.selector

Label selectors to set for the PVC containing the sqlite database.

Useful when you are using a specific PV, and want to bind to that and only that.

See the Kubernetes documentation for more details about using a label selector for what PV to bind to.

hub.db.pvc.storage

Size of disk to request for the database disk.

hub.db.pvc.annotations

Annotations to apply to the PVC containing the sqlite database.

See the Kubernetes documentation for more details about annotations.

hub.db.url

Connection string when hub.db.type is mysql or postgres.

See documentation for hub.db.type for more details on the format of this property.

hub.db.type

Type of database backend to use for the hub database.

The Hub requires a persistent database to function, and this lets you specify where it should be stored.

The various options are:

  1. sqlite-pvc

    Use an sqlite database kept on a persistent volume attached to the hub.

    By default, this disk is created by the cloud provider using dynamic provisioning configured by a storage class. You can customize how this disk is created / attached by setting various properties under hub.db.pvc.

    This is the default setting, and should work well for most cloud provider deployments.

  2. sqlite-memory

    Use an in-memory sqlite database. This should only be used for testing, since the database is erased whenever the hub pod restarts - causing the hub to lose all memory of users who had logged in before.

    When using this for testing, make sure you delete all other objects that the hub has created (such as user pods, user PVCs, etc) every time the hub restarts. Otherwise you might run into errors about duplicate resources.

  3. mysql

    Use an externally hosted mysql database.

    You have to specify an sqlalchemy connection string for the mysql database you want to connect to in hub.db.url if using this option.

    The general format of the connection string is:

    mysql+pymysql://<db-username>:<db-password>@<db-hostname>:<db-port>/<db-name>
    

    The user specified in the connection string must have the rights to create tables in the database specified.

    Note that if you use this, you must also set hub.cookieSecret.

  4. postgres

    Use an externally hosted postgres database.

    You have to specify an sqlalchemy connection string for the postgres database you want to connect to in hub.db.url if using this option.

    The general format of the connection string is:

    postgres+psycopg2://<db-username>:<db-password>@<db-hostname>:<db-port>/<db-name>
    

    The user specified in the connection string must have the rights to create tables in the database specified.

    Note that if you use this, you must also set hub.cookieSecret.

hub.image

Set custom image name / tag for the hub pod.

Use this to customize which hub image is used. Note that you must use a version of the hub image that was bundled with this particular version of the helm-chart - using other images might not work.

hub.image.tag

The tag of the image to pull.

This is the value after the : in your full image name.

# example tags
v1.11.1
zhy270a

hub.image.name

Name of the image, without the tag.

# example names
yuvipanda/wikimedia-hub
gcr.io/my-project/my-hub

hub.cookieSecret

A 32-byte cryptographically secure randomly generated string used to sign values of secure cookies set by the hub. If unset, jupyterhub will generate one on startup and save it in the file jupyterhub_cookie_secret in the /srv/jupyterhub directory of the hub container. A value set here will make JupyterHub overwrite any previous file.

You do not need to set this at all if you are using the default configuration for storing databases - sqlite on a persistent volume (with hub.db.type set to the default sqlite-pvc). If you are using an external database, then you must set this value explicitly - or your users will keep getting logged out each time the hub pod restarts.

Changing this value will all user logins to be invalidated. If this secret leaks, immediately change it to something else, or user data can be compromised

# to generate a value, run
openssl rand -hex 32

hub.fsGid

The gid the hub process should be using when touching any volumes mounted. Use this only if you are building your own image & know that a group with this gid exists inside the hub container! Advanced feature, handle with care! Defaults to 1000, which is the gid of the jovyan user that is present in the default hub image.

hub.labels

Extra labels to add to the hub pod.

See the Kubernetes docs to learn more about labels.

hub.extraEnv

Extra environment variables that should be set for the hub pod.

A list of EnvVar objects.

These are usually used in two circumstances:

  • Passing parameters to some custom code specified with extraConfig
  • Passing parameters to an authenticator or spawner that can be directly customized by environment variables (rarer)

hub.extraConfig

Arbitrary extra python based configuration that should be in jupyterhub_config.py.

This is the escape hatch - if you want to configure JupyterHub to do something specific that is not present here as an option, you can just write the raw Python to do it here.

Non-exhaustive examples of things you can do here:

  • Subclass authenticator / spawner to do a custom thing
  • Dynamically launch different images for different sets of images
  • Inject an auth token from GitHub authenticator into user pod
  • Anything else you can think of!

Since this is usually a multi-line string, you want to format it using YAML’s | operator.

For example:

hub:
  extraConfig: |
    c.JupyterHub.something = 'something'
    c.Spawner.somethingelse = 'something else'

No validation of this python is performed! If you make a mistake here, it will probably manifest as either the hub pod going into Error or CrashLoopBackoff states, or in some special cases, the hub running but… just doing very random things. Be careful!

hub.imagePullPolicy

Set the imagePullPolicy on the hub pod.

See the Kubernetes docs for more info on what the values mean.

singleuser

Options for customizing the environment that is provided to the users after they log in.

singleuser.memory

Set Memory limits & guarantees that are enforced for each user.

See the Kubernetes docs for more info.

singleuser.memory.limit

singleuser.memory.guarantee

Note that this field is referred to as requests by the Kubernetes API.

singleuser.imagePullSecret

Creates an image pull secret for you and makes the user pods utilize it, allowing them to pull images from private image registries.

Using this configuration option automates the following steps that normally is required to pull from private image registries.

# you won't need to run this manually...
kubectl create secret docker-registry singleuser-image-credentials \
  --docker-server=<REGISTRY> \
  --docker-username=<USERNAME> \
  --docker-email=<EMAIL> \
  --docker-password=<PASSWORD>
# you won't need to specify this manually...
spec:
  imagePullSecrets:
    - name: singleuser-image-credentials

To learn the username and password fields to access a gcr.io registry from a Kubernetes cluster not associated with the same google cloud credentials, look into this guide and read the notes about the password.

singleuser.imagePullSecret.password

Password of the user you want to use to connect to your private registry.

Examples:

  • plaintextpassword
  • abc123SECRETzyx098

For gcr.io registries the password will be a big JSON blob for a Google cloud service account, it should look something like below.

password: |-
  {
    "type": "service_account",
    "project_id": "jupyter-se",
    "private_key_id": "f2ba09118a8d3123b3321bd9a7d6d0d9dc6fdb85",
    ...
  }

Learn more in this guide.

singleuser.imagePullSecret.registry

Name of the private registry you want to create a credential set for. It will default to Docker Hub’s image registry.

Examples:

  • https://index.docker.io/v1/
  • quay.io
  • eu.gcr.io
  • alexmorreale.privatereg.net

singleuser.imagePullSecret.username

Name of the user you want to use to connect to your private registry. For external gcr.io, you will use the _json_key.

Examples:

  • alexmorreale
  • alex@pfc.com
  • _json_key

singleuser.cpu

Set CPU limits & guarantees that are enforced for each user. See: https://kubernetes.io/docs/concepts/configuration/manage-compute-resources-container/

singleuser.cpu.limit

singleuser.cpu.guarantee

singleuser.image

Set custom image name / tag used for spawned users.

This image is used to launch the pod for each user.

singleuser.image.tag

The tag of the image to use.

This is the value after the : in your full image name.

singleuser.image.pullPolicy

Set the imagePullPolicy on the singleuser pods that are spun up by the hub.

See the Kubernetes docs for more info.

singleuser.image.name

Name of the image, without the tag.

Examples:

  • yuvipanda/wikimedia-hub-user
  • gcr.io/my-project/my-user-image

singleuser.schedulerStrategy

Deprecated and no longer does anything. Use the user-scheduler instead in order to accomplish a good packing of the user pods.

auth

auth.state

auth.state.enabled

Enable persisting auth_state (if available). See: http://jupyterhub.readthedocs.io/en/latest/api/auth.html

auth.state.cryptoKey

auth_state will be encrypted and stored in the Hub’s database. This can include things like authentication tokens, etc. to be passed to Spawners as environment variables. Encrypting auth_state requires the cryptography package. It must contain one (or more, separated by ;) 32-byte encryption keys. These can be either base64 or hex-encoded. The JUPYTERHUB_CRYPT_KEY environment variable for the hub pod is set using this entry.

# to generate a value, run
openssl rand -hex 32

If encryption is unavailable, auth_state cannot be persisted.