Using TraefikConsulProxy

Warning

While it works today (2023), there does not appear to be a maintained Python client for the consul API. As such, using jupyterhub-traefik-proxy with consul is deprecated in jupyterhub-traefik-proxy 1.0. You can use redis instead to achieve the same functionality (and slightly better performance).

Consul is a distributed key-value store. This and TraefikEtcdProxy is the choice to use when using jupyterhub-traefik-proxy in a distributed setup, such as a Kubernetes cluster, e.g. with multiple traefik-proxy instances.

How-To install TraefikConsulProxy

1. Install jupyterhub

2. Install jupyterhub-traefik-proxy

3. Install traefik

4. Install consul

• You can find the full installation guide and examples in the installation section

How-To enable TraefikConsulProxy

You can enable JupyterHub to work with TraefikConsulProxy in jupyterhub_config.py, using the proxy_class configuration option.

You can choose to:

• use the traefik_consul entrypoint, new in JupyterHub 1.0, e.g.:

  c.JupyterHub.proxy_class = "traefik_consul"
  

• use the TraefikConsulProxy object, in which case, you have to import the module, e.g.:

  from jupyterhub_traefik_proxy import TraefikConsulProxy
  c.JupyterHub.proxy_class = TraefikConsulProxy
  

Consul configuration

1. Depending on the value of the should_start proxy flag, you can choose whether or not TraefikConsulProxy willl be externally managed.

   • When should_start is set to True, TraefikConsulProxy will auto-generate its static configuration (using the override values or the defaults) and store it in traefik.toml file. The traefik process will then be launched using this file.

   • When should_start is set to False, prior to starting the traefik process, you must create a toml file with the desired traefik static configuration and pass it to traefik. Keep in mind that in order for the routes to be stored in consul, this toml file must specify consul as the provider.

2. TraefikConsulProxy searches in the consul key-value store the keys starting with the kv_traefik_prefix prefix in order to build its static configuration.

   Similarly, the dynamic configuration is built by searching the kv_jupyterhub_prefix.

   Note

   If you want to change or add traefik’s static configuration options, you can add them to consul under this prefix and traefik will pick them up.

   • The default values of this configurations options are:

     kv_traefik_prefix = "traefik/"
     kv_jupyterhub_prefix = "jupyterhub/"
     

   • You can override the default values of the prefixes by passing their desired values through jupyterhub_config.py e.g.:

     c.TraefikConsulProxy.kv_traefik_prefix="some_static_config_prefix/"
     c.TraefikConsulProxy.kv_jupyterhub_prefix="some_dynamic_config_prefix/"
     

3. By default, TraefikConsulProxy assumes consul accepts client requests on the official default consul port 8500 for client requests.

   c.TraefikConsulProxy.consul_url = "http://127.0.0.1:8500"
   

   If the consul cluster is deployed differently than using the consul defaults, then you must pass the consul url to the proxy using the consul_url option in jupyterhub_config.py:

   c.TraefikConsulProxy.consul_url = "scheme://hostname:port"
   

   Note

   TraefikConsulProxy does not manage the consul cluster and assumes it is up and running before the proxy itself starts. However, based on how consul is configured and started, TraefikConsulProxy needs to be told about some consul configuration details, such as:

   • consul address where it accepts client requests

     c.TraefikConsulProxy.consul_url = "scheme://hostname:port"
     

   • consul credentials (if consul has acl enabled)

       c.TraefikConsulProxy.consul_password = "123"
     

   Checkout the consul documentation to find out more about possible consul configuration options.

Externally managed TraefikConsulProxy

If TraefikConsulProxy is used as an externally managed service, then make sure you follow the steps enumerated below:

1. Let JupyterHub know that the proxy being used is TraefikConsulProxy, using the proxy_class configuration option:

   c.JupyterHub.proxy_class = "traefik_consul"
   

2. Configure TraefikConsulProxy in jupyterhub_config.py

   JupyterHub configuration file, jupyterhub_config.py must specify at least:

   • That the proxy is externally managed

   • The traefik api credentials

   • The consul credentials (if consul acl is enabled)

   Example configuration:

   # JupyterHub shouldn't start the proxy, it's already running
   c.TraefikConsulProxy.should_start = False
   
   # if not the default:
   c.TraefikConsulProxy.consul_url = "http://consul-host:2379"
   
   # traefik api credentials
   c.TraefikConsulProxy.traefik_api_username = "abc"
   c.TraefikConsulProxy.traefik_api_password = "123"
   
   # consul acl token
   c.TraefikConsulProxy.consul_password = "456"
   

3. Create a toml file with traefik’s desired static configuration

   Before starting the traefik process, you must create a toml file with the desired traefik static configuration and pass it to traefik when you launch the process. Keep in mind that in order for the routes to be stored in consul, this toml file must specify consul as the provider/

   • Keep in mind that the static configuration must configure at least:

     • The default entrypoint

     • The api entrypoint

     • The consul provider

   Example:

   # enable the api
   [api]
   
   # the public port where traefik accepts http requests
   [entryPoints.http]
   address = ":8000"
   
   # the port on localhost where the traefik api should be found
   [entryPoints.auth_api]
   address = "localhost:8099"
   
   [providers.consul]
   # the consul username (if auth is enabled)
   username = "def"
   # the consul password (if auth is enabled)
   password = "456"
   # the consul address
   endpoints = ["127.0.0.1:8500"]
   # the prefix to use for the static configuration
   rootKey = "traefik"
   

   Note

   If you choose to enable consul Access Control Lists (ACLs) to secure the UI, API, CLI, service communications, and agent communications, you can use this toml file to pass the credentials to traefik, e.g.:

   [providers.consul]
   password = "admin"
   ...
   

Example setup

This is an example setup for using JupyterHub and TraefikConsulProxy managed by another service than JupyterHub.

1. Configure the proxy through the JupyterHub configuration file, jupyterhub_config.py, e.g.:

   # mark the proxy as externally managed
   c.TraefikConsulProxy.should_start = False
   
   # traefik api endpoint login password
   c.TraefikConsulProxy.traefik_api_password = "abc"
   
   # traefik api endpoint login username
   c.TraefikConsulProxy.traefik_api_username = "123"
   
   # consul url where it accepts client requests
   c.TraefikConsulProxy.consul_url = "http://127.0.0.1:8500"
   
   # configure JupyterHub to use TraefikConsulProxy
   c.JupyterHub.proxy_class = "traefik_consul"
   

   Note

   If you intend to enable consul acl, add the acl token to jupyterhub_config.py under consul_password:

   # consul token
   c.TraefikConsulProxy.consul_password = "456"
   

2. Starts the agent in development mode on the default port on localhost. e.g.:

   $ consul agent -dev
   

   Note

   If you intend to enable consul acl, checkout this guide.

3. Create a traefik static configuration file, traefik.toml, e.g:.

   # enable the api
   [api]
   
   # the public port where traefik accepts http requests
   [entryPoints.http]
   address = ":8000"
   
   # the port on localhost where the traefik api should be found
   [entryPoints.auth_api]
   address = "localhost:8099"
   
   [providers.consul]
   # the username (if auth is enabled)
   username = "def"
   # the password (if auth is enabled)
   password = "456"
   # the consul address
   endpoints = ["127.0.0.1:8500"]
   # the prefix to use for the static configuration
   rootKey = "traefik"
   

4. Start traefik with the configuration specified above, e.g.:

   $ traefik -c traefik.toml