The ZenML server container image is available at zenmldocker/zenml-server and can be used to deploy ZenML with a container management or orchestration tool like docker and docker-compose, or a serverless platform like Cloud Run, Container Apps and more! This guide walks you through the various configuration options that the ZenML server container expects as well as a few deployment use cases.

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Using the ZenML CLI

If you’re just looking for a quick way to deploy the ZenML server using a container, without going through the hassle of interacting with a container management tool like docker and manually configuring your container, you can use the ZenML CLI to do so. You only need to have Docker installed and running on your machine:

zenml up --docker

This command deploys a ZenML server locally in a Docker container, then connects your client to it. Similar to running plain zenml up, the server and the local ZenML client share the same SQLite database.

The rest of this guide is addressed to advanced users who are looking to manually deploy and manage a containerized ZenML server.

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ZenML Server Configuration Options

If you’re planning on deploying a custom containerized ZenML server yourself, you probably need to configure some settings for it like the database it should use, the default user details and more. The ZenML server container image uses sensible defaults, so you can simply start a container without worrying too much about the configuration. However, if you’re looking to connect the ZenML server to an external MySQL database, or to persist the internal SQLite database, or simply want to control other settings like the default account, you can do so by customizing the container’s environment variables.

The following environment variables can be passed to the container:

  • ZENML_DEFAULT_PROJECT_NAME: The name of the default project created by the server on first deployment, during database initialization. Defaults to default.

  • ZENML_DEFAULT_USER_NAME: The name of the default admin user account created by the server on first deployment, during database initialization. Defaults to default.

  • ZENML_DEFAULT_USER_PASSWORD: The password to use for the default admin user account. Defaults to an empty password value, if not set.

  • ZENML_STORE_URL: This URL should point to a SQLite database file mounted in the container, or to a MySQL compatible database service reachable from the container. It takes one of the forms:

    sqlite:////path/to/zenml.db

    or:

    mysql://username:password@host:port/database

  • ZENML_STORE_SSL_CA: This can be set to a custom server CA certificate in use by the MySQL database service. Only valid when ZENML_STORE_URL points to a MySQL database that uses SSL secured connections. The variable can be set either to the path where the certificate file is mounted inside the container or to the certificate contents themselves.

  • ZENML_STORE_SSL_CERT: This can be set to a the client SSL certificate required to connect to the MySQL database service. Only valid when ZENML_STORE_URL points to a MySQL database that uses SSL secured connections and requires client SSL certificates. The variable can be set either to the path where the certificate file is mounted inside the container or to the certificate contents themselves. This variable also requires ZENML_STORE_SSL_KEY to be set.

  • ZENML_STORE_SSL_KEY: This can be set to a the client SSL private key required to connect to the MySQL database service. Only valid when ZENML_STORE_URL points to a MySQL database that uses SSL secured connections and requires client SSL certificates. The variable can be set either to the path where the certificate file is mounted inside the container or to the certificate contents themselves. This variable also requires ZENML_STORE_SSL_CERT to be set.

  • ZENML_STORE_SSL_VERIFY_SERVER_CERT: This boolean variable controls whether the SSL certificate in use by the MySQL server is verified. Only valid when ZENML_STORE_URL points to a MySQL database that uses SSL secured connections. Defaults to False.

  • ZENML_LOGGING_VERBOSITY: Use this variable to control the verbosity of logs inside the container. It can be set to one of the following values: NOTSET, ERROR, WARN, INFO (default), DEBUG or CRITICAL.

If none of the ZENML_STORE_* variables are set, the container will default to creating and using a SQLite database file stored at /zenml/.zenconfig/local_stores/default_zen_store/zenml.db inside the container. The /zenml/.zenconfig/local_stores base path where the default SQLite database is located can optionally be overridden by setting the ZENML_LOCAL_STORES_PATH environment variable to point to a different path (e.g. a persistent volume or directory that is mounted from the host).

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Advanced Server Configuration Options

These configuration options are not required for most use cases, but can be useful in certain scenarios that require mirroring the same ZenML server configuration across multiple container instances (e.g. a Kubernetes deployment with multiple replicas):

  • ZENML_JWT_SECRET_KEY: This is a secret key used to sign JWT tokens used for authentication. If not explicitly set, a random key is generated automatically by the server and stored in the server’s global configuration. This should be set to a random string with a recommended length of at least 32 characters, e.g.: 
    from secrets import token_hex
token_hex(32)
    or: 
    openssl rand -hex 32

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Run the ZenML server with Docker

As previously mentioned, the ZenML server container image uses sensible defaults for most configuration options. This means that you can simply run the container with Docker without any additional configuration and it will work out of the box for most use cases:

docker run -it -d -p 8080:80 --name zenml zenmldocker/zenml-server

It is recommended to use a ZenML container image version that matches the version of your client, to avoid any potential API incompatibilities (e.g. zenmldocker/zenml-server:0.21.1 instead of zenmldocker/zenml-server).

The above command will start a containerized ZenML server running on your machine that uses a temporary SQLite database file stored in the container, with all the limitations that this entails (see the earlier warning). Temporary means that the database and all its contents (stacks, pipelines, pipeline runs etc.) will be lost when the container is removed with docker rm.

You can visit the ZenML dashboard at http://localhost:8080 or connect your client to the server with the default username and empty password:

$ zenml connect --url http://localhost:8080
Connecting to: 'http://localhost:8080'...
Username: default
Password for user default (press ENTER for empty password) []:
Updated the global store configuration.

The localhost URL will not work if you are using Docker based ZenML orchestrators in your stack. In this case, you need to use an IP address that is reachable from other containers instead of localhost when you connect your client to the server, e.g.:

zenml connect --url http://172.17.0.1:8080

You can manage the container with the usual Docker commands:

  • docker logs zenml to view the server logs
  • docker stop zenml to stop the server
  • docker start zenml to start the server again
  • docker rm zenml to remove the container

If you are looking for a customized ZenML server Docker deployment, you can configure one or more of the supported environment variables and then pass them to the container using the docker run --env or --env-file arguments (see the Docker documentation for more details). For example:

docker run -it -d -p 8080:80 --name zenml \
    --env ZENML_STORE_URL=mysql://username:password@host:port/database \
    zenmldocker/zenml-server

If you’re looking for a quick way to run both the ZenML server and a MySQL database with Docker, you can deploy the ZenML server with Docker Compose.

The rest of this guide covers various advanced use cases for running the ZenML server with Docker.

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Persisting the SQLite database

Depending on your use case, you may also want to mount a persistent volume or directory from the host into the container to store the ZenML SQLite database file. This can be done using the --mount flag (see the Docker documentation for more details). For example:

mkdir zenml-server
docker run -it -d -p 8080:80 --name zenml \
    --mount type=bind,source=$PWD/zenml-server,target=/zenml/.zenconfig/local_stores/default_zen_store \
    zenmldocker/zenml-server

This deployment has the advantage that the SQLite database file is persisted even when the container is removed with docker rm. However, it still suffers from the limitations incurred by using a SQLite database backend (see the earlier warning). The recommended way to deploy a containerized ZenML server is to use a MySQL database backend instead, as described in the next section.

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Docker MySQL database

As a recommended alternative to the SQLite database, you can run a MySQL database service as another Docker container and connect the ZenML server container to it.

A command like the following can be run to start the containerized MySQL database service:

docker run --name mysql -d -p 3306:3306 -e MYSQL_ROOT_PASSWORD=password mysql:5.7

If you also wish to persist the MySQL database data, you can mount a persistent volume or directory from the host into the container using the --mount flag, e.g.:

mkdir mysql-data
docker run --name mysql -d -p 3306:3306 -e MYSQL_ROOT_PASSWORD=password \
    --mount type=bind,source=$PWD/mysql-data,target=/var/lib/mysql \
    mysql:5.7

Configuring the ZenML server container to connect to the MySQL database is just a matter of setting the ZENML_STORE_URL environment variable. We use the special host.docker.internal DNS name resolved from within the Docker containers to the gateway IP address used by the Docker network (see the Docker documentation for more details). On Linux, this needs to be explicitly enabled in the docker run command with the --add-host argument:

docker run -it -d -p 8080:80 --name zenml \
    --add-host host.docker.internal:host-gateway \
    --env ZENML_STORE_URL=mysql://root:password@host.docker.internal/zenml \
    zenmldocker/zenml-server

Connecting your client to the ZenML server is the same as before:

zenml connect --url http://localhost:8080 --username default --password ''

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Direct MySQL database connection

This scenario is similar to the previous one, but instead of running a ZenML server, the client is configured to connect directly to a MySQL database running in a Docker container.

As previously covered, the containerized MySQL database service can be started with a command like the following:

docker run --name mysql -d -p 3306:3306 -e MYSQL_ROOT_PASSWORD=password mysql:5.7

The ZenML client on the host machine can then be configured to connect directly to the database with a slightly different zenml connect command:

zenml connect --url mysql://127.0.0.1/zenml --username root --password password

The localhost hostname will not work with MySQL databases. You need to use the 127.0.0.1 IP address instead.

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ZenML server with Docker Compose

Docker compose offers a simpler way of managing multi-container setups on your local machine, which is the case for instance if you are looking to deploy the ZenML server container and connect it to a MySQL database service also running in a Docker container.

To use Docker Compose, you need to install the docker-compose plugin on your machine first.

A docker-compose.yml file like the one below can be used to start and manage the ZenML server container and the MySQL database service all at once:

version: "3.9"

services:
  mysql:
    image: mysql:5.7
    ports:
      - 3306:3306
    environment:
      - MYSQL_ROOT_PASSWORD=password
  zenml:
    image: zenmldocker/zenml-server
    ports:
      - "8080:80"
    environment:
      - ZENML_STORE_URL=mysql://root:password@host.docker.internal/zenml
      - ZENML_DEFAULT_USERNAME=admin
      - ZENML_DEFAULT_PASSWORD=zenml
    links:
      - mysql
    depends_on:
      - mysql
    extra_hosts:
      - "host.docker.internal:host-gateway"
    restart: on-failure

Note the following:

  • ZENML_STORE_URL is set to the special Docker host.docker.internal hostname to instruct the server to connect to the database over the Docker network. The ZenML client knows how to handle the host.docker.internal hostname differently depending on whether it is running on the host machine or in another Docker container.
  • The extra_hosts section is needed on Linux to make the host.docker.internal hostname resolvable from the ZenML server container.
  • This example also uses the ZENML_DEFAULT_USERNAME and ZENML_DEFAULT_PASSWORD environment variables to customize the default account credentials.

To start the containers, run the following command from the directory where the docker-compose.yml file is located:

docker-compose -p zenml up -d

or, if you need to use a different filename or path:

docker-compose -f /path/to/docker-compose.yml -p zenml up -d

Connecting your client to the ZenML server is the same as before:

zenml connect --url http://localhost:8080 --username default --password ''

Tearing down the installation is as simple as running:

docker-compose -p zenml down

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Troubleshooting

You can check the logs of the container to verify if the server is up and, depending on where you have deployed it, you can also access the dashboard at a localhost port (if running locally) or through some other service that exposes your container to the internet.

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CLI Docker Deployments

If you used the zenml up --docker CLI command to deploy the Docker ZenML server, you can check the logs with the command:

zenml logs -f

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Manual Docker Deployments

If you used the docker run command to manually deploy the Docker ZenML server, you can check the logs with the command:

docker logs zenml -f

If you used the docker compose command to manually deploy the Docker ZenML server, you can check the logs with the command:

docker compose -p zenml logs -f